{"title":"VSRs","description":"","products":[{"product_id":"pro-con-vsr-voltage-sensitive-relay-12-24-auto-select-plus-fine-adjust-1","title":"Voltage Sensitive Relay Pro Connect VSR","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca target=\"_blank\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_and_VSR_E_G_F.pdf?488\" rel=\"noopener noreferrer\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_medium.jpg?760\"\u003e  Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003c\/h4\u003e\n\u003ch4\u003e\u003ca target=\"_blank\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_VSR_IFs_76643d9c-e2ec-4525-b79b-f1749c96b582.pdf?762\" rel=\"noopener noreferrer\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_09f43697-3d7a-44fa-8988-8aff196e7ffa_medium.jpg?761\"\u003e Product Information\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePro Connect VSR 80, 160 \u0026amp; 240 amp\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDC Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eSize L x W x D mm \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eWeight Kg\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e12 \u0026amp; 24 auto\u003c\/td\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e140 x 180 x 40\u003c\/td\u003e\n\u003ctd\u003e0.1\u003c\/td\u003e\n\u003ctd\u003eVSR80\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e12 \u0026amp; 24 auto\u003c\/td\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e140 x 190 x 40\u003c\/td\u003e\n\u003ctd\u003e0.2\u003c\/td\u003e\n\u003ctd\u003eVSR160\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e12 \u0026amp; 24 auto\u003c\/td\u003e\n\u003ctd\u003e240\u003c\/td\u003e\n\u003ctd\u003e140 x 200 x 40\u003c\/td\u003e\n\u003ctd\u003e0.25\u003c\/td\u003e\n\u003ctd\u003eVSR240\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive activated relays:\u003c\/strong\u003e\u003cbr\u003eThis product would be regarded as the next level up from the signal feed relay, the main difference being that it is totally automatic - this relay does not require an ignition feed to operate, it works on monitoring the input voltage to the device (usually the starter battery or battery bank with other charging source such as a battery charger or wind gen), when this voltage exceeds 13.3V the processor makes the assumption that the alternator \/ battery charger or other power device is active and as such it will automatically engage the relay to connect the main battery bank to the auxiliary battery bank and so charge the auxiliary battery. Conversely, when the voltage drops below 12.9V the processor in the relay assumes that either the engine has been stopped or the load on the aux battery is pulling the starter battery down too much and for safety reasons it should be isolated. In a nut shell this is easier to install than the above and is smarter, however, it has some of the same limitations as the standard signal relay. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIdeal applications:\u003c\/strong\u003e See signal relay applications. Also ideal for charging a secondary battery bank from a battery charger which has only one output such as combined inverter charger. The starter motor interlock connection prevents the starter motor current being pulled through the relay and damaging the relay.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIts limitations:\u003c\/strong\u003e See the limitations for the signal relay. Another major problem with standard relays is their ability to switch off under high load. The main job of a voltage sensitive relay is to sense any major current being taken out of the starter battery (primary) and to stop it. For example, if we take a typical 12V boat system with an 80A alternator and install a standard 80A VSR on the engine starter battery bank to charge the secondary battery (domestic battery bank, anchor winch or bow thruster battery bank). On engine start up the alternator will raise the voltage on the starter battery and this will engage the relay to charge the secondary battery bank (so far so good). However, for the sake of argument say the secondary battery bank is discharged (i.e. first thing in the morning) and then someone switches on a 2000W inverter, or a bow thruster or the anchor winch, these items will attempt to draw 200A + from the secondary battery bank. However, because the secondary battery is nearly empty, the load (200 amps) will automatically attempt to draw this current from the highest voltage source which, in this case, would be the starter battery bank. Obviously we do not want this to happen as we do not want to drain the starter battery or burn out the 80A relay or even worse set fire to the cables because you are now trying to pull 200A plus down these cables. In theory the large current flow through the VSR will drop the starter battery voltage and so trigger the relay to open circuit and so switch off this circuit stopping the drain and saving the day. However, a relay has 3 main ratings, for example, an 80A relay can take 80A all day no problem, (hence its continuous rating) and has a short term overload of about 400A for about 1\/10th sec. It has a third rating, however, that is much more important; that is the maximum current it can open circuit at. The assumption by the public is that an 80A relay can open circuit at 80A, but that is not so, it has an open circuit current rating of about 30-40A. And so the problem becomes apparent, the high load on the secondary battery system (in the above example) causes an instant load of 200A + on the relay (that's ok, it can deal with this for a split second) then the control circuit attempts to open the relay to stop this discharge, then BANG you open the relay with 200A going through it (with an open circuit rating of about 40 amps) and so you cause a large back E.M.F. If you're lucky, it will vaporise the contacts blowing them in to small pieces and open circuit the relay destroying the product. To reduce this effect, Sterling puts anti back E.M.F. spark reducers on all relay products.\u003cbr\u003eAdjustable: This unit comes factory set to bi-directional activation and can be fitted with no adjustments required to operate as a Voltage sensitive relay straight out of the box, it is auto voltage adjustment so it can be fitted to a 12 or 24V circuit, however, the following things can also be adjusted if desired.\u003cbr\u003e            Unit directional activation:\u003cbr\u003e\u003cstrong\u003eFunction 1:\u003c\/strong\u003e  Charging activated by starter battery voltage increase (engine on). This is the most common setting and the factory default setting. This setting also does not have an ignition feed requirement. This connects the primary and secondary banks based on a voltage in excess of 13.3V being sensed on the primary battery only (the engine starter battery). The 2nd battery bank, once connected would only disconnect when both battery banks drop below 13.0V on both sides. The 13V safety threshold is still activated to protect and seperate the batteries if, or when, the drain that invoked this function (voltage drops below 13V) once the unit has tripped, will not re-engage until the voltage on the primary battery bank (the engine start) has exceeded 13.3V again. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 2: \u003c\/strong\u003e Charging either way (bi directional), based on a voltage rise on either side of the unit (default setting). This function will close the relay at 13.3V sensed on either side of the relay, a good example of this would be the use of a combi inverter charger on the domestic battery bank, because most combi’s only have a single output charging line (to the domestic battery bank) then with this function the unit will charge from the combi to the starter battery bank (in effect giving you 2 outputs from the battery charger) when the combi is on, but also charge from the alternator to the domestic battery bank when the combi is off. In either mode the unit still has the 13.3V on and 13V off mode and the current limit function. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 3: \u003c\/strong\u003e Charging batteries one way only. This function allows a charge to flow from the alternator, or battery to battery charger, or any other charging source to a secondary battery bank, but only when the engine is running. In effect, this mode only allows current flow from the primary source to the secondary, and will continue to flow until either there is an overload threat or a low voltage threat to the primary battery or the engine is shut down. This function requires an extra wire to the unit, an ignition feed, that informs the unit if the engine is running or not.\u003cbr\u003e\u003cstrong\u003eVoltage parameter activation:\u003c\/strong\u003e Voltage activation and deactivation parameters can be adjusted using the setup command.\u003cbr\u003eAuto 12\/24V selection, the unit will auto select the system voltage using the following, if it senses 4 to16V it will lock to 12V , if it sees 16-30V it will lock to 24V. If for some reason the input voltage is very low (in the case of an empty 24V system), then the product can be disconnected and allowed to re-engage,  once locked the product will hold that setting until fully isolated again.\u003cbr\u003eBoth the VSR and the CVSR unit are fitted with the latest active progressive disconnect algorithm to ensure that the batteries can charge even where large differential voltages exist. As such there will be various time delays between what the customer has preset as the turn ‘off’ voltage point and the product actually turning off. The time delay will reduce the lower the voltage is below the programmed disconnect voltage.\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e0.01 volt drop\u003c\/td\u003e\n\u003ctd\u003eIgnition feed (not always required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWaterproof to IP65\u003c\/td\u003e\n\u003ctd\u003eSAEJ1171 ignition protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHigh overload surge rating\u003c\/td\u003e\n\u003ctd\u003eBack EMF spark arrester\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRemote LED connection\u003c\/td\u003e\n\u003ctd\u003eNo ignition feed voltage drop\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuppression diodes across relay to prolong life\u003c\/td\u003e\n\u003ctd\u003eTime delay to prevent engine starter damage\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle \u0026amp; Twin starter motor disengage connections\u003c\/td\u003e\n\u003ctd\u003e12V \u0026amp; 24V automatic selection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eExtremely low quiescent current approx 1 mA\u003c\/td\u003e\n\u003ctd\u003eCustom voltage adjustment parameters available\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eActive progressive disconnect algorithm\u003c\/td\u003e\n\u003ctd\u003eAutomatic voltage activation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAutomatic voltage de activation\u003c\/td\u003e\n\u003ctd\u003eProtects primary battery from discharge\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEmergency auxillary forced activation\u003c\/td\u003e\n\u003ctd\u003eHigh battery voltage trip protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e5 LED information display\u003c\/td\u003e\n\u003ctd\u003e5 alarm functions and safety trips plus information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdjustable relay trigger side operation\u003c\/td\u003e\n\u003ctd\u003eShort circuit protection (prior to engagement)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eWhich model suits my needs best ?\u003c\/strong\u003e\u003cbr\u003e1) The first part is easy, what is the max size of your alternator or charging device. I.e. do you have a 90A alternator or a 100A battery charger charging the primary battery bank. This means that the secondary battery could be subjected to at least that load, so, the relay must be able to comfortably handle that sort of current continuously. It would be wise to give the relay a good 10-20% comfort zone, i.e. always up-size the relay if the charging source and relay are the same, for example, if you have an 80A alternator, combi or battery charger with an 80A relay then go to the 160A relay option to be safe.\u003cbr\u003e\u003cbr\u003e2) Next its cost of installation and ease of installation. If you are fitting the unit and access to ignition feeds is simple then the Ignition Feed system should be entertained, however, if not then the Voltage Sensitive Relay version is much simpler to fit and totally automatic, and has a lot more functions.\u003cbr\u003e\u003cbr\u003e3) Do you need to vary which side of the relay activates the unit, or even ensure the unit is isolated (via ignition feed, or even adjust the standard voltage parameters, all this is possible on the Voltage Sensitive Relay).\u003cbr\u003e\u003cbr\u003e4) The last, but most important aspect is safety. The most important thing here is to establish what the maximum possible load is  that could be placed on the secondary battery bank when the relay is engaged, i.e. a large inverter \/ anchor winch, bow thruster. Remember that every load you put on, the secondary battery will have a percentage of this load transferred to the primary battery depending on how full the secondary battery is. This could range from a few percent to 100 percent, so, it is important that the relay system can deal with this high load without damage. If there are large potential loads such as hundreds of amps then the only way to do this is using a Current Limiting Voltage Sensitive Relay because when exposed to excessive currents, the current limiting models simply and safely shut down until the excessive current is removed, i.e. switched off, then it can automatically re-instate itself and carry on after that large surge load has stopped. This removes the need for excessive cabling and ensures a safe installation with less reliance on fuses for protection.\u003c\/p\u003e","brand":"Sterling Power Product","offers":[{"title":"VSR 80A 12\/24 Auto select","offer_id":884583603,"sku":"VSR80","price":76.03,"currency_code":"GBP","in_stock":true},{"title":"VSR 160A 12V\/24V Autoselect","offer_id":899564059,"sku":"VSR160","price":86.17,"currency_code":"GBP","in_stock":true},{"title":"VSR 240A 12V\/24V Autoselect","offer_id":899564515,"sku":"VSR240","price":103.91,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/products\/IMG_6609white.jpg?v=1413296216"},{"product_id":"voltage-sensitive-relay-analogue-80-160a-12-24v","title":"Voltage Sensitive Relay Analogue 80-160A 12\/24V","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca target=\"_blank\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_ins_eng_ger_fren_348fbc80-b7a0-4f91-afd3-add8fae2a781.pdf?491\" rel=\"noopener noreferrer\"\u003e\u003cimg src=\"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_a5a459c2-fe25-4183-9703-f70f261a5d4c_medium.jpg?2851008086890650313\"\u003e Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003c\/h4\u003e\n\u003ch4\u003e\n\u003ca target=\"_blank\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" rel=\"noopener noreferrer\"\u003e\u003cimg src=\"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRs_medium.jpg?924\"\u003e\u003c\/a\u003e\u003ca target=\"_blank\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" rel=\"noopener noreferrer\"\u003e Product Information PDF\u003c\/a\u003e\n\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive Relay Analogue Fixed Programme\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eContinuous Current \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eOverload Ability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e12\u003c\/td\u003e\n\u003ctd\u003e80 amps\u003c\/td\u003e\n\u003ctd\u003e200 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA8012\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e12\u003c\/td\u003e\n\u003ctd\u003e160 amps\u003c\/td\u003e\n\u003ctd\u003e400 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA16012\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e24\u003c\/td\u003e\n\u003ctd\u003e80 amps\u003c\/td\u003e\n\u003ctd\u003e200 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA8024\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e24\u003c\/td\u003e\n\u003ctd\u003e160 amps\u003c\/td\u003e\n\u003ctd\u003e400 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA16024\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage sensitive relay analogue vs digital\u003c\/strong\u003e\u003cbr\u003eThere are 2 main types of voltage sensitive relays on the market, by far the most common is the lower cost analogue  model (The Sterling analogue model has the added advantage of 8 mm stud connectors and IP68 rating), (fully waterproof), this type of device is very basic and simply switches on and off between two preset voltages with a 40 or so second time delay. This product works fine for the majority of installations where the second battery banks is only being charged when the engine is running and there is no real current drawn from the second battery set while the vehicle is on the move, ideal for most vehicle operation, however, things get more complex where there is current being drawn while the engine (on a boat or while a vehicle is not moving but the engine is running) or the batteries are the more exotic batteries such as AGM are being used (where different voltage switching is required) then the limitations of the analogue (no adjustable aspect) unit can be over come with the more expensive but much more controllable digital unit. The digital unit offers the operator a wide switching voltage range to chose from ensuring the open circuit voltage is above the discharge voltages of AGM, Gel and lithium, also the unit’s bi-directional features may be required, and last but by no means least a switching algorithms is used to prevent unnecessary switching of the relay.  Also, because a digital unit is active all the time the quiescent current of the product is vital, i.e. the current it takes to run the product, in the case of the Sterling is less than 1 mA that’s 0.001A which is about 1A per week usage. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhy would I want to adjust a voltage sensitive relay?\u003c\/strong\u003e\u003cbr\u003e1) Most Analogue VSRs come preset (for 24V x 2) to engage at 13.3V and disengage about 12.8V. Where as this is ok for normal lead acid batteries an AGM, Gel and Lithium battery have a much higher surface which will require adjustment voltages as high as 13V, this makes standard relay settings incorrect and will require the thresholds to be adjusted up. Batteries would be partially discharged at this voltage and would require switching off at about 13.2V. This could not be achieved with a fixed analogue model but there is no problem with the digital.\u003cbr\u003e2) Directional control, Most analogue VSRs are preset as Bi-directional activation, i.e. if either the second battery or the first battery reaches the required trigger voltage the unit will work, however, there are times when the system wants to have the unit activated from the first battery but not activated from the secondary battery, this is called unidirectional, the digital version can do this.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eDigital\u003c\/strong\u003e\u003cbr\u003eThe digital unit has a unique built in magnetic program ability, the lid of the unit has an in built magnet and the unit has an internal reed switch to pick up the magnets pulse generated by the user when the unit requires reprogramming this allows the product to be totally programmable by the lid but still maintained the waterproof integrity.  \u003cbr\u003e \u003cbr\u003eThis unit is fitted with the latest on\/off algorithms to prevent unnecessary switching, and has an extremely low quiescent current of less than 1 mA \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhat size of relay do I require?\u003c\/strong\u003e\u003cbr\u003eTo match a relay to your system the important things are \u003cbr\u003e1) Ensure the amp ratings of the relay 10 - 20 % is larger than the largest charging source.\u003cbr\u003e2) Ensure no load on the secondary battery bank exceeds the rating of the relay when on.\u003cbr\u003eIn the event of having a large load such as a 2000W + inverter, anchor winch or bow thruster then please look at our range of Current Limiting Voltage sensitive relays to deal with these high loads. \u003cbr\u003eIf the relay is to be used on a battery bank with a solar cell which is required to charge other batteries when the engine\/battery charger is off then please look at the Latching Relay products, as this is more suitable for that operation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFeatures of the Analogue VSR\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eIP66 Waterproof\u003c\/td\u003e\n\u003ctd\u003eFixed voltage switching\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFixed time switching delay\u003c\/td\u003e\n\u003ctd\u003e12 or 24V unit only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnti relay contact arching protection\u003c\/td\u003e\n\u003ctd\u003eHigh quality brass connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelay electrical override ability\u003c\/td\u003e\n\u003ctd\u003e1 LED active information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBi directional operation only\u003c\/td\u003e\n\u003ctd\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Sterling Power Product","offers":[{"title":"12V 80A  VSRA8012","offer_id":884635767,"sku":"VSRA8012","price":86.4,"currency_code":"GBP","in_stock":false},{"title":"12V 160A VSRA16012","offer_id":884635775,"sku":"VSRA16012","price":96.0,"currency_code":"GBP","in_stock":true},{"title":"24V 160A VSRA16024","offer_id":884635783,"sku":"VSRA16024","price":96.0,"currency_code":"GBP","in_stock":true},{"title":"24V 80A VSRA8024","offer_id":884635779,"sku":"VSRA8024","price":86.4,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/products\/IMG_6729white.jpg?v=1412939924"},{"product_id":"voltage-sensitive-relay-digital-80-160a-12-24v","title":"Voltage Sensitive Relay Digital 80 - 160A 12\u002624V","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4 style=\"text-align: left;\"\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/instructions_b1840fb8-6914-4c02-ace8-f4478c02ba81.pdf?18\" target=\"_blank\"\u003e\u003cimg alt=\"\" src=\"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/vsrb_medium.jpg?2851008086890650313\" style=\"float: none;\"\u003e Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003c\/h4\u003e\n\u003ch4\u003e\n\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRs_medium.jpg?924\"\u003e\u003c\/a\u003e\u003ca href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e Product Information PDF\u003c\/a\u003e\n\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003cstrong\u003eVoltage Sensitive Relay - Digital\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eVolts\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eContinuous Current\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eOverload Ability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e12\/24\u003c\/td\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e200A\u003c\/td\u003e\n\u003ctd\u003eVSRB80\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e12\/24\u003c\/td\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e400A\u003c\/td\u003e\n\u003ctd\u003eVSRB160\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage sensitive relay analogue vs digital\u003c\/strong\u003e\u003cbr\u003eThere are 2 main types of voltage sensitive relays on the market, by far the most common is the lower cost analogue  model (The Sterling analogue model has the added advantage of 8 mm stud connectors and IP66 rating), (fully waterproof), this type of device is very basic and simply switches on and off between two preset voltages with a 40 or so second time delay. This product works fine for the majority of installations where the second battery banks is only being charged when the engine is running and there is no real current drawn from the second battery set while the vehicle is on the move, ideal for most vehicle operation, however, things get more complex where there is current being drawn while the engine (on a boat or while a vehicle is not moving but the engine is running) or the batteries are the more exotic batteries such as AGM are being used (where different voltage switching is required) then the limitations of the analogue (no adjustable aspect) unit can be over come with the more expensive but much more controllable digital unit. The digital unit offers the operator a wide switching voltage range to chose from ensuring the open circuit voltage is above the discharge voltages of AGM, Gel and lithium, also the unit’s bi-directional features may be required, and last but by no means least a switching algorithms is used to prevent unnecessary switching of the relay. Also, because a digital unit is active all the time the quiescent current of the product is vital, i.e. the current it takes to run the product, in the case of the Sterling is less than 1 mA that’s 0.001A which is about 1A per week usage. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhy would I want to adjust a voltage sensitive relay?\u003c\/strong\u003e\u003cbr\u003e1) Most Analogue VSRs come preset (for 24V x 2) to engage at 13.3V and disengage about 12.8V. Where as this is ok for normal lead acid batteries an AGM, Gel and Lithium battery have a much higher surface which will require adjustment voltages as high as 13V, this makes standard relay settings incorrect and will require the thresholds to be adjusted up. Batteries would be partially discharged at this voltage and would require switching off at about 13.2V. This could not be achieved with a fixed analogue model but there is no problem with the digital.\u003cbr\u003e2) Directional control, Most analogue VSRs are preset as Bi-directional activation, i.e. if either the second battery or the first battery reaches the required trigger voltage the unit will work, however, there are times when the system wants to have the unit activated from the first battery but not activated from the secondary battery, this is called unidirectional, the digital version can do this.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eDigital\u003c\/strong\u003e\u003cbr\u003eThe digital unit has a unique built in magnetic program ability, the lid of the unit has an in built magnet and the unit has an internal reed switch to pick up the magnets pulse generated by the user when the unit requires reprogramming this allows the product to be totally programmable by the lid but still maintained the waterproof integrity.  \u003cbr\u003e \u003cbr\u003e\u003cbr\u003eThis unit is fitted with the latest on\/off algorithms to prevent unnecessary switching, and has an extremely low quiescent current of less than 1 mA \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhat size of relay do I require?\u003c\/strong\u003e\u003cbr\u003eTo match a relay to your system the important things are \u003cbr\u003e1) Ensure the amp ratings of the relay 10 - 20 % is larger than the largest charging source.\u003cbr\u003e2) Ensure no load on the secondary battery bank exceeds the rating of the relay when on.\u003cbr\u003eIn the event of having a large load such as a 2000W + inverter, anchor winch or bow thruster then please look at our range of Current Limiting Voltage sensitive relays to deal with these high loads. \u003cbr\u003eIf the relay is to be used on a battery bank with a solar cell which is required to charge other batteries when the engine\/battery charger is off then please look at the Latching Relay products as this is more suitable for that operation. \u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFeatures of the Digital VSR\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eIP66 Waterproof\u003c\/td\u003e\n\u003ctd\u003eDigital algorithm switching delay\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAuto select 12V and 24V unit\u003c\/td\u003e\n\u003ctd\u003eAdjustable switching voltage settings\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHigh voltage disconnect\u003c\/td\u003e\n\u003ctd\u003eLow voltage warning\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnti relay contact arching protection\u003c\/td\u003e\n\u003ctd\u003eHigh quality brass connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelay electrical override ability\u003c\/td\u003e\n\u003ctd\u003e3 LED information rail\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdjustable Uni or Bi directional\u003c\/td\u003e\n\u003ctd\u003eReverse polarity protection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Sterling Power Product","offers":[{"title":"12\/24V 80A VSRB80","offer_id":884647415,"sku":"VSRB80","price":148.8,"currency_code":"GBP","in_stock":true},{"title":"12\/24V 160A VSRB160","offer_id":884647419,"sku":"VSRB160","price":153.6,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/products\/IMG_6732white.jpg?v=1412940799"},{"product_id":"12v-battery-high-voltage-protection-device-60a-rated","title":"12V battery High Voltage Protection Device 60A rated","description":"\u003cp\u003eThe HVDC12 is a 12V battery protection device that protects your 12V battery(s) and your 12V system from instant and \/ or sustained high DC voltage spikes that can occur in your DC system. These voltage spikes can occur due to malfunctioning solar charge controllers \/ regulator and \/ or wind regulators. The HVDC can work with both lead acid and lithium batteries.\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eSolar regulators and wind regulators can, and do, fail and have serious consequences to your DC system. Often putting the unregulated solar or wind voltage directly across the 12V battery terminal. This can lead to 16V-\u0026gt;35V+ being directly dumped on to your 12V battery and your 12V system. The impact on inverters, DC DC chargers (BBs), 12V anciliary equipment (fridges, pumps etc..) will be deleterious. This HVDC12 is designed to protect against these episdoes. \u003c\/p\u003e\n\u003cp\u003eThe HVDC12 has 2 studs. 1 of the terminals should be connected to your 12V battery \/ 12V system i.e. the 12V system you wish to protect. The other terminal is connected to your potentially risky solar regulator \/ wind generator \/ other potentially high voltage device.\u003c\/p\u003e\n\u003cp\u003eThe HVDC12 is good for 60A at 100VDC - the relay shall trip to protect at 16V+ and the red LED illuminates. The relay then requires manual re-engagement. \u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eRule of thumb:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e- Inverters, normal 12V battery chargers, 12V battery to battery chargers, 12V anciliaries (pumps \/ fridges) etc.. should be on the '\u003cem\u003e\u003cstrong\u003e12V battery side\u003c\/strong\u003e\u003c\/em\u003e'\u003c\/p\u003e\n\u003cp\u003eSolar regulator and wind regulator outputs should be on the high risk '\u003cem\u003e\u003cstrong\u003esolar \/ wind regulator\u003c\/strong\u003e\u003c\/em\u003e' stud\u003c\/p\u003e\n\u003cp\u003e\u003cbr\u003eRefer to the gallery image for a wiring example. \u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e Weight - 300g \u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003eHeight = 90mm | Lenght = 85mm | Width = 90mm\u003c\/p\u003e\n\u003cp\u003eM6 - 6mm bolts\u003c\/p\u003e\n\u003cp\u003epowered from 12V battery \/ 12V system you are protecting - 1mA consumption\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eWhen HVDC12 trips due to a high voltage episode - the RED LED turns on. To reset the relay, simply press the button. The relay shall only re-engage if the voltage is lower than 16V. Please remember, if this relay has tripped please investigate the reasoning for the trip.\u003c\/p\u003e\n\u003cp\u003eThis is not a one time use only product. It can be used time and time again. However, if it is frequently tripping on \/ off - there is like a problem with one of your regulators.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eDesigned, developed and manufactured in England at Sterling Power Products.\u003c\/p\u003e","brand":"Sterling Power Products","offers":[{"title":"Default Title","offer_id":42552271896765,"sku":"HVDC12","price":57.6,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/products\/image1.jpg?v=1671015374"},{"product_id":"vsr-80a-12-24-auto-select","title":"VSR80","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_and_VSR_E_G_F.pdf?488\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_medium.jpg?760\"\u003e  Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003cbr\u003e\u003c\/h4\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_VSR_IFs_76643d9c-e2ec-4525-b79b-f1749c96b582.pdf?762\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_09f43697-3d7a-44fa-8988-8aff196e7ffa_medium.jpg?761\"\u003e Product Information\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePro Connect VSR 80 amp\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDC Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eSize L x W x D mm \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eWeight Kg\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e12 \u0026amp; 24 auto\u003c\/td\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e140 x 180 x 40\u003c\/td\u003e\n\u003ctd\u003e0.1\u003c\/td\u003e\n\u003ctd\u003eVSR80\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive activated relays:\u003c\/strong\u003e\u003cbr\u003eThis product would be regarded as the next level up from the signal feed relay, the main difference being that it is totally automatic - this relay does not require an ignition feed to operate, it works on monitoring the input voltage to the device (usually the starter battery or battery bank with other charging source such as a battery charger or wind gen), when this voltage exceeds 13.3V the processor makes the assumption that the alternator \/ battery charger or other power device is active and as such it will automatically engage the relay to connect the main battery bank to the auxiliary battery bank and so charge the auxiliary battery. Conversely, when the voltage drops below 12.9V the processor in the relay assumes that either the engine has been stopped or the load on the aux battery is pulling the starter battery down too much and for safety reasons it should be isolated. In a nut shell this is easier to install than the above and is smarter, however, it has some of the same limitations as the standard signal relay. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIdeal applications:\u003c\/strong\u003e See signal relay applications. Also ideal for charging a secondary battery bank from a battery charger which has only one output such as combined inverter charger. The starter motor interlock connection prevents the starter motor current being pulled through the relay and damaging the relay.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIts limitations:\u003c\/strong\u003e See the limitations for the signal relay. Another major problem with standard relays is their ability to switch off under high load. The main job of a voltage sensitive relay is to sense any major current being taken out of the starter battery (primary) and to stop it. For example, if we take a typical 12V boat system with an 80A alternator and install a standard 80A VSR on the engine starter battery bank to charge the secondary battery (domestic battery bank, anchor winch or bow thruster battery bank). On engine start up the alternator will raise the voltage on the starter battery and this will engage the relay to charge the secondary battery bank (so far so good). However, for the sake of argument say the secondary battery bank is discharged (i.e. first thing in the morning) and then someone switches on a 2000W inverter, or a bow thruster or the anchor winch, these items will attempt to draw 200A + from the secondary battery bank. However, because the secondary battery is nearly empty, the load (200 amps) will automatically attempt to draw this current from the highest voltage source which, in this case, would be the starter battery bank. Obviously we do not want this to happen as we do not want to drain the starter battery or burn out the 80A relay or even worse set fire to the cables because you are now trying to pull 200A plus down these cables. In theory the large current flow through the VSR will drop the starter battery voltage and so trigger the relay to open circuit and so switch off this circuit stopping the drain and saving the day. However, a relay has 3 main ratings, for example, an 80A relay can take 80A all day no problem, (hence its continuous rating) and has a short term overload of about 400A for about 1\/10th sec. It has a third rating, however, that is much more important; that is the maximum current it can open circuit at. The assumption by the public is that an 80A relay can open circuit at 80A, but that is not so, it has an open circuit current rating of about 30-40A. And so the problem becomes apparent, the high load on the secondary battery system (in the above example) causes an instant load of 200A + on the relay (that's ok, it can deal with this for a split second) then the control circuit attempts to open the relay to stop this discharge, then BANG you open the relay with 200A going through it (with an open circuit rating of about 40 amps) and so you cause a large back E.M.F. If you're lucky, it will vaporise the contacts blowing them in to small pieces and open circuit the relay destroying the product. To reduce this effect, Sterling puts anti back E.M.F. spark reducers on all relay products.\u003cbr\u003eAdjustable: This unit comes factory set to bi-directional activation and can be fitted with no adjustments required to operate as a Voltage sensitive relay straight out of the box, it is auto voltage adjustment so it can be fitted to a 12 or 24V circuit, however, the following things can also be adjusted if desired.\u003cbr\u003e            Unit directional activation:\u003cbr\u003e\u003cstrong\u003eFunction 1:\u003c\/strong\u003e  Charging activated by starter battery voltage increase (engine on). This is the most common setting and the factory default setting. This setting also does not have an ignition feed requirement. This connects the primary and secondary banks based on a voltage in excess of 13.3V being sensed on the primary battery only (the engine starter battery). The 2nd battery bank, once connected would only disconnect when both battery banks drop below 13.0V on both sides. The 13V safety threshold is still activated to protect and seperate the batteries if, or when, the drain that invoked this function (voltage drops below 13V) once the unit has tripped, will not re-engage until the voltage on the primary battery bank (the engine start) has exceeded 13.3V again. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 2: \u003c\/strong\u003e Charging either way (bi directional), based on a voltage rise on either side of the unit (default setting). This function will close the relay at 13.3V sensed on either side of the relay, a good example of this would be the use of a combi inverter charger on the domestic battery bank, because most combi’s only have a single output charging line (to the domestic battery bank) then with this function the unit will charge from the combi to the starter battery bank (in effect giving you 2 outputs from the battery charger) when the combi is on, but also charge from the alternator to the domestic battery bank when the combi is off. In either mode the unit still has the 13.3V on and 13V off mode and the current limit function. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 3: \u003c\/strong\u003e Charging batteries one way only. This function allows a charge to flow from the alternator, or battery to battery charger, or any other charging source to a secondary battery bank, but only when the engine is running. In effect, this mode only allows current flow from the primary source to the secondary, and will continue to flow until either there is an overload threat or a low voltage threat to the primary battery or the engine is shut down. This function requires an extra wire to the unit, an ignition feed, that informs the unit if the engine is running or not.\u003cbr\u003e\u003cstrong\u003eVoltage parameter activation:\u003c\/strong\u003e Voltage activation and deactivation parameters can be adjusted using the setup command.\u003cbr\u003eAuto 12\/24V selection, the unit will auto select the system voltage using the following, if it senses 4 to16V it will lock to 12V , if it sees 16-30V it will lock to 24V. If for some reason the input voltage is very low (in the case of an empty 24V system), then the product can be disconnected and allowed to re-engage,  once locked the product will hold that setting until fully isolated again.\u003cbr\u003eBoth the VSR and the CVSR unit are fitted with the latest active progressive disconnect algorithm to ensure that the batteries can charge even where large differential voltages exist. As such there will be various time delays between what the customer has preset as the turn ‘off’ voltage point and the product actually turning off. The time delay will reduce the lower the voltage is below the programmed disconnect voltage.\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e0.01 volt drop\u003c\/td\u003e\n\u003ctd\u003eIgnition feed (not always required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWaterproof to IP65\u003c\/td\u003e\n\u003ctd\u003eSAEJ1171 ignition protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHigh overload surge rating\u003c\/td\u003e\n\u003ctd\u003eBack EMF spark arrester\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRemote LED connection\u003c\/td\u003e\n\u003ctd\u003eNo ignition feed voltage drop\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuppression diodes across relay to prolong life\u003c\/td\u003e\n\u003ctd\u003eTime delay to prevent engine starter damage\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle \u0026amp; Twin starter motor disengage connections\u003c\/td\u003e\n\u003ctd\u003e12V \u0026amp; 24V automatic selection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eExtremely low quiescent current approx 1 mA\u003c\/td\u003e\n\u003ctd\u003eCustom voltage adjustment parameters available\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eActive progressive disconnect algorithm\u003c\/td\u003e\n\u003ctd\u003eAutomatic voltage activation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAutomatic voltage de activation\u003c\/td\u003e\n\u003ctd\u003eProtects primary battery from discharge\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEmergency auxillary forced activation\u003c\/td\u003e\n\u003ctd\u003eHigh battery voltage trip protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e5 LED information display\u003c\/td\u003e\n\u003ctd\u003e5 alarm functions and safety trips plus information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdjustable relay trigger side operation\u003c\/td\u003e\n\u003ctd\u003eShort circuit protection (prior to engagement)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eWhich model suits my needs best ?\u003c\/strong\u003e\u003cbr\u003e1) The first part is easy, what is the max size of your alternator or charging device. I.e. do you have a 90A alternator or a 100A battery charger charging the primary battery bank. This means that the secondary battery could be subjected to at least that load, so, the relay must be able to comfortably handle that sort of current continuously. It would be wise to give the relay a good 10-20% comfort zone, i.e. always up-size the relay if the charging source and relay are the same, for example, if you have an 80A alternator, combi or battery charger with an 80A relay then go to the 160A relay option to be safe.\u003cbr\u003e\u003cbr\u003e2) Next its cost of installation and ease of installation. If you are fitting the unit and access to ignition feeds is simple then the Ignition Feed system should be entertained, however, if not then the Voltage Sensitive Relay version is much simpler to fit and totally automatic, and has a lot more functions.\u003cbr\u003e\u003cbr\u003e3) Do you need to vary which side of the relay activates the unit, or even ensure the unit is isolated (via ignition feed, or even adjust the standard voltage parameters, all this is possible on the Voltage Sensitive Relay).\u003cbr\u003e\u003cbr\u003e4) The last, but most important aspect is safety. The most important thing here is to establish what the maximum possible load is  that could be placed on the secondary battery bank when the relay is engaged, i.e. a large inverter \/ anchor winch, bow thruster. Remember that every load you put on, the secondary battery will have a percentage of this load transferred to the primary battery depending on how full the secondary battery is. This could range from a few percent to 100 percent, so, it is important that the relay system can deal with this high load without damage. If there are large potential loads such as hundreds of amps then the only way to do this is using a Current Limiting Voltage Sensitive Relay because when exposed to excessive currents, the current limiting models simply and safely shut down until the excessive current is removed, i.e. switched off, then it can automatically re-instate itself and carry on after that large surge load has stopped. This removes the need for excessive cabling and ensures a safe installation with less reliance on fuses for protection.\u003c\/p\u003e","brand":"Sterling Power Product","offers":[{"title":"80 A","offer_id":55893750645110,"sku":"VSR80","price":76.03,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/IMG_6609white_1.jpg?v=1751989828"},{"product_id":"vsr-160a-12v-24v-autoselect","title":"VSR160","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_and_VSR_E_G_F.pdf?488\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_medium.jpg?760\"\u003e  Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003cbr\u003e\u003c\/h4\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_VSR_IFs_76643d9c-e2ec-4525-b79b-f1749c96b582.pdf?762\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_09f43697-3d7a-44fa-8988-8aff196e7ffa_medium.jpg?761\"\u003e Product Information\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePro Connect VSR 160  amp\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDC Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eSize L x W x D mm \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eWeight Kg\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e12 \u0026amp; 24 auto\u003c\/td\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e140 x 190 x 40\u003c\/td\u003e\n\u003ctd\u003e0.2\u003c\/td\u003e\n\u003ctd\u003eVSR160\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive activated relays:\u003c\/strong\u003e\u003cbr\u003eThis product would be regarded as the next level up from the signal feed relay, the main difference being that it is totally automatic - this relay does not require an ignition feed to operate, it works on monitoring the input voltage to the device (usually the starter battery or battery bank with other charging source such as a battery charger or wind gen), when this voltage exceeds 13.3V the processor makes the assumption that the alternator \/ battery charger or other power device is active and as such it will automatically engage the relay to connect the main battery bank to the auxiliary battery bank and so charge the auxiliary battery. Conversely, when the voltage drops below 12.9V the processor in the relay assumes that either the engine has been stopped or the load on the aux battery is pulling the starter battery down too much and for safety reasons it should be isolated. In a nut shell this is easier to install than the above and is smarter, however, it has some of the same limitations as the standard signal relay. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIdeal applications:\u003c\/strong\u003e See signal relay applications. Also ideal for charging a secondary battery bank from a battery charger which has only one output such as combined inverter charger. The starter motor interlock connection prevents the starter motor current being pulled through the relay and damaging the relay.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIts limitations:\u003c\/strong\u003e See the limitations for the signal relay. Another major problem with standard relays is their ability to switch off under high load. The main job of a voltage sensitive relay is to sense any major current being taken out of the starter battery (primary) and to stop it. For example, if we take a typical 12V boat system with an 80A alternator and install a standard 80A VSR on the engine starter battery bank to charge the secondary battery (domestic battery bank, anchor winch or bow thruster battery bank). On engine start up the alternator will raise the voltage on the starter battery and this will engage the relay to charge the secondary battery bank (so far so good). However, for the sake of argument say the secondary battery bank is discharged (i.e. first thing in the morning) and then someone switches on a 2000W inverter, or a bow thruster or the anchor winch, these items will attempt to draw 200A + from the secondary battery bank. However, because the secondary battery is nearly empty, the load (200 amps) will automatically attempt to draw this current from the highest voltage source which, in this case, would be the starter battery bank. Obviously we do not want this to happen as we do not want to drain the starter battery or burn out the 80A relay or even worse set fire to the cables because you are now trying to pull 200A plus down these cables. In theory the large current flow through the VSR will drop the starter battery voltage and so trigger the relay to open circuit and so switch off this circuit stopping the drain and saving the day. However, a relay has 3 main ratings, for example, an 80A relay can take 80A all day no problem, (hence its continuous rating) and has a short term overload of about 400A for about 1\/10th sec. It has a third rating, however, that is much more important; that is the maximum current it can open circuit at. The assumption by the public is that an 80A relay can open circuit at 80A, but that is not so, it has an open circuit current rating of about 30-40A. And so the problem becomes apparent, the high load on the secondary battery system (in the above example) causes an instant load of 200A + on the relay (that's ok, it can deal with this for a split second) then the control circuit attempts to open the relay to stop this discharge, then BANG you open the relay with 200A going through it (with an open circuit rating of about 40 amps) and so you cause a large back E.M.F. If you're lucky, it will vaporise the contacts blowing them in to small pieces and open circuit the relay destroying the product. To reduce this effect, Sterling puts anti back E.M.F. spark reducers on all relay products.\u003cbr\u003eAdjustable: This unit comes factory set to bi-directional activation and can be fitted with no adjustments required to operate as a Voltage sensitive relay straight out of the box, it is auto voltage adjustment so it can be fitted to a 12 or 24V circuit, however, the following things can also be adjusted if desired.\u003cbr\u003e            Unit directional activation:\u003cbr\u003e\u003cstrong\u003eFunction 1:\u003c\/strong\u003e  Charging activated by starter battery voltage increase (engine on). This is the most common setting and the factory default setting. This setting also does not have an ignition feed requirement. This connects the primary and secondary banks based on a voltage in excess of 13.3V being sensed on the primary battery only (the engine starter battery). The 2nd battery bank, once connected would only disconnect when both battery banks drop below 13.0V on both sides. The 13V safety threshold is still activated to protect and seperate the batteries if, or when, the drain that invoked this function (voltage drops below 13V) once the unit has tripped, will not re-engage until the voltage on the primary battery bank (the engine start) has exceeded 13.3V again. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 2: \u003c\/strong\u003e Charging either way (bi directional), based on a voltage rise on either side of the unit (default setting). This function will close the relay at 13.3V sensed on either side of the relay, a good example of this would be the use of a combi inverter charger on the domestic battery bank, because most combi’s only have a single output charging line (to the domestic battery bank) then with this function the unit will charge from the combi to the starter battery bank (in effect giving you 2 outputs from the battery charger) when the combi is on, but also charge from the alternator to the domestic battery bank when the combi is off. In either mode the unit still has the 13.3V on and 13V off mode and the current limit function. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 3: \u003c\/strong\u003e Charging batteries one way only. This function allows a charge to flow from the alternator, or battery to battery charger, or any other charging source to a secondary battery bank, but only when the engine is running. In effect, this mode only allows current flow from the primary source to the secondary, and will continue to flow until either there is an overload threat or a low voltage threat to the primary battery or the engine is shut down. This function requires an extra wire to the unit, an ignition feed, that informs the unit if the engine is running or not.\u003cbr\u003e\u003cstrong\u003eVoltage parameter activation:\u003c\/strong\u003e Voltage activation and deactivation parameters can be adjusted using the setup command.\u003cbr\u003eAuto 12\/24V selection, the unit will auto select the system voltage using the following, if it senses 4 to16V it will lock to 12V , if it sees 16-30V it will lock to 24V. If for some reason the input voltage is very low (in the case of an empty 24V system), then the product can be disconnected and allowed to re-engage,  once locked the product will hold that setting until fully isolated again.\u003cbr\u003eBoth the VSR and the CVSR unit are fitted with the latest active progressive disconnect algorithm to ensure that the batteries can charge even where large differential voltages exist. As such there will be various time delays between what the customer has preset as the turn ‘off’ voltage point and the product actually turning off. The time delay will reduce the lower the voltage is below the programmed disconnect voltage.\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e0.01 volt drop\u003c\/td\u003e\n\u003ctd\u003eIgnition feed (not always required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWaterproof to IP65\u003c\/td\u003e\n\u003ctd\u003eSAEJ1171 ignition protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHigh overload surge rating\u003c\/td\u003e\n\u003ctd\u003eBack EMF spark arrester\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRemote LED connection\u003c\/td\u003e\n\u003ctd\u003eNo ignition feed voltage drop\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuppression diodes across relay to prolong life\u003c\/td\u003e\n\u003ctd\u003eTime delay to prevent engine starter damage\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle \u0026amp; Twin starter motor disengage connections\u003c\/td\u003e\n\u003ctd\u003e12V \u0026amp; 24V automatic selection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eExtremely low quiescent current approx 1 mA\u003c\/td\u003e\n\u003ctd\u003eCustom voltage adjustment parameters available\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eActive progressive disconnect algorithm\u003c\/td\u003e\n\u003ctd\u003eAutomatic voltage activation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAutomatic voltage de activation\u003c\/td\u003e\n\u003ctd\u003eProtects primary battery from discharge\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEmergency auxillary forced activation\u003c\/td\u003e\n\u003ctd\u003eHigh battery voltage trip protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e5 LED information display\u003c\/td\u003e\n\u003ctd\u003e5 alarm functions and safety trips plus information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdjustable relay trigger side operation\u003c\/td\u003e\n\u003ctd\u003eShort circuit protection (prior to engagement)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eWhich model suits my needs best ?\u003c\/strong\u003e\u003cbr\u003e1) The first part is easy, what is the max size of your alternator or charging device. I.e. do you have a 90A alternator or a 100A battery charger charging the primary battery bank. This means that the secondary battery could be subjected to at least that load, so, the relay must be able to comfortably handle that sort of current continuously. It would be wise to give the relay a good 10-20% comfort zone, i.e. always up-size the relay if the charging source and relay are the same, for example, if you have an 80A alternator, combi or battery charger with an 80A relay then go to the 160A relay option to be safe.\u003cbr\u003e\u003cbr\u003e2) Next its cost of installation and ease of installation. If you are fitting the unit and access to ignition feeds is simple then the Ignition Feed system should be entertained, however, if not then the Voltage Sensitive Relay version is much simpler to fit and totally automatic, and has a lot more functions.\u003cbr\u003e\u003cbr\u003e3) Do you need to vary which side of the relay activates the unit, or even ensure the unit is isolated (via ignition feed, or even adjust the standard voltage parameters, all this is possible on the Voltage Sensitive Relay).\u003cbr\u003e\u003cbr\u003e4) The last, but most important aspect is safety. The most important thing here is to establish what the maximum possible load is  that could be placed on the secondary battery bank when the relay is engaged, i.e. a large inverter \/ anchor winch, bow thruster. Remember that every load you put on, the secondary battery will have a percentage of this load transferred to the primary battery depending on how full the secondary battery is. This could range from a few percent to 100 percent, so, it is important that the relay system can deal with this high load without damage. If there are large potential loads such as hundreds of amps then the only way to do this is using a Current Limiting Voltage Sensitive Relay because when exposed to excessive currents, the current limiting models simply and safely shut down until the excessive current is removed, i.e. switched off, then it can automatically re-instate itself and carry on after that large surge load has stopped. This removes the need for excessive cabling and ensures a safe installation with less reliance on fuses for protection.\u003c\/p\u003e","brand":"Sterling Power Product","offers":[{"title":"160 A","offer_id":55893751431542,"sku":"VSR160","price":86.17,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/IMG_6609white_1.jpg?v=1751989828"},{"product_id":"vsr-240a-12v-24v-autoselect","title":"VSR240","description":"\u003ctable width=\"100%\" style=\"width: 100%;\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 51.448%;\"\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_and_VSR_E_G_F.pdf?488\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_medium.jpg?760\"\u003e  Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd style=\"width: 48.2112%;\"\u003e\n\u003ch4\u003e\u003cbr\u003e\u003c\/h4\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_VSR_IFs_76643d9c-e2ec-4525-b79b-f1749c96b582.pdf?762\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/CVSR_09f43697-3d7a-44fa-8988-8aff196e7ffa_medium.jpg?761\"\u003e Product Information\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003ePro Connect VSR  240 amp\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eDC Voltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eSize L x W x D mm \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eWeight Kg\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e12 \u0026amp; 24 auto\u003c\/td\u003e\n\u003ctd\u003e240\u003c\/td\u003e\n\u003ctd\u003e140 x 200 x 40\u003c\/td\u003e\n\u003ctd\u003e0.25\u003c\/td\u003e\n\u003ctd\u003eVSR240\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive activated relays:\u003c\/strong\u003e\u003cbr\u003eThis product would be regarded as the next level up from the signal feed relay, the main difference being that it is totally automatic - this relay does not require an ignition feed to operate, it works on monitoring the input voltage to the device (usually the starter battery or battery bank with other charging source such as a battery charger or wind gen), when this voltage exceeds 13.3V the processor makes the assumption that the alternator \/ battery charger or other power device is active and as such it will automatically engage the relay to connect the main battery bank to the auxiliary battery bank and so charge the auxiliary battery. Conversely, when the voltage drops below 12.9V the processor in the relay assumes that either the engine has been stopped or the load on the aux battery is pulling the starter battery down too much and for safety reasons it should be isolated. In a nut shell this is easier to install than the above and is smarter, however, it has some of the same limitations as the standard signal relay. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIdeal applications:\u003c\/strong\u003e See signal relay applications. Also ideal for charging a secondary battery bank from a battery charger which has only one output such as combined inverter charger. The starter motor interlock connection prevents the starter motor current being pulled through the relay and damaging the relay.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eIts limitations:\u003c\/strong\u003e See the limitations for the signal relay. Another major problem with standard relays is their ability to switch off under high load. The main job of a voltage sensitive relay is to sense any major current being taken out of the starter battery (primary) and to stop it. For example, if we take a typical 12V boat system with an 80A alternator and install a standard 80A VSR on the engine starter battery bank to charge the secondary battery (domestic battery bank, anchor winch or bow thruster battery bank). On engine start up the alternator will raise the voltage on the starter battery and this will engage the relay to charge the secondary battery bank (so far so good). However, for the sake of argument say the secondary battery bank is discharged (i.e. first thing in the morning) and then someone switches on a 2000W inverter, or a bow thruster or the anchor winch, these items will attempt to draw 200A + from the secondary battery bank. However, because the secondary battery is nearly empty, the load (200 amps) will automatically attempt to draw this current from the highest voltage source which, in this case, would be the starter battery bank. Obviously we do not want this to happen as we do not want to drain the starter battery or burn out the 80A relay or even worse set fire to the cables because you are now trying to pull 200A plus down these cables. In theory the large current flow through the VSR will drop the starter battery voltage and so trigger the relay to open circuit and so switch off this circuit stopping the drain and saving the day. However, a relay has 3 main ratings, for example, an 80A relay can take 80A all day no problem, (hence its continuous rating) and has a short term overload of about 400A for about 1\/10th sec. It has a third rating, however, that is much more important; that is the maximum current it can open circuit at. The assumption by the public is that an 80A relay can open circuit at 80A, but that is not so, it has an open circuit current rating of about 30-40A. And so the problem becomes apparent, the high load on the secondary battery system (in the above example) causes an instant load of 200A + on the relay (that's ok, it can deal with this for a split second) then the control circuit attempts to open the relay to stop this discharge, then BANG you open the relay with 200A going through it (with an open circuit rating of about 40 amps) and so you cause a large back E.M.F. If you're lucky, it will vaporise the contacts blowing them in to small pieces and open circuit the relay destroying the product. To reduce this effect, Sterling puts anti back E.M.F. spark reducers on all relay products.\u003cbr\u003eAdjustable: This unit comes factory set to bi-directional activation and can be fitted with no adjustments required to operate as a Voltage sensitive relay straight out of the box, it is auto voltage adjustment so it can be fitted to a 12 or 24V circuit, however, the following things can also be adjusted if desired.\u003cbr\u003e            Unit directional activation:\u003cbr\u003e\u003cstrong\u003eFunction 1:\u003c\/strong\u003e  Charging activated by starter battery voltage increase (engine on). This is the most common setting and the factory default setting. This setting also does not have an ignition feed requirement. This connects the primary and secondary banks based on a voltage in excess of 13.3V being sensed on the primary battery only (the engine starter battery). The 2nd battery bank, once connected would only disconnect when both battery banks drop below 13.0V on both sides. The 13V safety threshold is still activated to protect and seperate the batteries if, or when, the drain that invoked this function (voltage drops below 13V) once the unit has tripped, will not re-engage until the voltage on the primary battery bank (the engine start) has exceeded 13.3V again. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 2: \u003c\/strong\u003e Charging either way (bi directional), based on a voltage rise on either side of the unit (default setting). This function will close the relay at 13.3V sensed on either side of the relay, a good example of this would be the use of a combi inverter charger on the domestic battery bank, because most combi’s only have a single output charging line (to the domestic battery bank) then with this function the unit will charge from the combi to the starter battery bank (in effect giving you 2 outputs from the battery charger) when the combi is on, but also charge from the alternator to the domestic battery bank when the combi is off. In either mode the unit still has the 13.3V on and 13V off mode and the current limit function. No ignition feed required on this setting.\u003cbr\u003e\u003cstrong\u003eFunction 3: \u003c\/strong\u003e Charging batteries one way only. This function allows a charge to flow from the alternator, or battery to battery charger, or any other charging source to a secondary battery bank, but only when the engine is running. In effect, this mode only allows current flow from the primary source to the secondary, and will continue to flow until either there is an overload threat or a low voltage threat to the primary battery or the engine is shut down. This function requires an extra wire to the unit, an ignition feed, that informs the unit if the engine is running or not.\u003cbr\u003e\u003cstrong\u003eVoltage parameter activation:\u003c\/strong\u003e Voltage activation and deactivation parameters can be adjusted using the setup command.\u003cbr\u003eAuto 12\/24V selection, the unit will auto select the system voltage using the following, if it senses 4 to16V it will lock to 12V , if it sees 16-30V it will lock to 24V. If for some reason the input voltage is very low (in the case of an empty 24V system), then the product can be disconnected and allowed to re-engage,  once locked the product will hold that setting until fully isolated again.\u003cbr\u003eBoth the VSR and the CVSR unit are fitted with the latest active progressive disconnect algorithm to ensure that the batteries can charge even where large differential voltages exist. As such there will be various time delays between what the customer has preset as the turn ‘off’ voltage point and the product actually turning off. The time delay will reduce the lower the voltage is below the programmed disconnect voltage.\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e0.01 volt drop\u003c\/td\u003e\n\u003ctd\u003eIgnition feed (not always required)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWaterproof to IP65\u003c\/td\u003e\n\u003ctd\u003eSAEJ1171 ignition protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eHigh overload surge rating\u003c\/td\u003e\n\u003ctd\u003eBack EMF spark arrester\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRemote LED connection\u003c\/td\u003e\n\u003ctd\u003eNo ignition feed voltage drop\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSuppression diodes across relay to prolong life\u003c\/td\u003e\n\u003ctd\u003eTime delay to prevent engine starter damage\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSingle \u0026amp; Twin starter motor disengage connections\u003c\/td\u003e\n\u003ctd\u003e12V \u0026amp; 24V automatic selection\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eExtremely low quiescent current approx 1 mA\u003c\/td\u003e\n\u003ctd\u003eCustom voltage adjustment parameters available\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eActive progressive disconnect algorithm\u003c\/td\u003e\n\u003ctd\u003eAutomatic voltage activation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAutomatic voltage de activation\u003c\/td\u003e\n\u003ctd\u003eProtects primary battery from discharge\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eEmergency auxillary forced activation\u003c\/td\u003e\n\u003ctd\u003eHigh battery voltage trip protected\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e5 LED information display\u003c\/td\u003e\n\u003ctd\u003e5 alarm functions and safety trips plus information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAdjustable relay trigger side operation\u003c\/td\u003e\n\u003ctd\u003eShort circuit protection (prior to engagement)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eWhich model suits my needs best ?\u003c\/strong\u003e\u003cbr\u003e1) The first part is easy, what is the max size of your alternator or charging device. I.e. do you have a 90A alternator or a 100A battery charger charging the primary battery bank. This means that the secondary battery could be subjected to at least that load, so, the relay must be able to comfortably handle that sort of current continuously. It would be wise to give the relay a good 10-20% comfort zone, i.e. always up-size the relay if the charging source and relay are the same, for example, if you have an 80A alternator, combi or battery charger with an 80A relay then go to the 160A relay option to be safe.\u003cbr\u003e\u003cbr\u003e2) Next its cost of installation and ease of installation. If you are fitting the unit and access to ignition feeds is simple then the Ignition Feed system should be entertained, however, if not then the Voltage Sensitive Relay version is much simpler to fit and totally automatic, and has a lot more functions.\u003cbr\u003e\u003cbr\u003e3) Do you need to vary which side of the relay activates the unit, or even ensure the unit is isolated (via ignition feed, or even adjust the standard voltage parameters, all this is possible on the Voltage Sensitive Relay).\u003cbr\u003e\u003cbr\u003e4) The last, but most important aspect is safety. The most important thing here is to establish what the maximum possible load is  that could be placed on the secondary battery bank when the relay is engaged, i.e. a large inverter \/ anchor winch, bow thruster. Remember that every load you put on, the secondary battery will have a percentage of this load transferred to the primary battery depending on how full the secondary battery is. This could range from a few percent to 100 percent, so, it is important that the relay system can deal with this high load without damage. If there are large potential loads such as hundreds of amps then the only way to do this is using a Current Limiting Voltage Sensitive Relay because when exposed to excessive currents, the current limiting models simply and safely shut down until the excessive current is removed, i.e. switched off, then it can automatically re-instate itself and carry on after that large surge load has stopped. This removes the need for excessive cabling and ensures a safe installation with less reliance on fuses for protection.\u003c\/p\u003e","brand":"Sterling Power Product","offers":[{"title":"240 A","offer_id":55893754118518,"sku":"VSR240","price":103.91,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/IMG_6609white_1.jpg?v=1751989828"},{"product_id":"12v-80a-vsra8012","title":"VSRA8012","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_ins_eng_ger_fren_348fbc80-b7a0-4f91-afd3-add8fae2a781.pdf?491\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_a5a459c2-fe25-4183-9703-f70f261a5d4c_medium.jpg?2851008086890650313\"\u003e Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003cbr\u003e\u003c\/h4\u003e\n\u003ch4\u003e\n\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRs_medium.jpg?924\"\u003e\u003c\/a\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e Product Information PDF\u003c\/a\u003e\n\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive Relay Analogue Fixed Programme\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eContinuous Current \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eOverload Ability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e12\u003c\/td\u003e\n\u003ctd\u003e80 amps\u003c\/td\u003e\n\u003ctd\u003e200 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA8012\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage sensitive relay analogue vs digital\u003c\/strong\u003e\u003cbr\u003eThere are 2 main types of voltage sensitive relays on the market, by far the most common is the lower cost analogue  model (The Sterling analogue model has the added advantage of 8 mm stud connectors and IP68 rating), (fully waterproof), this type of device is very basic and simply switches on and off between two preset voltages with a 40 or so second time delay. This product works fine for the majority of installations where the second battery banks is only being charged when the engine is running and there is no real current drawn from the second battery set while the vehicle is on the move, ideal for most vehicle operation, however, things get more complex where there is current being drawn while the engine (on a boat or while a vehicle is not moving but the engine is running) or the batteries are the more exotic batteries such as AGM are being used (where different voltage switching is required) then the limitations of the analogue (no adjustable aspect) unit can be over come with the more expensive but much more controllable digital unit. The digital unit offers the operator a wide switching voltage range to chose from ensuring the open circuit voltage is above the discharge voltages of AGM, Gel and lithium, also the unit’s bi-directional features may be required, and last but by no means least a switching algorithms is used to prevent unnecessary switching of the relay.  Also, because a digital unit is active all the time the quiescent current of the product is vital, i.e. the current it takes to run the product, in the case of the Sterling is less than 1 mA that’s 0.001A which is about 1A per week usage. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhy would I want to adjust a voltage sensitive relay?\u003c\/strong\u003e\u003cbr\u003e1) Most Analogue VSRs come preset (for 24V x 2) to engage at 13.3V and disengage about 12.8V. Where as this is ok for normal lead acid batteries an AGM, Gel and Lithium battery have a much higher surface which will require adjustment voltages as high as 13V, this makes standard relay settings incorrect and will require the thresholds to be adjusted up. Batteries would be partially discharged at this voltage and would require switching off at about 13.2V. This could not be achieved with a fixed analogue model but there is no problem with the digital.\u003cbr\u003e2) Directional control, Most analogue VSRs are preset as Bi-directional activation, i.e. if either the second battery or the first battery reaches the required trigger voltage the unit will work, however, there are times when the system wants to have the unit activated from the first battery but not activated from the secondary battery, this is called unidirectional, the digital version can do this.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eDigital\u003c\/strong\u003e\u003cbr\u003eThe digital unit has a unique built in magnetic program ability, the lid of the unit has an in built magnet and the unit has an internal reed switch to pick up the magnets pulse generated by the user when the unit requires reprogramming this allows the product to be totally programmable by the lid but still maintained the waterproof integrity.  \u003cbr\u003e \u003cbr\u003eThis unit is fitted with the latest on\/off algorithms to prevent unnecessary switching, and has an extremely low quiescent current of less than 1 mA \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhat size of relay do I require?\u003c\/strong\u003e\u003cbr\u003eTo match a relay to your system the important things are \u003cbr\u003e1) Ensure the amp ratings of the relay 10 - 20 % is larger than the largest charging source.\u003cbr\u003e2) Ensure no load on the secondary battery bank exceeds the rating of the relay when on.\u003cbr\u003eIn the event of having a large load such as a 2000W + inverter, anchor winch or bow thruster then please look at our range of Current Limiting Voltage sensitive relays to deal with these high loads. \u003cbr\u003eIf the relay is to be used on a battery bank with a solar cell which is required to charge other batteries when the engine\/battery charger is off then please look at the Latching Relay products, as this is more suitable for that operation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFeatures of the Analogue VSR\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eIP66 Waterproof\u003c\/td\u003e\n\u003ctd\u003eFixed voltage switching\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFixed time switching delay\u003c\/td\u003e\n\u003ctd\u003e12 or 24V unit only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnti relay contact arching protection\u003c\/td\u003e\n\u003ctd\u003eHigh quality brass connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelay electrical override ability\u003c\/td\u003e\n\u003ctd\u003e1 LED active information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBi directional operation only\u003c\/td\u003e\n\u003ctd\u003e\u003cbr\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Sterling Power Products","offers":[{"title":"12V 80A","offer_id":55986683838838,"sku":"VSRA8012","price":86.4,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/IMG_6729white.jpg?v=1753376148"},{"product_id":"12v-160a-vsra16012","title":"VSRA16012","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_ins_eng_ger_fren_348fbc80-b7a0-4f91-afd3-add8fae2a781.pdf?491\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_a5a459c2-fe25-4183-9703-f70f261a5d4c_medium.jpg?2851008086890650313\"\u003e Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003cbr\u003e\u003c\/h4\u003e\n\u003ch4\u003e\n\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRs_medium.jpg?924\"\u003e\u003c\/a\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e Product Information PDF\u003c\/a\u003e\n\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive Relay Analogue Fixed Programme\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eContinuous Current \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eOverload Ability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e12\u003c\/td\u003e\n\u003ctd\u003e160 amps\u003c\/td\u003e\n\u003ctd\u003e400 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA16012\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage sensitive relay analogue vs digital\u003c\/strong\u003e\u003cbr\u003eThere are 2 main types of voltage sensitive relays on the market, by far the most common is the lower cost analogue  model (The Sterling analogue model has the added advantage of 8 mm stud connectors and IP68 rating), (fully waterproof), this type of device is very basic and simply switches on and off between two preset voltages with a 40 or so second time delay. This product works fine for the majority of installations where the second battery banks is only being charged when the engine is running and there is no real current drawn from the second battery set while the vehicle is on the move, ideal for most vehicle operation, however, things get more complex where there is current being drawn while the engine (on a boat or while a vehicle is not moving but the engine is running) or the batteries are the more exotic batteries such as AGM are being used (where different voltage switching is required) then the limitations of the analogue (no adjustable aspect) unit can be over come with the more expensive but much more controllable digital unit. The digital unit offers the operator a wide switching voltage range to chose from ensuring the open circuit voltage is above the discharge voltages of AGM, Gel and lithium, also the unit’s bi-directional features may be required, and last but by no means least a switching algorithms is used to prevent unnecessary switching of the relay.  Also, because a digital unit is active all the time the quiescent current of the product is vital, i.e. the current it takes to run the product, in the case of the Sterling is less than 1 mA that’s 0.001A which is about 1A per week usage. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhy would I want to adjust a voltage sensitive relay?\u003c\/strong\u003e\u003cbr\u003e1) Most Analogue VSRs come preset (for 24V x 2) to engage at 13.3V and disengage about 12.8V. Where as this is ok for normal lead acid batteries an AGM, Gel and Lithium battery have a much higher surface which will require adjustment voltages as high as 13V, this makes standard relay settings incorrect and will require the thresholds to be adjusted up. Batteries would be partially discharged at this voltage and would require switching off at about 13.2V. This could not be achieved with a fixed analogue model but there is no problem with the digital.\u003cbr\u003e2) Directional control, Most analogue VSRs are preset as Bi-directional activation, i.e. if either the second battery or the first battery reaches the required trigger voltage the unit will work, however, there are times when the system wants to have the unit activated from the first battery but not activated from the secondary battery, this is called unidirectional, the digital version can do this.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eDigital\u003c\/strong\u003e\u003cbr\u003eThe digital unit has a unique built in magnetic program ability, the lid of the unit has an in built magnet and the unit has an internal reed switch to pick up the magnets pulse generated by the user when the unit requires reprogramming this allows the product to be totally programmable by the lid but still maintained the waterproof integrity.  \u003cbr\u003e \u003cbr\u003eThis unit is fitted with the latest on\/off algorithms to prevent unnecessary switching, and has an extremely low quiescent current of less than 1 mA \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhat size of relay do I require?\u003c\/strong\u003e\u003cbr\u003eTo match a relay to your system the important things are \u003cbr\u003e1) Ensure the amp ratings of the relay 10 - 20 % is larger than the largest charging source.\u003cbr\u003e2) Ensure no load on the secondary battery bank exceeds the rating of the relay when on.\u003cbr\u003eIn the event of having a large load such as a 2000W + inverter, anchor winch or bow thruster then please look at our range of Current Limiting Voltage sensitive relays to deal with these high loads. \u003cbr\u003eIf the relay is to be used on a battery bank with a solar cell which is required to charge other batteries when the engine\/battery charger is off then please look at the Latching Relay products, as this is more suitable for that operation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFeatures of the Analogue VSR\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eIP66 Waterproof\u003c\/td\u003e\n\u003ctd\u003eFixed voltage switching\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFixed time switching delay\u003c\/td\u003e\n\u003ctd\u003e12 or 24V unit only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnti relay contact arching protection\u003c\/td\u003e\n\u003ctd\u003eHigh quality brass connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelay electrical override ability\u003c\/td\u003e\n\u003ctd\u003e1 LED active information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBi directional operation only\u003c\/td\u003e\n\u003ctd\u003e\u003cbr\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Sterling Power Products","offers":[{"title":"12V 160A","offer_id":55986687312246,"sku":"VSRA16012","price":96.0,"currency_code":"GBP","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/IMG_6729white.jpg?v=1753376148"},{"product_id":"24v-160a-vsra16024","title":"VSRA16024","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_ins_eng_ger_fren_348fbc80-b7a0-4f91-afd3-add8fae2a781.pdf?491\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_a5a459c2-fe25-4183-9703-f70f261a5d4c_medium.jpg?2851008086890650313\"\u003e Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003cbr\u003e\u003c\/h4\u003e\n\u003ch4\u003e\n\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRs_medium.jpg?924\"\u003e\u003c\/a\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e Product Information PDF\u003c\/a\u003e\n\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive Relay Analogue Fixed Programme\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eContinuous Current \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eOverload Ability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e160\u003c\/td\u003e\n\u003ctd\u003e24\u003c\/td\u003e\n\u003ctd\u003e160 amps\u003c\/td\u003e\n\u003ctd\u003e400 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA16024\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage sensitive relay analogue vs digital\u003c\/strong\u003e\u003cbr\u003eThere are 2 main types of voltage sensitive relays on the market, by far the most common is the lower cost analogue  model (The Sterling analogue model has the added advantage of 8 mm stud connectors and IP68 rating), (fully waterproof), this type of device is very basic and simply switches on and off between two preset voltages with a 40 or so second time delay. This product works fine for the majority of installations where the second battery banks is only being charged when the engine is running and there is no real current drawn from the second battery set while the vehicle is on the move, ideal for most vehicle operation, however, things get more complex where there is current being drawn while the engine (on a boat or while a vehicle is not moving but the engine is running) or the batteries are the more exotic batteries such as AGM are being used (where different voltage switching is required) then the limitations of the analogue (no adjustable aspect) unit can be over come with the more expensive but much more controllable digital unit. The digital unit offers the operator a wide switching voltage range to chose from ensuring the open circuit voltage is above the discharge voltages of AGM, Gel and lithium, also the unit’s bi-directional features may be required, and last but by no means least a switching algorithms is used to prevent unnecessary switching of the relay.  Also, because a digital unit is active all the time the quiescent current of the product is vital, i.e. the current it takes to run the product, in the case of the Sterling is less than 1 mA that’s 0.001A which is about 1A per week usage. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhy would I want to adjust a voltage sensitive relay?\u003c\/strong\u003e\u003cbr\u003e1) Most Analogue VSRs come preset (for 24V x 2) to engage at 13.3V and disengage about 12.8V. Where as this is ok for normal lead acid batteries an AGM, Gel and Lithium battery have a much higher surface which will require adjustment voltages as high as 13V, this makes standard relay settings incorrect and will require the thresholds to be adjusted up. Batteries would be partially discharged at this voltage and would require switching off at about 13.2V. This could not be achieved with a fixed analogue model but there is no problem with the digital.\u003cbr\u003e2) Directional control, Most analogue VSRs are preset as Bi-directional activation, i.e. if either the second battery or the first battery reaches the required trigger voltage the unit will work, however, there are times when the system wants to have the unit activated from the first battery but not activated from the secondary battery, this is called unidirectional, the digital version can do this.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eDigital\u003c\/strong\u003e\u003cbr\u003eThe digital unit has a unique built in magnetic program ability, the lid of the unit has an in built magnet and the unit has an internal reed switch to pick up the magnets pulse generated by the user when the unit requires reprogramming this allows the product to be totally programmable by the lid but still maintained the waterproof integrity.  \u003cbr\u003e \u003cbr\u003eThis unit is fitted with the latest on\/off algorithms to prevent unnecessary switching, and has an extremely low quiescent current of less than 1 mA \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhat size of relay do I require?\u003c\/strong\u003e\u003cbr\u003eTo match a relay to your system the important things are \u003cbr\u003e1) Ensure the amp ratings of the relay 10 - 20 % is larger than the largest charging source.\u003cbr\u003e2) Ensure no load on the secondary battery bank exceeds the rating of the relay when on.\u003cbr\u003eIn the event of having a large load such as a 2000W + inverter, anchor winch or bow thruster then please look at our range of Current Limiting Voltage sensitive relays to deal with these high loads. \u003cbr\u003eIf the relay is to be used on a battery bank with a solar cell which is required to charge other batteries when the engine\/battery charger is off then please look at the Latching Relay products, as this is more suitable for that operation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFeatures of the Analogue VSR\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eIP66 Waterproof\u003c\/td\u003e\n\u003ctd\u003eFixed voltage switching\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFixed time switching delay\u003c\/td\u003e\n\u003ctd\u003e12 or 24V unit only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnti relay contact arching protection\u003c\/td\u003e\n\u003ctd\u003eHigh quality brass connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelay electrical override ability\u003c\/td\u003e\n\u003ctd\u003e1 LED active information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBi directional operation only\u003c\/td\u003e\n\u003ctd\u003e\u003cbr\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Sterling Power Products","offers":[{"title":"24V 160A","offer_id":55986688393590,"sku":"VSRA16024","price":96.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/IMG_6729white.jpg?v=1753376148"},{"product_id":"24v-80a-vsra8024","title":"VSRA8024","description":"\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_ins_eng_ger_fren_348fbc80-b7a0-4f91-afd3-add8fae2a781.pdf?491\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRA_a5a459c2-fe25-4183-9703-f70f261a5d4c_medium.jpg?2851008086890650313\"\u003e Instruction Manual PDF\u003c\/a\u003e\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003ch4\u003e\u003cbr\u003e\u003c\/h4\u003e\n\u003ch4\u003e\n\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/VSRs_medium.jpg?924\"\u003e\u003c\/a\u003e\u003ca rel=\"noopener noreferrer\" href=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/Page27_VSR_IF_05aafb48-6bec-423b-8be7-54430f56cade.pdf?925\" target=\"_blank\"\u003e Product Information PDF\u003c\/a\u003e\n\u003c\/h4\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage Sensitive Relay Analogue Fixed Programme\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eAmps\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eVoltage\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eContinuous Current \u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eOverload Ability\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003ePart Number\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e80\u003c\/td\u003e\n\u003ctd\u003e24\u003c\/td\u003e\n\u003ctd\u003e80 amps\u003c\/td\u003e\n\u003ctd\u003e200 amps\u003c\/td\u003e\n\u003ctd\u003eVSRA8024\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVoltage sensitive relay analogue vs digital\u003c\/strong\u003e\u003cbr\u003eThere are 2 main types of voltage sensitive relays on the market, by far the most common is the lower cost analogue  model (The Sterling analogue model has the added advantage of 8 mm stud connectors and IP68 rating), (fully waterproof), this type of device is very basic and simply switches on and off between two preset voltages with a 40 or so second time delay. This product works fine for the majority of installations where the second battery banks is only being charged when the engine is running and there is no real current drawn from the second battery set while the vehicle is on the move, ideal for most vehicle operation, however, things get more complex where there is current being drawn while the engine (on a boat or while a vehicle is not moving but the engine is running) or the batteries are the more exotic batteries such as AGM are being used (where different voltage switching is required) then the limitations of the analogue (no adjustable aspect) unit can be over come with the more expensive but much more controllable digital unit. The digital unit offers the operator a wide switching voltage range to chose from ensuring the open circuit voltage is above the discharge voltages of AGM, Gel and lithium, also the unit’s bi-directional features may be required, and last but by no means least a switching algorithms is used to prevent unnecessary switching of the relay.  Also, because a digital unit is active all the time the quiescent current of the product is vital, i.e. the current it takes to run the product, in the case of the Sterling is less than 1 mA that’s 0.001A which is about 1A per week usage. \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhy would I want to adjust a voltage sensitive relay?\u003c\/strong\u003e\u003cbr\u003e1) Most Analogue VSRs come preset (for 24V x 2) to engage at 13.3V and disengage about 12.8V. Where as this is ok for normal lead acid batteries an AGM, Gel and Lithium battery have a much higher surface which will require adjustment voltages as high as 13V, this makes standard relay settings incorrect and will require the thresholds to be adjusted up. Batteries would be partially discharged at this voltage and would require switching off at about 13.2V. This could not be achieved with a fixed analogue model but there is no problem with the digital.\u003cbr\u003e2) Directional control, Most analogue VSRs are preset as Bi-directional activation, i.e. if either the second battery or the first battery reaches the required trigger voltage the unit will work, however, there are times when the system wants to have the unit activated from the first battery but not activated from the secondary battery, this is called unidirectional, the digital version can do this.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eDigital\u003c\/strong\u003e\u003cbr\u003eThe digital unit has a unique built in magnetic program ability, the lid of the unit has an in built magnet and the unit has an internal reed switch to pick up the magnets pulse generated by the user when the unit requires reprogramming this allows the product to be totally programmable by the lid but still maintained the waterproof integrity.  \u003cbr\u003e \u003cbr\u003eThis unit is fitted with the latest on\/off algorithms to prevent unnecessary switching, and has an extremely low quiescent current of less than 1 mA \u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eWhat size of relay do I require?\u003c\/strong\u003e\u003cbr\u003eTo match a relay to your system the important things are \u003cbr\u003e1) Ensure the amp ratings of the relay 10 - 20 % is larger than the largest charging source.\u003cbr\u003e2) Ensure no load on the secondary battery bank exceeds the rating of the relay when on.\u003cbr\u003eIn the event of having a large load such as a 2000W + inverter, anchor winch or bow thruster then please look at our range of Current Limiting Voltage sensitive relays to deal with these high loads. \u003cbr\u003eIf the relay is to be used on a battery bank with a solar cell which is required to charge other batteries when the engine\/battery charger is off then please look at the Latching Relay products, as this is more suitable for that operation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFeatures of the Analogue VSR\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eIP66 Waterproof\u003c\/td\u003e\n\u003ctd\u003eFixed voltage switching\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFixed time switching delay\u003c\/td\u003e\n\u003ctd\u003e12 or 24V unit only\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnti relay contact arching protection\u003c\/td\u003e\n\u003ctd\u003eHigh quality brass connections\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelay electrical override ability\u003c\/td\u003e\n\u003ctd\u003e1 LED active information\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBi directional operation only\u003c\/td\u003e\n\u003ctd\u003e\u003cbr\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Sterling Power Products","offers":[{"title":"24V 80A","offer_id":55986689507702,"sku":"VSRA8024","price":86.4,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/7343\/files\/IMG_6729white.jpg?v=1753376148"}],"url":"https:\/\/sterling-power.com\/collections\/vsrs.oembed?page=2","provider":"Sterling Power Products","version":"1.0","type":"link"}