Ignition Feed Relay Pro Con IF

Pro connect ignition / signal feed relay

Ignition feed/D+/signal feed relay:
This range of low cost low signal activated relays is the simplest in the range, it offers the ability to link together as many battery banks as you wish and therefore charge different battery banks on a boat / vehicle when the engine is running.
Ideal applications: Boats with outboard motors and simple cabin batteries with no heavy loads on the cabin batteries, small vehicles / boats with auxiliary battery systems with low loads on the auxiliary battery bank which are not in excess of the rating of the relay so as not to overload the relay circuit.
Its limitations: There is no current limit with this type of device, so avoid using it on a system which have a high secondary battery load, such as a big inverter, anchor winch or bow thruster, as the surge currents associated with this type of equipment can destroy the unit (see current limiting relays for this application).
Starter battery interlock: this unit has the ability to interlock with up to 2 engines starter motors to ensure the relay is inactive when starter motors are engaged, thus protecting the relay and avoiding fuses blowing.
Start up time delays: A 30 second start up time delay prevents the relay coming on while the engine is being started, again protecting the relay circuit and preventing fuses blowing and damage to the relay.
Advantage over a standard relay:  A standard relay has an activation feed via a cable. This feed takes about 0.5A to run, which adds the 0.5A to where you are taking the feed from, either the D+ on the alternator or key switch or oil pressure switch. This can place enough extra load on these circuits to cause a problem. There is also the secondary problem of voltage drop in the ignition feed cable affecting the relay. The Sterling IF product overcomes this by only using the ignition feed as a signal and takes no power from the ignition feed wire. The signal then activates an internal control system, which in turn activates the relay from main power circuit internally. This also has the advantage of not suffering from voltage drops in the feed line and allows the relay to run cooler. This unit is also waterproof and in a much safer package form. The package also contains anti-spark protection to help reduce the effect of back EMF from open circuiting the relay under heavy loads, without this relays will weld close if the unit is switched off under high current pass applications. The connection terminals are also high quality brass nuts and bolts gold plated and not poor quality crimp connectors which are not suitable for high sustained current flow.