12V (only) to 48V Battery to Battery Charger w/ reverse charging feature + Jump Start Assistance

£684.00

12V (only) to 48V DC to DC Chargers 115A input and 26A output model (1600W input and 1500W output) - E-Marking | BB1248120

If you need 24V input and 48V - click here

Also, new to Q2 2024 - BB124865 - a smaller / lower powered derivative of the BB1248120. 12V and 24V input to 48V 750W battery to battery charger. Exactly the same features. Just smaller and less expensive. Pre-Orders available now.

Frequently asked questions regarding the BB1248120 | BB124865.

A common question is whether the BB1248120 is capable of charging 16 string (16S) (51.2V LiFePO4 batteries (rack style). The answer to this is absolutely yes, no issues - what the unit is made for, really.

In order to charge a 15S battery (Pylontech 48V for example) you shall require a BBR (remote) to set the charge voltage for the 15S (48.0V batteries). If the desired charge voltage is between 53.0V and 54.0V a BBR is required to change the charge voltages. There is a slight reduction in charge power, as below - depending on how low you set the charge voltage. If you set the charge voltage to 54.0V - you can get 1400W output power. 

  • The BB1248120 can be used for charging 16S Lithium batteries ~1500W (at 57.6V)
  • The BB1248120 can be used for charging 15S Lithium batteries ~1400W (at 54.0V) - BBR required
Remote control BBR - Optional remote


- Buck Boost design, offering high efficiency (93-95%)
- Simple installation and setup
- Current limiting 4 stage battery charger
- Lithium safe

-~40A reverse charge current to 13.3V

- Jumps Start Assistance Mode - watch video about it

- 12V to 48V
- BB1248120 - 1500W of output charging power

- BB124865 - 750W of output charging power

Smart Alternator/Euro 6 compatible
- Ignition feed or Vibration Sense modes
- 6 preset battery types
- 6 self recovering protections
- Low temperature trip for Lithium Ion batteries

BB1248120 Reverse Charging Feature.

The BB1248120 is able to charge in both directions. Provided there is over 52.8V on the leisure battery (54.0V if lithium) and the starter battery is below 13V the BB shall allow approximately 40A to flow back to the starter battery up to about 13.4V (float voltage). It simply allows the starter battery to remain topped up when there is surplus energy in the domestic battery. This feature will NOT drain your domestic battery - it simply takes surplus. Once your alternator / engine turns on or you provide the BB with an ignition signal the BB reverts to normal charging of the leisure battery.  This mode can be disabled, but is on as default.

This is ideal for allowing the starter battery to remain topped up when you have solar / wind / charger - charging up your leisure battery.

Generic Instructions:

 Instructions


 Battery to Battery Charger Remote Control - BBR

(Optional)

BBR comes with 4m extension cable

What does the BBR offer?
- Live voltage and current readings from BB output
- Ability to set custom charge profiles | absorption, float and absorption time length
- Ability to adjust current limit to 85%, 65% or full power (100%)
- Allows the removal of float voltage feature in lithium profiles
- Desulphation / equilisation settings can be set in LEAD modes.


Why adjust the current limit?

The default current setting for the BB range is 100% - meaning that the performance default is full power. If you wish to reduce the performance of the BB, here you can set to 85% or 65% charge rate. Examples of why you may wish to reduce performance:
1) if you have solar panels and the weather is good, by reducing the power of the BB, you shall conserve fuel.
2) The alternator is better suited running at slightly lower current than what was expected.
3) It may be recommended by your battery supplier to charge the battery up at a slightly lower current. If one of your lithium batteries within your leisure battery bank fails, you may be exceeding the C rating of the remaining batteries.
4) future proofing. If you have installed a high powered BB, in the assumption that one day you shall put a larger alternator on and/or more batteries in your system. You can reduce the power for the immediate install and increase the performance of the unit at a later date.

 Instructions


BB1248120

Input voltage range:  9V-16V
Input current rating: 115A

Output voltage range: 38-62VDC

Output current rating: 26A
Reverse current rating: 40A at 13.4V(max)
Continuous Rated output power: ~1500W
Continuous Rated input power:   ~1600W
Quiescent current:            5mA
Efficiency rating:            93-95%

Multi battery chemistries


Self recovering protections:    under voltage protection
                input over voltage protection
                output over voltage protection
                over current protection
                charge over temperature

Operational Temperature        -20 Deg C -> 60 DegC

Approval             CE | UKCA
                E-Marking 24*10R06/01*3789*00
Cooling method            Thermostatically Controlled
                Variable low speed fan

Dimensions            270mm x 130mm x 73mm
Weight                1.8Kg



BB124865

Input voltage range:  9V-32V (auto detects 12V in or 24V input)
Input current rating: ~65A at 12V and ~32A at 24V

Output voltage range: 38-62VDC

Output current rating: 13A
Reverse current rating: 20A at 13.4V(max) and 10A at 26.8V
Continuous Rated output power: ~750W
Continuous Rated input power:   ~800W
Quiescent current:            5mA
Efficiency rating:            93-95%

Multi battery chemistries


Self recovering protections:    under voltage protection
                input over voltage protection
                output over voltage protection
                over current protection
                charge over temperature

Operational Temperature        -20 Deg C -> 60 DegC

Approval             CE | UKCA
                E-Marking 24*10R06/01*3789*00
Cooling method            Thermostatically Controlled
                Variable low speed fan


Dimensions            200mm x 130mm x 56mm
Weight                1.0Kg