12V|24V to 24V 120A input | 60A output Battery to Battery Charger w/ reverse charging feature


12V|24V to 24V DC to DC Chargers 120A input and 60A output model - E-Marking | BB1224120

Auto detects either 12V or 24V input.

Remote control BBR - Optional remote

- Buck Boost design, offering high efficiency (95-98%)
- Simple installation and setup
- Current limiting 4 stage battery charger
- Lithium safe

- Jump Start Assistance Feature - please click here to read about

-~50A reverse charge current to 13.3V | ~25A reverse charge current to 26.6V

- 12V|24V input to 24V output
- BB1224120 - 1700W of output charging power - based on 59A at 28.8V

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

BB1224120 Reverse Charging Feature.

Jump start assistance feature - please click here to read about

Watch video about the Jump Start feature

The BB1224120 is able to charge in both directions. Provided there is over 26.4V on the leisure battery (27.0V 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:



 Battery to Battery Charger Remote Control - BBR


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.



Input voltage range:  9V-33V
Input current rating: 120A at 12V | 60A at 24V

Output current rating: 60A at 29V
Reverse current rating: 50A at 13.4V(max) | 25A at 26.8V
Continuous Rated output power: ~1700W
Continuous Rated input power:   ~1800W
Quiescent current:            5mA
Efficiency rating:            95-98%

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