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Sterling Power
BB1248120 Battery to Battery charger (12V/120A 24V 60A--->48V/30A)
Correctly and quickly recharges 48V lithium batteries
Also available on our site: the 65A version.
This DC-DC draws up to 120A from the 12V alternator, recharging the 48V lithium batteries with a current of 30A.
We recommend using this DC-DC with an alternator of at least 240A at 12V or 120A at 24V.
12V/24V to 48V DC to DC Charger - BB1248120
A powerful and efficient 12V-48V DC-DC charger with 120A input at 12V and 30A output at 48V (1600W input and 1500W output).
Output power: 1500W of output power to perfectly recharge 48V batteries.
High Efficiency: the Buck Boost design delivers 93-95% efficiency for optimal performance.
Versatile charging: compatible with various types of 48V batteries, including LiFePO4 15s (BBR monitor mandatory) and 16s batteries.
Key features:
- Simple installation and configuration
- 4-stage charger
- Suitable for both 15s and 16s lithium batteries
- Recharges the engine battery at a current of ~40A (this is a bidirectional DC-DC, and this function lets it keep the 12V engine battery charged using surplus energy from the 48V house batteries)
- Jump Start Assistance Mode (being bidirectional, it can use the 48V house batteries to assist the 12V/15V engine battery during starting in emergency cases)
- Smart Alternator/Euro 6 compatible (connect D+ signal)
- Ignition feed or Vibration Sense modes
- 6 battery types
- 6 protections with automatic self-reset
Technical Specifications:
| Model | BB1248120 |
|---|---|
| Input voltage | 12V/24V |
| Output voltage | 48V |
| Input current | 120A (12V) / 60A (24V) |
| Output current | 30A |
| Input power | 1600W |
| Output power | 1500W |
Frequently Asked Questions:
Q: Can the BB1248120 recharge LiFePO4 batteries with 16 cells in series (16S) 51.2V?
A: Yes, absolutely. This unit is designed for such applications.
Q: Can the BB1248120 recharge LiFePO4 batteries with 15 cells in series (15S) 48V?
A: For 15s batteries you need a BBR (remote control) to set the correct charge voltage. You can select it among the product's purchase options. It will let you lower the charge voltage to around 53-54V, slightly reducing power.
Note: Compared to the BB124865, the BB1248120 is larger and more powerful. Otherwise, they share the same high-performance features.
Optional accessories:

Remote control BBR: external monitor for setting the charge voltage.
What does the BBR offer?
- Real-time readings of voltage and current from the BB output
- Ability to set custom charging profiles | absorption, float, and absorption time duration
- Ability to adjust the current limit to 85%, 65%, or maximum power (100%)
- Allows removing the float voltage function in lithium profiles
- Desulfation/equalization settings can be set in LEAD mode.