Charging a house bank while driving without cooking the alternator.
Why alternators need a DC-DC charger
A lithium bank pulls more current than the alternator was designed for; a DC-DC charger caps it and applies the right profile.
- What Is Victron Orion-Tr Smart DC-DC Charger
- Can You Charge a 12 Volt Lithium Battery with a Car Alternator
- Can a Normal Alternator Charge a Lithium Battery
- How To Charge Lifepo Battery With Alternator
Sizing and installation
Size the DC-DC unit to the alternator’s spare capacity, then cable and fuse it like any other high-current feed.
- How Do Temperature Ranges Affect Charging and Discharging
- What is the Lowest Temperature to Charge a LiFePO4 Battery
Charging & BMS questions
Short answers to the ones that come up most.
What charger does a lithium battery need?
One with a lithium (LiFePO4) profile matching the pack voltage and BMS protocol. A lead-acid charger overcharges the pack and the BMS keeps disconnecting it.
What does a BMS protect against?
Over- and under-voltage, over-current, short circuit and temperature extremes, plus cell balancing. It cannot add capacity or repair a weak cell.
What voltage should I charge to?
3.45–3.65V per cell — about 14.2V for a 12V pack or 56.8V for a 48V pack.
Can I charge below freezing?
Not without a heater. Discharge in the cold is fine; charging below 0°C permanently damages the cells.
How do I know the charger matches the battery?
Check voltage, current limit and protocol. If the charger cannot read the BMS, it will eventually over- or under-charge the pack.
