Typical settings at 25 °C (12 V)
| Battery | Absorption | Float | Equalise | Low-voltage cut-off |
|---|---|---|---|---|
| LiFePO4 (4 cells) | 14.2 V (13.8–14.6) | 13.5 V (13.4–13.6) | Never | 12.0 V |
| AGM | 14.4 V | 13.5 V | Usually not | 11.7 V |
| Gel | 14.1 V | 13.65 V | Never | 11.7 V |
| Flooded | 14.7 V | 13.5 V | 15.5 V occasionally | 11.7 V |
For 24 V systems double these figures; for 48 V multiply by four.
Temperature compensation
A 12 V lead-acid battery has 6 cells, so it needs about 24 mV less per °C above 25 °C and 24 mV more per °C below. Many chargers do this automatically with a battery temperature sensor. LiFePO4 batteries don't use temperature compensation, but must not be charged below freezing.
Why float matters for lithium
Keeping LiFePO4 at 100% for long periods shortens its life. A float voltage around 13.4–13.5 V lets the battery rest at a lower state of charge while the charger still supplies loads.
Frequently asked questions
What is the charging voltage for a 12V LiFePO4 battery?
Typically 14.2–14.4 V absorption and 13.4–13.5 V float, but check your battery's datasheet. Some allow up to 14.6 V.
Can I charge LiFePO4 with an AGM charger setting?
Often yes at 14.4 V absorption, but make sure equalisation and temperature compensation are switched off, and the float is no higher than about 13.6 V.