Lithium (LiFePO4) vs AGM RV Battery
Both drop into the same battery tray, but they behave very differently. Lithium costs more upfront and gives far more usable power per pound.
| Lithium (LiFePO4) | AGM | |
|---|---|---|
| Usable capacity | Most of the rated amp-hours | About half, to avoid shortening life |
| Weight | Much lighter | Heavy |
| Cycle life | Thousands of cycles | Hundreds of cycles |
| Voltage under load | Stays steady | Sags as it discharges |
| Charging | Needs lithium-compatible charger settings | Works with most RV converters |
| Cold weather | Cannot charge below freezing without heating | Charges in the cold |
| Upfront cost | High | Lower |
Choose Lithium (LiFePO4) if
- You boondock or use lots of 12V power
- Weight matters
- You keep the RV for years
Choose AGM if
- You mostly stay at campgrounds with hookups
- You camp below freezing without battery heating
- Upfront budget is tight
The bottom line
Lithium is the better long-term battery for off-grid use because you get double the usable capacity at a fraction of the weight. AGM still makes sense for occasional campers on hookups.