Lithium costs more up front and far less over its life. Here is how to compare the two honestly and decide when a switch pays off.
Lead-acid is proven, low cost and recyclable. Lithium iron phosphate (LiFePO4) costs more to buy but delivers more usable energy, far more cycles and almost no maintenance. The right choice depends on how hard you cycle the battery and how long you keep it.
| Factor | AGM / GEL (VRLA) | LiFePO4 |
|---|---|---|
| Up-front cost | Low | 2 to 3 times higher |
| Usable capacity | ~50% of rated (deep cycle) | ~90 to 100% of rated |
| Cycle life (to 80%) | ~400 to 1200 cycles | 2000+ cycles |
| Weight | Heavy | ~50 to 60% lighter |
| Charge time | Slow, multi-stage | Fast, high charge acceptance |
| Maintenance | Low (sealed) | None; managed by BMS |
A 100 Ah lead-acid battery in deep-cycle service gives roughly 50 Ah before you should recharge. A 100 Ah LiFePO4 gives close to 90 to 100 Ah. So a lithium battery often replaces a much larger lead-acid bank, which changes the cost comparison before you even count cycle life.
If you cycle the battery most days, lithium usually wins on cost per usable kWh over its life. If it mostly sits on float, lead-acid is hard to beat on price.
This guide is provided by ATB Power for general information. Figures are typical and may vary by model; always confirm against the specific product datasheet. © 2026 ATB Power.