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LiFePO4 versus lead-acid for deep cycle work
The comparison is not about capacity on the label, it is about usable capacity, cycle life and how each chemistry behaves at the end of a discharge.
A 100 Ah lead-acid battery is not a 100 Ah battery in deep cycle service. Discharging it below about half its rating shortens its life sharply, so the usable figure is closer to 50 Ah. A 100 Ah LiFePO4 pack can be taken far deeper without the same penalty, which is why the two are not comparable on label capacity.
Voltage behaviour differs as much as capacity. Lead-acid sags progressively through a discharge, so a device sees falling voltage as the battery empties. LiFePO4 holds voltage much flatter and then drops at the end, which is better for the load and worse for anyone judging state of charge by voltage alone. That is one reason a smart BMS matters.
Cycle life is where the economics land. Our 51.2V storage packs are rated above 6000 cycles; a deep-cycle lead-acid bank in the same service is typically an order of magnitude below that. The upfront price comparison and the cost-per-cycle comparison point in opposite directions.
Specifications
| Usable capacity | Lead-acid roughly half its label in deep cycle service |
|---|---|
| Voltage behaviour | LiFePO4 flat then drops; lead-acid sags progressively |
| Cycle life | 6000+ on our 51.2V storage packs |
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Send us the application and the load
Tell us what the pack has to power, for how long, and which inverter or charger it works with. You will get a sized recommendation with capacity, dimensions, BMS rating and cycle life in writing.