LiFePO4 (lithium iron phosphate) has become the default chemistry for deep-cycle applications — solar storage, backup power, off-grid and telecom. This guide compares it to lead-acid on the factors B2B buyers actually weigh, so you can specify the right chemistry with confidence.
Cycle life
LiFePO4 typically delivers 4,000–6,000+ cycles, versus a few hundred for a typical lead-acid battery. Across a 10-year project that often means one LiFePO4 bank instead of several lead-acid replacements.
Usable capacity (depth of discharge)
LiFePO4 can be discharged deeply — 80–100% DoD — without damage. Lead-acid is usually limited to ~50% DoD to preserve life, so a 100 Ah lead-acid battery may only deliver ~50 Ah usable. In practice you need roughly twice the rated lead-acid capacity to match the same usable energy.
Weight and size
For the same usable energy, LiFePO4 is roughly one-third the weight and a smaller footprint — which matters for transport cost, mounting and portable designs.
Charging and efficiency
LiFePO4 charges faster, accepts higher current, and has ~95–99% round-trip efficiency versus ~80–85% for lead-acid — less energy wasted as heat each cycle.
Total cost of ownership
A higher upfront price is offset by far more cycles, more usable energy per cycle and higher efficiency. On a cost-per-usable-kWh-over-life basis, LiFePO4 is almost always cheaper for cycling applications, even though the sticker price is higher.
When lead-acid still makes sense
Very low-cycle or standby uses, extreme short-horizon cost sensitivity, or where existing lead-acid infrastructure must be reused.
Building a LiFePO4 pack
For deep-cycle storage the 32700 and 32750 LiFePO4 cells are the most common choices; larger systems may use the 4680. All are available with UN38.3 test summaries and cell-safety certificates.