Lithium Iron Phosphate (LiFePO4)

Lithium iron phosphate (LiFePO4 or LFP) is a lithium-ion battery chemistry that has become the dominant choice for solar energy storage, off-grid systems, and RV/marine house banks. The chemistry uses an iron phosphate cathode, which provides exceptional thermal stability, long cycle life, and inherent safety advantages over other lithium-ion formulations.

LiFePO4 batteries typically deliver 2,500 to 5,000+ charge-discharge cycles at 80% depth of discharge — roughly 5 to 10 times the cycle life of lead-acid batteries. Their flat discharge curve maintains a steady voltage throughout most of the discharge range, providing consistent power delivery to connected equipment.

Safety is a major differentiator. The iron phosphate chemistry is thermally stable and does not undergo thermal runaway (the uncontrollable overheating and fire risk associated with some lithium-ion chemistries like NMC or NCA). This makes LiFePO4 ideal for indoor installations, enclosed compartments, and applications where safety is paramount.

LiFePO4 batteries weigh roughly half as much as lead-acid batteries of equivalent capacity and can be discharged to 80-100% of their rated capacity versus only 50% for lead-acid. This means a 100Ah LiFePO4 battery delivers 80-100Ah of usable energy compared to only 50Ah from a 100Ah lead-acid battery.

The upfront cost premium over lead-acid is offset by dramatically longer lifespan and deeper usable capacity. On a cost-per-cycle basis, LiFePO4 is significantly cheaper than lead-acid over the system's lifetime.