LiFePO4 Battery (LFP)

LiFePO4 (lithium iron phosphate) is the battery chemistry that has become standard in quality solar street lights, displacing older lead-acid and ternary lithium designs. Its appeal is fitness for the duty: thousands of charge cycles rather than hundreds, tolerance of the daily full charge-discharge rhythm of solar lighting, stable chemistry that resists thermal runaway in a sealed fixture baking on a pole, and useful capacity retention across a wide temperature range. A solar street light cycles its battery every single night, so cycle life directly sets system life — the difference between replacing batteries every two years and every eight. When comparing solar fixtures, ask for the battery’s chemistry, rated capacity in watt-hours and cycle life at the stated depth of discharge; a vague “lithium battery” line on a datasheet hides exactly the variable that matters most.