What do cycle life and cell warranty mean?

Cycle life tells you how many full charge–discharge cycles a cell can withstand while maintaining its guaranteed capacity retention. Industrial LFP (lithium iron phosphate) cells typically guarantee 6,000–8,000 cycles at 70–80% capacity retention; at one cycle per day, this means 16–22 years. The cell warranty usually runs for 10–15 years and covers both the cycle count and the capacity retention at the same time — whichever is exhausted first ends the warranty. There are two pitfalls when comparing offers. The first: the cycle count always belongs to a specific set of conditions (SOC window, C-rate, cell temperature), and if the operating profile falls outside them, the warranty does not apply. The second: capacity retention means that at the end of the warranty the storage system can deliver 70–80% of its nominal capacity — not that it operates at 100% all the way until then. The financial model must therefore work with a capacity that declines with degradation. Anyone who projects the first-year performance over the entire term significantly overestimates the result.