Understanding your cycle count conversion
Why cycle count alone doesn't tell you much
A cycle rating by itself doesn't answer the question most people actually want answered, which is how many years a battery will last. The same 6,000-cycle rating means about 16.5 years for a daily-cycling solar system, but well over a century for a battery only cycled occasionally for backup, so usage frequency matters just as much as the rating itself. If you want that same answer built out into a fuller year-by-year picture rather than a single number, the battery lifespan estimator picks up from here.
What counts as a full cycle
Manufacturers count cycles as total energy throughput, not literal full discharges. Two 50% discharges and recharges add up to one full cycle toward the rated total, which is one reason batteries used for shallow, frequent cycling often outlast the simple math suggests, a throughput-based counting method NREL's energy storage research uses in its own cycle life testing across chemistries. The capacity over time calculator factors in that same depth-of-discharge effect alongside calendar aging.
Why this is a starting estimate, not a guarantee
This conversion assumes a steady cycling pattern every week of the year and doesn't account for calendar aging, temperature swings, or gradual capacity fade, all of which affect real-world results. Treat the output as a planning baseline, and cross-check it against the LFP vs NMC cycle life comparison if you're still deciding between chemistries. The same gap between a rated figure and real-world results shows up in the EV battery degradation vs home battery comparison, where usage pattern also ends up mattering as much as the manufacturer's spec sheet.
What to check next
Once you know roughly how many years your battery should last, the warranty cycle count comparison checks that figure against what different manufacturers actually guarantee, the same real-versus-rated question the DOE's Office of Electricity weighs when it evaluates storage system performance data against nameplate specifications.