Battery Cycle Life explained
Battery cycle life tells you how many times a battery can be fully charged and discharged before it degrades to a specified capacity threshold — typically 80% of its original rated capacity. It's the primary measure of how long a battery will last.
For a home solar battery that cycles once per day (charge during the day, discharge in the evening):
- 3,000 cycles = approximately 8.2 years of daily use
- 4,000 cycles = approximately 11 years
- 6,000 cycles = approximately 16 years
- 10,000+ cycles = approximately 27+ years (some LFP batteries)
Manufacturer cycle life claims (at specified DoD):
- Tesla Powerwall 3: unlimited cycles within 10-year warranty period
- GivEnergy 9.5 kWh: 6,000 cycles at 80% DoD
- BYD HVM: 6,000 cycles at 80% DoD
Real-world cycle life depends on: operating temperature (heat accelerates degradation), depth of discharge (shallower cycles extend life), and charging rate (faster charging generates more heat).
Many batteries come with 10-year warranties guaranteeing a minimum 70–80% capacity retention — use this as the practical planning horizon for financial modelling, and budget for potential replacement thereafter.