What warranty comes with a solar battery?
Home solar batteries are typically warrantied for around 10 years, or a set number of charge cycles, with a guaranteed remaining usable capacity at the end (often around 60% to 80%). Always compare the usable capacity, the cycle or year limit, and the end-of-warranty capacity, rather than just the headline kWh figure.
What a battery warranty covers
- Term: usually around 10 years, sometimes expressed as cycles.
- Usable capacity: the kWh you can actually draw, not the nominal figure.
- Throughput: total energy guaranteed over the life, on some warranties.
- End-of-warranty capacity: the percentage retained at the end.
Comparing batteries fairly
Two batteries with the same nominal kWh can differ in usable capacity and guaranteed lifespan. Read the warranty for the conditions (such as ambient temperature and depth of discharge) that could affect cover, and choose a reputable brand your installer supports.
Frequently asked questions
- How long do solar batteries last beyond the warranty?
- Often several years more, at gradually reduced capacity. The warranty is a minimum, not the end of useful life.
- What is depth of discharge?
- The share of the battery you can safely use. A higher usable depth of discharge means more of the nominal capacity is available each cycle.
Related questions
Indicative estimates based on UK average data. Last updated 27 May 2026.