Modern lithium iron phosphate (LiFePO4) batteries are extremely durable and designed to last 15-20 years with virtually no maintenance.
Warranty periods:
- Tesla Powerwall 3 — 10-year UK warranty with 80% retained capacity (conditions apply, including registration) - Sigenergy SigenStor — terms depend on the module generation, so we give you the current UK warranty for the exact model quoted - Whatever the brand, ask for the warranty document for the exact model, not just the headline number of years
What happens after the warranty? — The battery does not stop working. After 10-15 years, it may hold around 60-70% of its original capacity — similar to how a phone battery degrades over time, but much more slowly. A 10kWh battery retaining 70% still provides 7kWh of usable storage, which is perfectly functional.
Cycle life — Most LiFePO4 batteries are rated for 6,000-10,000 charge cycles. With one full cycle per day, that is 16-27 years before reaching the rated cycle limit. In practice, most home batteries do less than one full cycle per day, extending their life further.
Maintenance — There is no regular maintenance required. The battery management system (BMS) handles charge and discharge automatically. We recommend an annual visual check and system health review as part of a maintenance plan, but there are no consumable parts to replace.
Replacement — When the battery eventually needs replacing (likely 15-20 years from now), battery technology and prices will have improved significantly. The inverter and wiring infrastructure remain in place.