Quality batteries are built for long-term use, but the exact warranty position depends on the product and manufacturer.
Warranty and lifespan:
- Manufacturer warranty — warranties vary by brand and product, and depend on the manufacturer's current terms and support arrangements. Tesla's Powerwall 3 warranty, for example, is 10 years, provided the unit stays reliably connected to the internet
- JME workmanship warranty — this covers defects caused by our installation work for six years from completion, and is separate from the manufacturer's equipment warranty
- Expected lifespan — Home Energy Scotland says batteries tend to last between 10 and 15 years, depending on how they are used
- Capacity retention — lithium-ion batteries gradually lose a small amount of capacity over time
What affects battery lifespan:
- Cycle count — each charge and discharge is one cycle
- Depth of discharge — regularly draining the battery to 0% wears it faster than shallower cycling. Modern battery management systems help manage this automatically
- Temperature — each manufacturer sets an operating temperature range (for Tesla Powerwall 3, −20°C to 50°C), and the installation location is chosen with it in mind
After the warranty period:
A battery does not automatically stop working when a warranty expires. It may continue operating with reduced capacity, subject to the condition of the unit and the manufacturer's software and support arrangements.
