Solar battery lifespan: cycles, ageing and warranties
Sources checked
Cycle count and warranty length do not determine battery life on their own. Batteries age with time and use. Compare the test temperature, depth of discharge and remaining-capacity criterion behind any published cycle figure.
Read the conditions behind the number
A cycle claim may apply only under particular charging rates and operating conditions. Dividing a quoted cycle count by 365 does not turn it into guaranteed service years. Calendar ageing continues even when the battery is not heavily cycled.
The stated remaining capacity at the end of a test is a performance criterion, not a prediction that the device suddenly fails on that date.
Read the whole warranty
A warranty can simultaneously limit years, total energy throughput and permitted operating conditions. Check registration, connectivity, installation, firmware and temperature requirements for the exact model and region. Establish who handles a claim and whether labour or transport is included.
Budget replacement as a scenario. Today's module price does not establish the price or availability of a compatible replacement years later, and a battery warranty does not automatically renew the entire installation.