Storage
Backup Runtime
A customer asks how long the battery lasts. The honest answer depends on what is actually on the backup panel, not on the nameplate. This calculator gives you the number, and the conversation that prevents the callback.
What it asks for
- Battery nameplate capacity (kWh)
- Usable DoD (%)
- Average load during outage (kW) — Fridge + lights + internet is usually 0.6–1.5 kW.
- Round-trip + inverter efficiency (%)
- Daily solar recharge (kWh/day) — Zero if the array is offline or it is a storm. Otherwise use a cloudy-day number.