BATTERY BACKUP
UPS runtime estimator
Estimate outage runtime from battery specifications and actual network load, while checking both W and VA ratings.
2. Estimate
Estimated runtime—
Hours—
Estimated usable energy—
Recommended minimum—
W rating check
VA rating check
Important: This is a simple energy model. Lead-acid batteries deliver less than rated Ah at high loads; temperature, age and UPS cutoff voltage also matter. Prefer the manufacturer runtime curve for a specific model.
Formula
Nominal Wh = V × Ah × battery count
Usable Wh = nominal Wh × inverter efficiency × usable battery factor
Estimated hours = usable Wh ÷ load W