Battery Backup Runtime Calculator
Battery Backup Runtime Calculator
Estimate steady AC backup hours from battery energy and an entered load.
Battery energy and the AC load together set a rough steady backup duration. Nominal capacity alone does not tell you the usable hours.
Enter discharge, health and efficiency assumptions alongside the load. Compare the result with observed runtime as the battery and operating conditions change.
How to use Battery Backup Runtime Calculator
- Enter bank nominal voltage, bank capacity and usable depth of discharge.
- Enter inverter efficiency, steady AC load and inverter DC idle draw.
- Select Calculate result. Read the returned values alongside the assumptions below before copying, exporting or acting on the result.
Why choose this tool?
The energy reductions stay visible, helping explain why nominal watt hours are greater than usable AC output.
Before you use the result
Constant power estimate. Battery age, temperature, discharge rate, BMS cutoffs and inverter idle behaviour can change actual runtime. DoD is an input, not a chemistry recommendation.
Questions about Battery Backup Runtime Calculator
Is the duration a guarantee?
No. Temperature, discharge rate, battery age, cutoffs and inverter behaviour can change actual runtime.
What should I check before using Battery Backup Runtime Calculator?
Check Bank nominal voltage, Bank capacity, Usable depth of discharge and Inverter efficiency. Use the exact units shown beside the controls and replace any example values with your own inputs.
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