FREE · CALCULATORS & CONVERTERS
Battery Runtime Calculator.
Estimate usable watt-hours and runtime from amp-hours, voltage, depth of discharge, efficiency and load.
Runtime is usable watt-hours divided by the load. Temperature, the Peukert effect and a management system are not modelled. Local arithmetic only. This is a quantity or geometry estimate, not a code check and not a substitute for a licensed professional.
- Stored energy
- 1,200 Wh
- Usable energy
- 864 Wh
- Runtime
- 6 h
Usable energy = amp-hours × volts × depth of discharge × efficiency. Runtime divides that energy by the load in watts. It does not model temperature, Peukert effect or a battery-management limit.
How to use Battery Runtime Calculator
Enter the battery, the share you can use, the efficiency and the load in watts.
How it works
Estimate usable watt-hours and runtime from amp-hours, voltage, depth of discharge, efficiency and load. Runtime is usable watt-hours divided by the load. Temperature, the Peukert effect and a management system are not modelled. Local arithmetic only. This is a quantity or geometry estimate, not a code check and not a substitute for a licensed professional.
Example
A 100 Ah 12 V battery at 80% discharge and 90% efficiency, with a 144 W load.
Questions about Battery Runtime Calculator
Is Battery Runtime Calculator free, and do I need an account?
Yes. This tool is free to use in your browser without an account. Processing takes place on your device.
What are the limits and what should I check?
Runtime is usable watt-hours divided by the load. Temperature, the Peukert effect and a management system are not modelled. Local arithmetic only. This is a quantity or geometry estimate, not a code check and not a substitute for a licensed professional. Review the result before using it in your work.
Is my input sent to a server?
Your input is processed in your browser and is not uploaded by this tool. Files and pasted text are cleared when the page is refreshed. Normal website requests are still required to load the page and its libraries. Read the privacy explanation.