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Electrical

Battery Runtime Calculator

Estimate load runtime from usable stored energy and load power.

Ideal component relationshipsUnits and assumptions explained below

Circuit parameters

Runs on your device

CIRCUIT RESULT

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter nominal stored energy, load power, usable fraction.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Runtime = stored energy × usable fraction/100/load power.

A WORKED EXAMPLE

Using nominal stored energy = 500 Wh, load power = 50 W, usable fraction = 80 %, the result is 8 hours. Change these example inputs to match your task; use the method above to check each step.

What to keep in mind

Constant load. Battery age, temperature and protection cutoffs are not modeled. Ideal-component calculation for study and estimation. It does not select safe wiring, protective devices or component ratings for an installation.

Common questions

Which inputs does this calculation need?

Estimate load runtime from usable stored energy and load power. Enter nominal stored energy in Wh, load power in W, usable fraction in %. The filled example is editable and is not a saved personal record.

How should I interpret the result?

Constant load. Battery age, temperature and protection cutoffs are not modeled. Ideal-component calculation for study and estimation. It does not select safe wiring, protective devices or component ratings for an installation.

Methodology maintained by ClarityKit. How these tools are built and checked.