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Battery Runtime and Duty Cycle

Estimate runtime from nominal charge, current or power and awake/sleep duty cycles.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

The worked inputs demonstrate the selected model; change a known value or leave an editable unknown empty for a supported inverse.

runtime=capacity×(1−reserve)/mean current

Worked example

Enter these known values and leave the other values blank.

Battery capacity
1000 mAh
Device current draw
100 mA
Discharge safety
20 %
Battery life
8 hrs

Assumptions and limitations

  • Capacity and voltage are nominal constants. The estimate excludes aging, temperature, rate-dependent capacity, converter loss and self-discharge.
  • Reserve is at least zero and below 100 percent. Awake/sleep averaging uses their time durations as weights.

Common questions

What does this model assume?

Capacity and voltage are nominal constants. The estimate excludes aging, temperature, rate-dependent capacity, converter loss and self-discharge. Reserve is at least zero and below 100 percent. Awake/sleep averaging uses their time durations as weights.

How do units and inverse calculations work?

Choose compatible units for each quantity. The model converts quantities internally; supported editable fields can be solved from sufficient independent known values. Display rounding does not change the underlying value.

References

Explicit model domains enforce physical bounds and strict whole-count membership where required. Explanatory image content is replaced by original dimension descriptions without changing its visibility.

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