Battery Life Calculator
A simple runtime is capacity ÷ load. For mAh and milliamps: hours = (mAh ÷ mA) × efficiency. Real batteries sag, and Peukert’s law shortens runtime at high current — treat this as an upper bound.
Estimated runtime12.75 hours
Estimate only.
Formula
Hours ≈ (capacity ÷ load) × efficiency.
How to use this calculator
- Choose mAh or Wh.
- Enter capacity and matching load.
- Derate with efficiency (80–90% is typical).
Examples
3000 mAh at 200 mA, 85%
About 12.8 hours.
FAQ
Why not 15 hours?+
Conversion losses, cutoff voltage, and temperature reduce the ideal mAh ÷ mA figure.
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