Battery Life Calculator (Duty Cycle + Regulator Losses)
Estimate battery life from active/sleep currents, burst duration, cycle period, and regulator efficiency. Get average current, mAh/day, and Wh/day.
Quick start presets
Presets load example numbers to guide you—adjust them for your real measurements.
Inputs
Presets are starting points—validate with your real load profile.
Power path
Duty cycle
Estimated lifetime
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Avg battery current
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Avg load current
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mAh / day
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Wh / day
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Duty cycle
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Sleep per cycle
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Checks & notes
- Adjust inputs to see instant updates.
Practical measurement tips
Sleep current
For µA sleep, use a dedicated meter or power profiler. Don’t forget LEDs, pull-ups, sensors in standby, and regulator quiescent current.
Bursts & peaks
For radio/motor bursts, measure with a shunt + oscilloscope (or a power analyzer). DMM averages can miss short spikes.
FAQ
mAh vs Wh: what’s the difference?
mAh measures charge, Wh measures energy. Voltage matters: Wh = (mAh/1000) × V. Use Wh when comparing batteries across voltages or when a regulator is involved.
Why is real life lower than the estimate?
Temperature, cutoff voltage, higher-than-expected average current, and regulator quiescent current are typical causes. Battery capacity is also specified under particular discharge conditions.
Coin cell brownouts during TX — why?
Coin cells can have high internal resistance, so a burst causes voltage droop (ΔV = Ipeak × Rint). Validate under low battery and cold conditions.