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Battery Life

Runtime = capacity ÷ load. Real packs deliver less than the label under high current, cold, or near end of life — the derate factor accounts for that.

Capacity (mAh)

Average load (mA)

Nominal voltage (V)

Usable fraction

Runtime

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Energy

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Runtime (days)

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Use the average current over a duty cycle, not the peak — sleep current usually dominates a battery-powered design.

A helper, not a substitute for engineering judgment. Verify against the governing standard.