Battery Life Calculator

Estimate how long a battery lasts.

Battery life 12.75

Formula: hours = capacity ÷ draw × efficiency

Step-by-step with your numbers:

1. Values used:

2. Battery capacity = 3,000 mAh

3. Current draw = 200 mA

4. Efficiency = 85 %

6. Battery life = 12.75

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Estimate runtime from battery capacity and current draw.

The math behind it

hours = capacity (mAh) ÷ draw (mA) × efficiency. Efficiency accounts for real-world losses.

3000 mAh ÷ 200 mA × 85% → 12.75 h.

Why efficiency?

Voltage conversion and heat waste some capacity.