Battery Power Calculator

Calculate battery capacity needed for your devices over a multi-day trip. Covers phones, headlamps, GPS units, cameras, and other electronics.

Results

Visualization

How It Works

A typical phone battery is 3,500 mAh. In airplane mode, a phone lasts 2-3 days. Power banks lose 15-20% in the charging conversion. For trips over 5 days, a 10W solar panel (6-7 oz) can supplement a smaller power bank. Keep batteries warm in cold weather — lithium loses capacity below freezing. USB-rechargeable headlamps save carrying spare batteries.