Battery Planner

Calculate how long your batteries will last on a given rig and how many you need for a full shooting day.

Battery

Capacity input
Wh
mAh
V
%

Rig

List all devices powered by the battery. Power draw is typically in your camera/monitor specs.

Device Power (W) Count
Total: — W

Shooting Day Plan

hours
Charger (optional)
W
W
Some chargers deliver full power to a single battery but split power when multiple are connected.

Results

Runtime / battery —
Total runtime —

Batteries for the Day

Needed (no charger) —

Related Tools

How the Battery Planner Works

The Basic Formula

Runtime (h) = (Capacity × Usable% × Efficiency) ÷ Total load (W)

An internal 90% efficiency factor accounts for DC-DC converter losses and heat — real-world runtimes are always slightly shorter than the theoretical maximum. The usable capacity default of 80% protects battery health by avoiding deep discharges.

Wh vs mAh

Watt-hours (Wh) directly measure usable energy. If your battery is rated in mAh, multiply by nominal voltage: Wh = (mAh ÷ 1000) × V. Example: a 14.4V, 6600 mAh V-Mount = 14.4 × 6.6 = 95 Wh.

Shooting Day Planning

Batteries needed = ⌈ shooting hours ÷ runtime per battery ⌉. Round up — you always want a spare.

Charger Strategy

If you can't bring enough batteries, a charger running in parallel reduces how many you need to carry. The key number is how many batteries the charger can cycle during your shooting day: charged batteries = shooting hours ÷ charge time per battery. Bring fewer batteries from the start, rotate them through the charger while the others are in use.

Note: some dual-slot or quad-slot chargers deliver less power per slot when multiple batteries are charging simultaneously — enter the per-slot wattage in the multi-battery field to get an accurate estimate.