Tool

Amp Hour Calculator 12V

Estimate required battery amp-hour capacity based on load, runtime, and voltage.

Amp Hour Calculator Ah = (Watts x Hours) / (Voltage x Efficiency)

Load Power

Total power draw of connected load

Runtime

How long the load must run

Battery Voltage

Nominal battery voltage

System Efficiency

Use 0.85 to 0.95 for inverter/battery losses

Use lower efficiency values for conservative sizing in real systems.