Estimate battery runtime, required amp-hour capacity, or supported load from voltage, power or current, usable capacity, and system efficiency.

Required: battery voltage, capacity, and load.
The share of nameplate capacity available before recharge.
Use inverter or conversion efficiency when the load is not direct DC.

Battery Run Time Formula

The following equation is used to calculate the total run time of a battery.

T = C * V / LP
  • Where T is the time in hours
  • Where C is the capacity (ah)
  • V is voltage (volts)
  • LP is the load power (watts)

To calculate the battery run time, divide the amp hours by the power output.