Enter the total battery capacity in amp hours and the energy usage in watts to calculate the total battery run time.

Battery Run Time Formula

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

T = 10 * a / w

  • Where T is the time in hours
  • a is the amp hours (battery capacity)
  • w is the power output/usage

Battery Run Time Definition

A battery run time is the total time in hours that a battery can sustain a certain power output.

Battery Run Time Example

The following is an example of how to calculate a total battery run time.

  1. First, determine the battery capacity. This is the total energy storage the battery can hold in amp-hours. For this example, we will say that value is 100 Ah.
  2. Next, determine the power output. This power output is also known as the usage rate and is measure in watts. We will say 50 watts for this problem.
  3. Finally, use the formula to calculate battery run time. 10 * 100 /50 = 20 hours.


What is battery run time?

Battery run time is the total amount of time a battery can sustain a certain power output. This run time will depend on several factors including discharge %, battery size, type of batter, and many more.