Enter the total batter reserve capacity into the calculator to determine the total amp hours left in the battery. This calculator can also perform the reverse operation.

## Battery Reserve Capacity to Amp Hours Formula

The following formula is used to convert a battery reserve capacity to amp hours.

AH = BR *60 *25 / 3,600

- Where Ah is the amp hours
- BR is the battery reserve capacity (minutes)

To calculate amp hours from battery reserve capacity, multiply the capacity in minutes by .41666.

## Battery Reserve Capacity Definition

**What is a battery reserve capacity? **

The battery reserve capacity is a measure of the total amount of time a battery can run at 25 amps of current without the voltage dropping below a set value of 10.5 volts.

## Example Problem

**How to calculate amp hours from battery reserve capacity? **

The following example problem illustrates the steps and required information needed to calculate amp hours from reserve capacity.

First, determine the reserve capacity. As mentioned above, this is a unit of time the battery can run at 25 amps without dropping below 10.5 volts. For this example problem, the battery has a reserve of 45 minutes of capacity.

Next, multiply the time in minutes by 60 to get the result in seconds:

45* 60 = 2700 seconds

Next, multiply the seconds by the 25 amps above:

2700 * 25 = 67,500

Finally, divide the result above by 3,600 to get the number of amp-hours:

67,500 / 3,600 = 18.75 amp hours