Reserve Capacity

The "Reserve Capacity" is an estimate of how long the vehicle can be driven with no generator output, the headlamps turned on, and minimum electrical load (most accessories turned off). It is the maximum amount of time (in minutes) it will take for a fully charged battery, being discharged at a constant temperature of 27°C (80°F), to reach a terminal voltage of 10.5 volts. (Other temperatures or current draws, the state of charge, the condition of the battery, etc., will all affect how long the battery will actually last when the vehicle is being driven and there is no generator output to the battery).