Storage battery (accumulator battery). Purpose, device and types

10.2.3.c Reserve capacity

Reserve capacity (designated as Cr) is the discharge time in minutes of a fully charged battery with a current of 25 A to a voltage of 10.5 V at an electrolyte temperature of 25 °C.

Note
Reserve capacity is 1.63 times greater than the available capacity in numerical terms (for example, for a battery pack with a capacity of 55 A · h it is approximately 90 minutes). This is the time during which a fully charged battery can provide electricity to the minimum number of consumers that are required for safe driving in case of a generator failure.