Reserve Capacity (RC)
RC is a general indicator of how long a new, fully charged battery can continue to operate essential accessories if the vehicle’s alternator fails. It identifies how many minutes the battery can deliver a constant current of 25 amps at 80°F without falling below the minimum voltage, 1.75 volts per cell, needed to keep your vehicle running.
Amp Hour and C20 Battery Capacity
Amp Hour or C20 is an indicator of how much energy is stored in a battery. It is the energy a battery can deliver continuously for 20 hours at 80°F without falling below 10.5 volts.