Operation CHARM: Car repair manuals for everyone.

Ratings

A battery has two ratings: (1) a reserve capacity rating designated at 27 °C (80 °F), which is the time a fully charged battery will provide 25 amperes current flow at or above 10.5 volts; and (2) a cold cranking amp rating determined under testing at -18 °C (0 °F), which indicates the cranking load capacity.