A C-rate is a measure of the rate at which a battery is discharged relative to its maximum capacity. A 1C rate indicates the discharge current will discharge the entire battery in 1 hour. For a battery with a capacity of 100 Amp-hrs, this equates to a discharge current of 100 Amps. A 5C rate for this battery would be 500 Amps, and a C/2 rate would be 50 Amps. For solar applications C10 batteries are recommended.