[see
Forum Thread this is taken from for more]
Charge Rate, or
C-rate, is a measure of how fast a battery is charged or discharged relative to its maximum capacity, or going from empty to full or full to empty. The
maximum C-Rate is the fastest charging time (most amps) without damaging the battery, it can be different for charge and discharge and is found on the datasheet.
An empty lead acid (LA) 12 volt battery would be down to 10.5 volts (V). Likewise, a 6V LA battery is considered empty at 5.25V. Generally, when you see a battery listed at a certain amp-hour (Ah) capacity, it is usually at a 20 hour C-rate. This means it takes 20 hours to fill or empty the battery at that rate. For example, a 225 Ah (Amp-Hours) Trojan T-105-RE battery at a C-20 rate would be 225 amp-hours ÷ 20 hours = 11.25 amps (A).
