Reserve capacity is sometime used to rate deep cycle batteries. It is the number of minutes that a battery can maintain a useful voltage (over 1.75 VPC) at a constant 25 amp discharge rate at 80 degrees F. Reserve capacity is probably a more useful measure than AH for batteries that run heavy loads, although most batteries also have tables that show the AH capacity at different discharge rates. AH is approximately equal to RC X .60 (from the glossary on deep cycle batteries at:
Mine are 120 minutes and in series so the total is 120 minutes (same as lowest in series) If batteries in parallel, add the reserve capacity of each. http://www.windsun.com/Batteries/battery_Glos.htm
