The chart above indicates that for 3 hours of discharge rate, the battery has only 70% capacity. Therefore, we must have 428
A
.H. of battery capacity. (Figured by dividing the A.H. capacity by the percentage of loss, or 300 A.H. ÷ 0.7 (70%)).
Therefore
we would require 428 A.H. of batteries at a stated 20
-
hour rate. If the standard 12
-
Volt battery is 105 A.H., four
batteries are
needed.