The minimum capacity that a lead-acid battery should be able to discharge under the conditions specified in the design, such as temperature, discharge rate, termination voltage, etc., expressed in ampere hours and denoted by the symbol C. The capacity is greatly affected by the discharge rate, so the discharge rate is often indicated by Arabic numerals in the lower right corner of the letter C, such as C20=50, indicating that the capacity discharged to the termination voltage at a rate of 20 hours is 50 ampere hours. Simply put, a battery with a rated capacity of 50 ampere hours can discharge for 50 hours with a current of 1 ampere when fully charged.