 For example, for a battery with "C =" 40 Ah, a current C/(10 h) (usually written as C/10, omitting the 'hours' as time unit) is equal to 4 A.The charging current is a compromise between charging time (favoring high currents), the prevention of damage due to overheating or gassing (favoring low currents), and cost of the charger (favoring low currents).Recommendations for the maximum charging current vary between C/10 and C/2.