I know it’s a typo, but you keep continuing confusing the guy. A fest on bulb it’s 10W nor 10A. Even a headlight bulb of 55w does not draw 10A, only a 4,5A.It would be 1A (well slightly less). Not 1A per hour, which doesn't make sense (that unit would actually represent the acceleration of current usage, which is irrelevant to this situation). If you ran a 1A device for one hour, it would use 1Ah. A 12V 10A festoon bulb would use approximately 21Ah, assuming all the wattages and voltages were the same as their rated values).