Kerry, do you mean 650 Amp-hour? Give me either the watt rating or the resistane of the light bulb, and I can calculate that for you. D^2, not exactly a EE, but that's not too challenging Quoting Kerry Pinkerton <pinkertonk@xxxxxxxxx>: > Can one of you EEs tell me how long with a fully charged 650amp battery > light two tail light bulbs single filament, 12 V. > > Thanks > > Kerry > wheelingmachines.com > dte.net/57imperial >