i,ve a mate thats an auto electricion the chargers that come with the tiga lamps only put out a small charge and can take a long long time to charge i,ve no idea of the technical data but you,re far better with a car battery charger remebering it,s only 6v of course and never ever store them flat and never leave them on there side the acid can erode the terminals inside you can get a good 12ah 6v battery of the tinternet for about £12