I wouldn't use a car battery charger. It will be TOO much amperage for that small battery. As long as it is a rechargable, you should really use a trickle wall charger. They look like a power adapter. Mine is a Hobbico and the output is DC 12V 6W 600mA. If the battery is real low it may take a day or more to bring it fully back if it is only partially down overnight may be enough. The proble with these chargers is that you don't know when you have reached full capacity. I'm open for suggestions also on chargers that will tell you when you have a full charge. I'm going to email Hobbico, if they get back to me I will post what they tell me.