a 10-amp charger puts twice as much charge into the battery as a 5-amp one. A quick stroll through a listing of battery chargers can be confounding though. Some have 40 amps and some have 0.75 ...

The Schumacher Electric heavy-duty battery charger and maintainer ... if your car has a 50 amp-hour battery, you should look for a maintainer that can deliver at least 5 amps.