This faithfull compact 4ah 48 watt maximum rated battery charger is designed for use with 12v lead acid batteries with a capacity of between 20 65ah an easy to read led readout system indicates the batterys state of charge making it simple to see when the battery is fully charged and ready for use also suitable for use as a battery tester the charger has many safety features including thermal overload protection short circuit protection over current protection double insulation ce approval spe