Roadster 6-12 Volt 10 amp Smart Car Battery Charger 81499C Â Â Â Â Roadster 6 Volt & 12 Volt 10 amp Smart Car Battery Charger Barcode: 5038673814995 MPN: 81499C Roadster Battery Charger 8 Amp 6 Volt & 12 Volt Roadster Battery Charger is a versatile 8Ah / 150 Watt maximum rated battery charger, designed for use with both 6V and 12V lead acid batteries. Â The charger features a voltage selection switch that can be set to charge either 6 or 12 volt batteries, along with an ampere switch to select the desired rate of charge. Â The charger has many safety features including: Thermal overload protection.