Most car chargers in the market are with mini USB connector or 3.5mm DC jack and the maximum voltage and ampere they could offer would be indicated on the accessories packaging.
Car charger with mini USB connectors are mostly used for mobile phone power (5V, 0.5A), but this isnˇ¦t enough to have GR-1102 work.
Please take notice of voltage and ampere marked on the packaging when purchasing the accessory to work with GR-1102.
Besides, these external power supply accessories are usually marked with ˇ§maximumˇ¨ current ampere but current ampere will decrease gradually after use. Itˇ¦s recommended to purchase branded accessories or even better with higher specification.