These small but powerful converters provide a source of stabilised low voltage suitable for running many different items of equipment. Their output is ohmically isolated from the system ground and constant current limited. Continuous operation in current limit is allowed making them suitable for battery charging providing charge time is controlled. Connection to the battery is by a plug with a flying lead, that fits a standard cigar lighter socket, and output is by flying lead terminated in a popular 2.5mm concentric plug (Bare ended for 5V and 9V output units). The converters are mainly designed for use with notebook computers that have two wire input. These converters are current limited above a certain level of demand. The output isolation of the converter from system ensures that earth currents do not flow.ConnectionInput: The converter just plugs into the vehicle via its cigar lighter socket, using cable mounted plug provided. Do not leave the converter plugged in when not in use. It will still slowly discharge the vehicle battery. Output: The output connector, with centre positive, plugs into equipment if suitable. If the output connector is not appropriate, a different one may be fitted after cutting off the existing one. the output cable has a brown positive wire and blue negative wire. Battery Drain These converters draw about 1 amp from the battery for every 10 watts of actual load applied. Start your car periodically for 15 minutes to boost the battery is you use anything for a long time.What is a USB Car Charger?USB car charger is a small gadget that plugs into vehicle's cigarette lighter, and provides one or more powered USB sockets. You can choose from single USB socket or two or more sockets. It will allow you to charge more than one device at the same time.