Connect G-Charger to a vehicle battery to power your mobile device through the included USB adapter.  Alternately unplug the USB adapter and plug in any 12 volt or cigarette lighter powered accessory.  See instructions for details. 

With the vehicle running, a connected G-Charger power supply is only limited to the vehicle's fuel supply.  If the vehicle is not running then the supply of power is dictated by the life of the battery and its Amp Hour rating.  Divide the Amp Hours of the battery by the amps used by the device to get the number of hours that the battery could power the device before totally draining the battery..  In the case of the G-Charger USB adapter the maximum is 5 amps.  For example, a fully charged 100 AH battery could power devices plugged into the G-Charger USB adapter for 20 hours before the battery is fully drained,

Caution! A fully or partially drained battery will not provide enough power to start the vehicle..  Don't deplete the battery and become stranded with a vehicle that won't start!