Overmax X-Rally 2.0 Manuel De L'utilisateur page 15

HOW TO CHARGE CAR BATTERY
1. Connect the charger to a USB port on your computer or to a USB power
EN
adapter. Then connect the battery to the charger. During charging the LED
lights up. When the battery is charged, the LED will turn off.
2. Unscrew the camping screw from the car battery cover and remove it.
3. Connect the battery, close the cover and screw it back on.