Using this car accessory socket adaptor is easy. Simply plug it into your car's lighter socket. You can then connect your mobile phone charger, kids' game console, portable GPS, or other suitable devices to the available sockets. Remember, the three smaller sockets are rated at 2 amps, so don't use high - power devices on them. The lighter socket can handle up to 10 amps. As for the battery check indicator, just glance at it occasionally to see the battery status. When it comes to maintenance, keep the adaptor clean and dry. If you're not using it for a long time, unplug it from the car to avoid any potential power drain. And always check the 10 - amp fuse regularly. If it blows, replace it with a new one of the same rating to keep your device and vehicle safe.