***Even though your car may be off, some car chargers will still be on and you can determine whether it’s on or not by looking at its LED light. In the case when the car charger is still active, the car charger will drain the car battery. When the car charger is not in use, it is best that you remove it and store it away in the glove compartment of your car.
***During extremely hot conditions, your car charger will really heat up when it is charging a device. Depending on how hot the charger gets, it can melt through its own plastic shell and can start burning parts of your car. The best thing to do is to keep the inside of your car cool by either turning on the AC and keeping the charger away from direct sunlight during hot conditions.
***Another thing that people tend to do with car chargers is removing them by pulling onto the cable. The cable of the car charger is the most fragile part of the charger and can easily tear or wear out. Pulling on the cable fasten the tearing and will eventually expose the wire connectors, which can lead to possible electric shock or fire.
Hope this guide helped! Dont forget, YOU got it from a Geek!