If you frequently charge your mobile phone with a car charger, you may be doing more harm than good to the device’s battery. Tech blogger Chris Pirillo published an e-mail from Chris Levo of Nteract Solutions discusses how the unregulated power supply in your car can cause damage to your cell phone.

Any charger that goes into the car is bad for the device battery. Why? Because the power is not regulated like in your home. In my line of work, I have seen many batteries die because people use their car chargers WAY too much. A car charger should be a LAST resort.

According to Levo, you should never charge your phone in the car unless its an absolute necessity.