Why Car-Charging Your Phone May Be a Bad Idea

By Robert Edbrooke

Plugging in your phone is likely one of the first things you do when you get in your car. But did you know that charging your phone in your vehicle—whether with a cigarette-lighter adapter or a USB cable—could have a damaging effect on the phone's battery?



Built-in USB Ports

"The USB ports in your car seem like a convenient feature, but often don't provide enough power to charge your device while in use. You need two amps to charge a cell phone while they often only have 0.5 amps," Scott Franklin of Ventev Mobile—a mobile-phone accessories company—says.

"[USB ports] only slow the speed at which your battery drains." Think of it as running in place, he says. While Franklin notes that some carmakers are now installing higher powered USB ports that will rectify this situation, those are still rare.

Off-Brand Chargers

"Stay away from unreliable drugstore chargers," Franklin says, referring to the kind that plugs into a car's 12-volt receptacle—better known as the cigarette lighter. Although they may state that they have enough power, "Their capacity often falls short of what is advertised, and if the charger has two USB ports, it probably divides the power between both ports."

Some off-brand chargers may regulate voltage poorly, potentially damaging the phone by overheating, he warns. These problems are exacerbated by power surges like blasting the AC—particularly in older vehicles. As a result, using a charger that's not manufacturer-approved could even void your phone's warranty.

The Solution

The best approach? Don't compromise your phone with a potentially damaging charger. Top phone manufacturers sell approved accessories—including 12-volt adapters containing USB and power ports—from their websites and retail outlets. Look for an adapter that provides at least two amps from the USB port and limits surges that may affect the phone.

Don't connect your charger until the car is up and running, and disconnect the lighter adapter when you're not using it; plugged in, it draws energy from the car's battery when the vehicle is off.

If you want to avoid the issue altogether, bypass your car's charging capabilities and use a mobile battery to plug in on the go. That way, you'll save two batteries: the one on your phone and the one in your car.

This article was originally published on GEICO.

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Opinions expressed by the author are not necessarily those of WITI.