Why Charging Your Phone in Your Car Might Not Be As Helpful As You Think

Updated: Jul. 17, 2023

Odds are, you do it every day!

car phone chargerCasezy idea/Shutterstock

While you’re stuck in traffic, it may seem like the perfect time to charge your phone with the car’s USB port. But unless you’re desperate, charging your iPhone during your commute might be a big mistake.

Your Car’s USB Port

Why? For starters, the USB port in your vehicle probably provides less electricity than your phone really needs to charge. As a result, your phone might stall while it charges, or barely charge at all.

“Many people may notice that on their drive home from work their phone charged very little (if at all) during their 30 to 60 minute commute,” Brad Nichols, a technician at Staymobile, told Reader’s Digest. “This is mostly due to the fact that the phone is using more power than the car charger is supplying it.”

Too Much Power

Nichols also says that your phone could receive too much power, especially if you’re using a “cigarette lighter” port to charge up. Newer car models don’t typically come with cigarette lighters anymore, but most cars still have one or two of the same 12V sockets that used to power cigarette lighters. Most 12V sockets can supply up to ten amps, while most chargers use one to three amps. Learn how to fix cigarette burns in a car.

A malfunctioning or damaged charger can provide inconsistent power to the device, resulting in sudden spikes or surges that could cause overheating, damage to the internal components, or on the rare occasion, destroy the device.

Your Car’s Battery

Charging your phone while on the road could drain your car’s battery, too. If you leave your car running on “accessory” — where your engine is off, but you still use the radio — the device will draw power from your car’s battery as it charges.

This usually isn’t a big deal for those who own new cars with healthy batteries, Nichols says. But if your car is an older model, you might want to avoid charging your phone through its USB port.

Safety First

Most importantly, it’s not safe to use your phone while operating a vehicle. “Anytime a person’s hands leave the wheel or eyes leave the road, it becomes incredibly dangerous for them and the other people around them,” Nichols says.

Bottom line: play it safe, and wait until you get home to plug in your phone.