Engadget Explains Why Phones Overheat on CarPlay and Android Auto

Engadget said CarPlay and Android Auto remain useful in compatible vehicles, including rentals, because they put high-performing apps on a screen larger than a 6-inch phone and avoid relying on built-in car apps that are often slow or poorly designed. But both platforms can suffer cutouts at specific locations linked to electromagnetic interference, and CarPlay navigation can run substantially smoother on 5G than 4G even with a relatively recent iPhone. The likely reason, according to Engadget, is that apps such as Apple Maps process data constantly while driving. Overheating can make those problems worse, because the phone may throttle performance, halt charging or shut down to prevent crashes or damage.

The article attributed the risk not only to environmental conditions but also to power and software demands. In some situations, weather and placement are the main factors. A phone exposed to bright sun for hours will absorb heat, and Engadget said a windshield mount is probably a bad idea when driving through the Texas Hill Country in July. A vent mount can be problematic during a frigid Chicago winter if the heater is turned up full-blast.

More often, Engadget said, the causes combine. A phone sitting on a wireless charger generates more waste heat than charging via USB, a phenomenon drivers can test at home with a Qi or MagSafe charger by touching the back of the phone after it has been attached for a while. Even wired charging will raise temperatures somewhat if it is nonstop. At the same time, the phone is usually handling several tasks at once. Navigation is the most demanding, Engadget said, because an app such as Apple or Google Maps not only transfers data over 4G or 5G but also renders 3D terrain while matching it against GPS location. Music or podcasts may be playing simultaneously, along with normal background tasks. The only practical ways to push a phone harder, according to the report, are 4K video editing and console-quality 3D gaming.

Wireless versions of CarPlay and Android Auto invoke the phone's Bluetooth, Wi-Fi and cellular radios at the same time. Bluetooth establishes the initial handshake, cellular connects to the internet, and Wi-Fi links apps to the car's dashboard. Engadget said this burns a lot of juice, as a driver may notice after an hour around town without charging, and that attempting an intercity trip without plugging in is arguably reckless.

For heat control, Engadget recommended avoiding charging mid-drive on shorter trips, including around town or to the outskirts, unless the phone is already low on power or there will be no opportunity to plug in again for a long time. If charging is necessary, USB should be chosen over wireless when possible. Heat from Qi or MagSafe is not inherently problematic, the report said, but switching to USB may be enough to rein things in. Drivers should also pay attention to air conditioning and heating levels and where the phone rests. A console tray or passenger seat can cause trouble depending on how the sun hits it. If the AC is running, a mount or aimed vents can take advantage of the cooler air.

Engadget said there is usually not much drivers can do to keep phone software under control, though they might switch to 2D-only maps if available or hold off from using audio apps when radio, conversation or silence is acceptable. The report also suggested rebooting the phone periodically when back on foot, which clears system caches and restarts system processes to improve performance efficiency. If those steps and cabin temperature are managed, Engadget said, there is no reason for a phone to run hot during every ride.