A phone that gets too hot to hold after a car ride is a warning sign, according to a report by Engadget. Overheating can damage internal components and wear down the battery faster, the outlet said.
In the worst case, an overheated battery can suffer thermal runaway, a process in which the battery stops dissipating heat effectively and triggers an uncontrolled chemical reaction. Engadget said this is what causes the battery swelling that users often describe as a "bloated battery."
A car is considered one of the worst places for a smartphone in summer heat, the report said, because a closed metal cabin heats up quickly in the sun while the phone absorbs outside heat and generates its own from use.
Keep phones out of direct sunlight
One of the most common mistakes is leaving a device on the dashboard, according to Engadget. It is convenient for navigation, but that is where a phone heats up the most because of direct sunlight through the windshield.
The situation becomes especially risky when a phone sits in the sun while charging at the same time, the report said, since heat from the dashboard, the cabin temperature and the battery's own operation combine quickly.
Engadget recommended placing the phone in a cooler spot if it is needed for navigation, and pointing the air conditioning vent at the back of the device to help draw off heat, similar to cooling systems in laptops and computers.
Cooling an overheated phone too quickly is not advisable either, the report warned, since condensation can form inside the casing in high humidity and damage the electronics. Engadget also recommended removing protective cases during hot-weather drives, since silicone and plastic materials that guard against impact also block the casing from releasing heat.
Reducing heat while driving
A phone's processor and battery generate heat on their own during use, and built-in cooling systems can struggle to keep up in hot conditions, according to the report.
The main rule, Engadget said, is not to charge a phone inside a hot car, particularly with wireless charging, which is less efficient and produces more heat than a cable. Car mount chargers are convenient but can become an added heat source in summer, the outlet noted.
Engadget advised cutting back on device use in the heat: skipping continuous navigation on familiar routes, lowering screen brightness, turning off unneeded features like Wi-Fi, and avoiding resource-heavy apps such as games or video editing tools.
If a phone starts overheating, the report said the first steps are to turn it off and move it out of direct sunlight. Engadget cautioned against trying to cool a device quickly with a refrigerator or ice-cold air, since a sharp temperature change can allow moisture to form inside the casing.
