If you’re like most people, you’ve probably worried about dropping and breaking your cell phone, leaving yourself incommunicado. But you may not have thought much about the battery. Cell phone batteries are pretty durable, but if something goes wrong, they can malfunction and overheat — with surprising consequences.
Though your cell phone probably won’t explode, it might get damaged. “Batteries pack a lot of power into a small area,” says John Drengenberg, consumer safety director at UL. “If something does go wrong, causing a short circuit, the battery can pass a current internally that can heat the internal chemistry of the battery,” he says. What’s more, says Drengenberg, heat causes expansion, and that can cause breakage internally.
“That’s why a lot of batteries have a mechanism to notice heat pressure and allow it to escape, like a teapot that whistles.” Your cell phone battery isn't going to whistle, but having this feature enables the phone to cool down more effectively.
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To help keep the battery from overheating, never keep your cell phone in these places:
1. Your back pocket. Sitting on your phone could cause the phone to flex slightly, which could cause problems for both the phone and the battery. “Don’t do anything that would crush the phone,” says Drengenberg. That includes placing the phone at the bottom of a bag of heavy books. The pressure could cause the battery to expand and potentially burst, says Scott Wolfson, communications director of the Consumer Product Safety Commission.
2. Your glove compartment. It may be fine to do this in cool weather, but it’s a definite no-no in warmer weather. Likewise, it’s fine and even smart to throw your phone in the trunk if that keeps you from texting and driving, but don’t do it in the summer. (If you live somewhere cold, don't leave your phone in the glove compartment or trunk too long in the worst of winter; extreme cold — temperatures below 0 degrees Fahrenheit — is bad for cell phones, too, because the parts inside can contract.)
3. Your beach towel. The sun can “fry” your cell phone just as it fries your skin. Keep it in your beach bag in the shade and focus instead on your book or the ocean.
4. Next to the stove. You may like your cell phone to be within reach at all times, but make an exception when you’re cooking. Keep it away from the hot stove.
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More ways to protect your battery
Make sure the battery doesn’t come into contact with metal. It’s fine for the phone itself to touch metal. But if you happen to be carrying an extra cell phone battery in your briefcase or bag and it’s near loose change or keys, the metal can touch the electrical connections and cause a short circuit.
Power down if the phone heats up. If you notice your phone getting hot while running certain apps, it’s likely okay. If the phone gets too hot to touch, however, shut it down and get it serviced. It may mean something is amiss.
Make sure your battery and charger are compatible. Other charges may fit your phone, but the manufacturer has tested only the charger that came with the phone.
Use only the manufacturer’s original battery or replacement battery. “Most of the major manufacturers of cell phones use batteries that are tested by UL,” says Drengenberg. Cheaper batteries may not conform to the safety features that keep batteries safe. “If it’s certified by UL, it’s gone through all kinds of tests, shock tests, dropping tests, charging tests,” says Drengenberg.
Try not to drop the phone. A near-impossible feat, perhaps. If you do drop the phone, if the impact was hard enough to damage the phone, you may want to bring it to a service center to inspect to make sure nothing came loose. “If the battery and phone overheat while the phone is off after it has been dropped, that could be a potential sign that there is damage to the battery,” says Wolfson. Use a good case to protect the phone if (when) it drops.
Definitely don’t drop it in water. “Water is the enemy of all electronics,” says Drengenberg. If there’s a chance that water seeped inside (which may depend on how quickly you retrieved it) and it still works, you should get it looked at. A service center can dry it out so there’s no corrosion later.