Photo remixed from an original by Shutterstock.
First of all, this is normal behaviour, and something that happens to pretty much every phone. This heat is coming from your phone's battery, which usually heats up when you're drawing power at a faster than normal rate — say, when you're in a phone call, using GPS, or watching a video. If your phone gets so hot that it's powering down, then you might have a faulty battery — but otherwise, your biggest problem is that the phone just becomes uncomfortable to hold. And, if your battery's hot, it means you're draining that battery quickly, which is never good.
Here are a few steps you can take to make sure this doesn't happen as often:
- Turn off battery-draining apps: Make sure you have Maps closed when your phone is sleeping, make sure your phone isn't constantly searching for signal, and so on. Battery-saving apps like previously mentioned JuiceDefender for Android can help with this, and closing all those running apps on your iPhone could help too. All in all, make sure you're taking the necessary steps to use your battery efficiently.
- Watch out for runaway processes: Sometimes, an app just gets out of hand and starts eating your CPU for no reason. Or, sometimes, it's just poorly written and eats up more CPU than it should, which in turn eats your battery. Previously mentioned Watchdog will help you keep track of these on Android, so if you're phone's heating up and you don't know why, it might be able to give you a clue.
- Don't stifle your phone: If it's burning a hole in your pocket, take it out of your pocket to give it some air. If you're watching a video, use the phone's built-in kickstand or a DIY stand. If you regularly use the turn-by-turn navigation, I can't recommend the binder clip stand enough — it holds your phone up at the perfect level for navigation, and puts it right in front of the air conditioner. Even after an hour of using the GPS, when my phone should be piping hot, it's always cold to the touch.
- Take it out of the case: This kind of goes in with the last one, but is something you can do in almost every overheating situation. If you have a case on your phone, take it off. Certain cases will insulate heat far more than others, and removing it could give your phone a chance to cool off a bit.
- Don't overclock your phone: Overclocking your phone is a good way to get some extra speed out of it, but it's going to use more battery and heat it up faster. Previously mentioned SetCPU can create profiles, in which if it gets to hot it scales back the overclock, which is nice. You can also just use SetCPU to underclock your phone if you're having constant heat problems.
If your phone overheats to the point of crashes or random shutdowns, you'll want to take it in for a warranty replacement, but if it's just getting too hot to handle, the best you can do is stop taxing your phone and to give it a bit of airflow. It isn't the perfect solution, but armed with the knowledge of why this is happening, you should be able to stop it from heating up so darn often.
P.S. Got any of your own tips for cooling off a hot mobile phone? Share them with us in the comments.