Charging a cell phone is something we do regularly, every day of our lives if we have one. There are many different ways to charge mobile phones, and most people use the typical wall charger: that little plastic block that connects to the wall socket, and then plugs into our phone to charge it.
Something that people notice a lot, and makes them kind of nervous is that the cell phone charger gets hot when it’s charging. This heating up is pretty noticeable: it’s not just that the charger gets slightly warm, it actually feels hot during the charging cycle.
After last year’s “explosive” problems with the Samsung Galaxy Note 7 and all the press coverage they received, it’s normal that seeing your cell phone’s charger get hot would make you uneasy.
But, don’t worry! It’s normal for your cell phone charger to heat up! Let’s explain why mobile phone chargers get hot, and when you should be careful …
Why do cell phone chargers get hot?
A mobile charger is a power source, which takes the voltage from the wall (usually 110 or 220 volts) and converts it into a voltage that can be safely used by the cell phone (about 5 volts). This conversion process generates heat, because the voltage conversion is not 100% efficient. There’s always some energy that turns into heat: how much energy depends on the charging circuit in your phone and the parts inside the charger.
Cell chargers are small and compact, and this concentrates heat sources. The heat usually comes from one or several chips, that are clumped together inside the charger. Manufacturers put these chips near the plastic cover on purpose, so the heat can escape. End result? Heat’s going to flow pretty fast outward from that point, and your phone charger is going to heat up in a specific point, before the heat starts to spread and dissipate.
That makes your phone’s charger get pretty warm, especially when you’re charging a phone that has a lot of battery capacity and quick charge.
Some users find that switching their charger, usually to one with less amps, stops the heating. Yes, it works, but obviously because the cell phone slows down its charge cycle, and makes less energy pass through the charger. The charger doesn’t heat up so much, but charging is going to take a lot longer. A lot of phones will even warn you that they’re in “slow charge” mode if you put a lower capacity charger on them.
Cell phone chargers and battery packs getting warm is normal, and it’s simply an effect of the voltage conversion that occurs within these devices. It should be of no concern.
Of course, heating has to be moderate: your charger is going heat up, but not enough to reach burning temperatures. You should still be able to handle the charger comfortably, and it should never cause damage to nearby surfaces.
If your charger gets too hot to touch, or if the plastic surfaces start to warp, that does indicate a problem. It could be a serious electrical problem inside the phone or the charger, and maybe even a fault in the battery protection circuit. If this happens, unplug your charger and replace it immediately. And then take your phone to a repair center to get checked, just in case the problem is with the phone or battery itself.
Remember that a charger that’s not working right can supply the phone with voltages that are too high, or have excessive electrical noise. That can damage the phone and battery, and could even lead to a critical condition that might cause a fire or explosion. It’s not worth it to risk something like that… so if your charger ever gets too hot to comfortably touch, replace it. Period.