I tested 3 wireless chargers to see which keeps my phones cool - what I learned surprised me

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Magnetic wireless chargers use different methods to fight heat.

I tested three different stations to see which works best.

The results were surprising.

To those of us who have been longtime fans of wireless charging -- even going back to the days of the Palm Pre -- one thing has remained certain: When you pick up your phone, it's going to be warm.

As it turns out, transmitting electricity through the air is going to heat things up, and that can be not ideal for your battery. When I got on the phone with the folks at Mophie, they were excited to tell me about its new charging stand.

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According to CMO Brian Oleska, the 4-in-1 charger features StealthCharge Technology, which is Qi2.2-certified for 25W of wireless charging. But it passively keeps your phone cooler by positioning most of the charging components away from the charging pad and in the base of the stand. The metal of the stand acts as a heat sink, keeping your phone cooler.

As for the charging coil, it comes with its own heat sink. In theory, this keeps your phone and its battery cooler overall, and it's also silent -- there's no fan cooling the charger.

Testing with Apple and Google

So, I wanted to test it out.

Mophie sent the 4-in-1 charging stand, which includes a watch charger, an additional Qi pad for AirPods, and a retractable wired cable as well. I tested this charger against a Ugreen Qi2 25W Magflow wireless charger, which monitors the temperature of the phone to prevent overheating, and an ESR Qi2.2 3-in-1 charging stationwith its CryoBoost fan-cooling technology.

To conduct the test, I used an iPhone Air and a Google Pixel 10, both of which have integrated magnets in the back of the phone to support Qi2.2 charging. The iPhone Air supports up to 20W of wireless charging, and the Pixel 10 supports up to 15W. Of course, we've learned that the wattage advertised by phone companies isn't necessarily what you're getting.

For testing, I discharged the phone to somewhere below 20%, and I charged the phone for 30 minutes using each stand.

Then, I measured the heat of the charging pad on the charger itself, the back of the phone (on the logo), and the camera bump with a thermometer gun. I measured the camera island on each phone for different reasons.

The iPhone Air famously keeps its processor (and basically everything else) in the camera pill, while the visor on the back of the Pixel 10 is the only metal component on the back of the phone, so if there's a good place to find heat, it's there.

Here's what happened

Of the three chargers, the ESR kept both phones cooler, with temperature increases of 13.1 and 14.8 degrees Fahrenheit for the iPhone Air and the Pixel 10, respectively. That's not surprising, since it uses an active cooling mechanism (read: a fan). According to Mophie, the benefit of using its charger is that it's silent since there is no fan.

Practically speaking, the fan in the ESR charger is basically a non-issue. Yes, there is noise, but it's incredibly faint.

The Mophie charger kept the charging pad and the iPhone Air cooler, but the Pixel 10 and charging pad were cooler on the Ugreen charger than on the Mophie charger. The Ugreen charger doesn't have a cooling mechanism except for an internal heat monitor that can adjust charging levels on the fly. Then again, that's with an Android phone, and the Mophie charger is designed for the iPhone.

From an engineering standpoint, I'm not 100% positive what difference that makes.

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Finally, just for fun, I plugged in the iPhone Air to a wired charger for 30 minutes.

It charged 44% of the battery, and it increased the temperature of the battery by 17.1 degrees -- about the same as the Ugreen wireless charger -- and it increased the camera island temperature by 23.9 degrees. So, overall, wired charging heated up the iPhone more than any of the wireless chargers, which makes sense, but I never really thought about it before.

Overall, it makes me wonder if heat is really the problem. Now, I'm not so sure.

But what I have learned is that the method by which your wireless charging stand tries to dissipate heat isn't as important as other things, such as whether it can charge other devices and how portable it is overall. At the end of the day, a charging phone is going to get warm, and there's not a heck of a lot you can do about it.