If there's one thing that rechargeable batteries do not like, that's getting hot. According to Apple[1], iDevices are good operating in a range of 0º and 35º C (32º to 95º F), and the company warns that using its devices "in very hot conditions can permanently shorten battery life."
I'm quite fortunate that I live in quite a mild to cold climate here in the wilds of Wales, but I have noticed that I put my iPhone through thermal stresses several times a day.
And that's when I'm charging it.
Must read: iOS 14.1 rolling out to iPhones, but no sign of a battery fix[2]
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NEXT [5] PREV [6]I've been keeping an eye on how devices recharge -- especially iPhones -- for some time, and that's allowed me to build up some patterns, even how the temperature fluctuates.
Here's what I've noticed.
The faster the charge, the more heat is generated, and wireless charging also warms up the iPhone more than charging the iPhone with the supplied charger.
The longest time my iPhone spend son charge is overnight. I plug it in before I close my eyes and unplug it as soon as my eyes open. That's between five and nine hours a day.
Apple introduced a feature called Optimized Battery Charging in iOS 13, the idea being that when the iPhone is hooked up to a charger for extended periods -- specifically overnight -- that controls the charging so that the device is fast-charged to 80 percent, with the final 20 percent added in time for when you wake up (for me, charging is always completed before