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Use Appropriate iPhone Charger
Your iPhone comes with the correct charger, and you should use it. It’s tempting to use a more powerful charger, as your device will charge faster. Rapid charging increases thermal stress to the battery. I used an iPad charger on my iPhone in the past, and it was noticeably warmer when charging. I ceased this practice after learning it could shorten the battery’s lifespan.
Newer iPhones support rapid charging, however, Apple doesn’t directly endorse this practice. They ship the iPhone 6S and 6S Plus with a 1A charger, however, both devices are capable of charging at 2.1A.
Some people have figured this out and are charging their iPhone using the more powerful iPad charger. Apple’s website suggests that one can use an iPad charger for the iPhone. You can, but should you?
It’s well established that charging lithium-ion batteries with a more powerful charger will diminish battery lifespan. You have to decide whether rapid charging is worth it. Even if rapid charging doesn’t generate more heat, according to Battery University, it will permanently damage battery capacity. Using a more powerful charger will decrease battery capacity and the number of charge cycles. Although the iPhone supports 2.1A charging, the supplied charger is 1A. I strongly recommend using the included charger or one with even less amperage. Popular Mechanics makes this same recommendation.
Charge iPhone with USB 2.0
We’ve established that charging an iPhone with a more powerful charger will generate more heat, which diminishes battery lifespan. It’s possible to charge an iPhone with even less current than the provided charger. USB 2.0 puts out only 0.5A of current. Charging your iPhone with a USB 2.0 socket is much slower, but will minimize heat. If you charge your iPhone overnight, it makes sense to use a USB 2.0 socket. The only other consideration is that your computer may need to be turned on, which could increase your energy bill.
USB 3.0 puts out 0.9A of power. It is slightly less powerful than the 1A charger that comes with your iPhone. If you have a newer computer that doesn’t have USB 2.0, the newer USB standard will still provide less current than your iPhone charger.
Don’t Use Wireless Charging Mats
Wireless charging mats may seem convenient, but they will shorten your iPhone battery’s lifespan. The problem is that inductive charging loses up to 25% of the energy. This lost energy produces extra heat when charging. It also wastes power, but this will have a negligible effect on your electricity bill. If everyone used this technology, however, the wasted energy would be noticeable.
I personally don’t understand the appeal of “wireless” charging. You have to plug the charger into a socket, so it’s not wireless. It’s kind of like sweeping dirt under the rug. It may be slightly more convenient to place your iPhone on a mat, instead of plugging it in. It makes some sense at coffee shops, where several customers can use one charging mat. They could also just supply multiple charging cables. I’ve never experienced difficulties connecting my iPhone to the charging cable. When we can beam power across the room, I may be interested. That’s true wireless charging. (continue…)