Magnetic charging loses some energy in the form of heat on both coils.
Technologies like MagSafe lessen the severity of energy loss via ensuring the coils allign, however there is still some energy lost in the form of heat.
This is just a limitation of electromagnetic induction.
It’s a producer of heat placed right next to the battery.
This inefficiency also makes it take more energy to charge your battery. However, I would imagine it’s a nominal amount.
That’s an interesting theory. I’d like to see some numbers because I really doubt that this heating could be anywhere close to the many other kinds of heat produced through normal phone use. Especially considering that you’re unlikely to be stressing the biggest sources of heat in your phone (the screen and the processor) while it’s sitting in a wireless charging cradle. Also, the charging circuits certainly monitor and adjust for this kind of heat dissipation specifically and are able to control it far better than, for example, the sun hitting the screen or a warm pocket.
The charging circuit will maintain a “safe” temperature, sure, but using any battery monitor app you like, you can clearly see for yourself that when wireless charging, the phone will sit at a higher temperature during the process, than when wired charging. And every fraction of a degree matters. Not when you use the feature once, but if you do it every day, always charging at a higher temperature, it WILL shorten the lifespan of the battery. The same way every charge does, but to a slightly higher degree for every fraction of a degree in higher temperature.
The battery does not suffer as much damage from heat when discharging, or when just sitting there, not that that is good for it, either. But every extra bit of thermal strain WHILE charging, causes more damage than if it were running cooler. That’s simply a fact of lithium ion batteries.
I remember LTT wanting to find out the damage that wireless or fast charging does but found that the way we charge our phones mattered more or something: https://youtu.be/AF2O4l1JprI
I found the segment and may have summarized it incorrectly but I can’t rewatch the video entirely right now.
I can only offer you my experience-based evidence, but three magnetic chargers I’ve used have all made my phone significantly hotter then charging it at the equivalent speed with a cable.
This has been true across 6 Android devices. Two from Google. Four from Samsung. However, I will also say that because of this trend, I stopped using wireless chargers about a year and a half ago, so it’s quite possible they might have improved since then.
Yes, the tech has gotten a lot better. 6 phones over about 12 years (rough length of time since debut of inductive charging in smartphones) averages to about 2 years per phone. If you weren’t getting the flagship phone each year that lifetime would be shorter. That was comparable to the lifetime of each over my phone’s during that same time, none of which had wireless charging. The phone I have now is the first I’ve had to use inductive charging and it has already lasted twice as long as any of the others and shows now signs of deterioration.