I believe current battery technology is optimized for fast charging. You are incurring damage every time your battery goes below 20% or exceeds 80% (see current EV charging recommendations).

Even LinusTechTips did a video that showed the length of charging doing more damage than fast charging. For the concern about thermal damage, most phones will throttle their charge if they become too warm.

Personally, I feel my wireless charger in the car does the most damage. It generates more heat and holds the battery in a charging state for longer

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arvinsim 3 days ago | parent | next [-]

I agree. I started using wireless charging with my iPhone 15 Pro Max. After a year of use, I am already near the 80% max capacity.

My previous phones never even got below 90% in their lifetime.

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jwr 3 days ago | parent | next [-]

Are you using high-power wireless charging? Does your phone heat up significantly?

As a counterpoint, I've been using low-power wireless charging (5W adapters) with my phones for the last several years (three phones at least). The battery degradation was minimal, I was able to pass my phone to my kid after 3 years of use with near perfect battery.

The key here is to prevent heat buildup.

	▲	arvinsim 3 days ago \| parent [-]
		Yes, I am using the high powered ones.

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CraigJPerry 3 days ago | parent | prev [-]

Same phone 89% on 535 cycle count, manufactured july 2023, first used september 2023. Almost exclusively wirelessly charged every time.

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red369 3 days ago | parent | prev [-]

Thanks for bringing up that LinusTechsTips video - I'll try and track it down. I would not have expected that conclusion. I've already said in another comment on this thread that I'd expect the opposite!

	▲	red369 a day ago \| parent [-]
		This seems like the video that the GP post was referring to: https://www.youtube.com/watch?v=AF2O4l1JprI Linus is surprised that fast charging does not heat the battery as much as expected. I interpreted that "length of charging doing more damage than fast charging" meant that slow charging was worse, because the battery spends more time charging, but I don't think this is stated in the video. In the video, Linus confirms that it is the high state of charge that does the damage and that trying to keep the state of charge as close to 50ish % is best. The conclusion that fast charging is better for the battery, is because you are more likely to do it when awake, and can stop the charging once it reaches whatever percentage you require (but the damage really starts to increase above 80%.