When charging a phone wirelessly, there is sometimes significant heat generated. That combined with higher charging rates that are now coming out with the Qi 2 standard make me wonder what the ideal charge for the battery would be.
Most of the time I just toss my phone onto a wireless charger before bed, and don’t really care how quickly it charges. Would it be better to use a 5W brick with a charging pad? Should wireless be avoided and usb used instead?
Technically, wired charging degrades the battery less than wireless charging, mainly because of the excessive heat generated by the latter. The same way slower wired charging generates less heat. Lower and upper charging limits also help (the tighter the better).
But I personally don’t bother with it. In my experience, battery degradation and longevity mostly comes down to the “battery lottery”, comparable to the “silicon lottery” where some CPUs overclock/undervolt better than others. I’ve had phone batteries mostly charged with a slow wired charger degrade earlier and more compared to almost exclusively wireless charging others. No battery is an exact verbatim copy of another one. Heck, I had a 2 month old battery die on me after just ~20 cycles once. It happens.
Sure, on average you might get a bit more life out of your batteries, but in my opinion it’s not worth it.
The way I see it with charging limits is that sure, your battery might degrade 5% more over the span of 2 years when always charging it to 100% (all numbers here are just wild estimates and, again, depend on your individual battery). But when you limit charging to 80% for example, you get 20% less capacity from the get go. Unless of course you know exactly on what days you need 100% charge and plan your charging ahead of time that way.
Something I personally could never be bothered with. I want to use my device without having to think about it. If that means having to swap out the battery one year earlier, then so be it.
Yeah I got lucky with my battery; it’s at 800 cycles currently and still holds plenty of charge for my daily use. A replacement kit is also only $50 so I figure there’s not much point in trying to be efficient for a marginal lifespan improvement. I’ll probably end up replacing it when it hits 1000.
Additionally, if you follow the “stay between 20% and 80%” advice, you’re only ever getting 60% of your battery’s capacity.
Why not just use it normally and get 100% of it? And then sure, in 3-5 years the battery may have degraded down to only holding 60% of a charge, but that means you’re effectively in the same boat as above, except you got way more usability from the phone in the meantime, and you’ve not had to spend time stressing about your battery.
There’s also nothing stopping you from spending £40-60 and getting a new battery after 4-5 years.
Because in 3-5 years I can just press a button and magically have 100% again when I need it. It’s not the same boat at all.
The real question is why would you deliberately accelerate the degradation when you don’t need it?
I already explained why you’d want to… So you get more use of your battery, and you’re not having to think about your battery.
It’s about usage patterns. If you know you only need 60% of the battery, charging it to 100% will degrade it more, for little utility. The newer Google phones get 7 years of updates, but without due care the battery will reach 80% of its capacity before that. On an aside, a battery is considered to have reached its end of life at a capacity reduction of 20%, and not 40%.
If you 100-0 the battery every day, then there’s not much you can do. But if you’re a lighter user, then using the 20-80% (or 40-60) part instead of the 40-100% part of the battery makes it last longer. And that’s good in terms of environmental sustainability, reduction of e-waste, and you can use the phone for longer, too.
The main thing (by far) degrading a battery is charging cycles. After 7 years with say 1,500 cycles most batteries will have degraded far beyond “80%” (which is always just an estimate from the electronics anyway). Yes, you can help it a bit by limiting charging rate, heat and limit the min/max %, but it’s not going to be a night and day difference. After 7 years with daily use, you’re going to want to swap the battery, if not for capacity reduction then for safety issues.