How do I get my iPhone to recalculate battery health?
My iPhone 14 Pro has been at 84% battery health for almost a year now. Anecdotally the battery lasts significantly less time than it did previously, even when it was already at 84% health. I think it may just be a stale calculation, and my actual battery health is significantly lower. If I can get it to show as less than 80%, I can get AppleCare to replace it. Does anyone here know how to get the iPhone to recalculate this value?
I have Coconut batter on the Mac, and it can check the battery health for an iPhone attached with a cable. It uses a different formula, so it gives me a health of 87%. However it also shows history for when I have run it in the past, and when I tested it almost 100 charge cycles ago, it also read 87%. I don't know how any battery can go almost 100 charge cycles with zero degradation (537 to 617 cycles, so it's not like it's a fresh battery).
I've worked at Apple as a repair tech. Simple answer: You can't. It runs the calibration routine every time you fully juice up from dead, so you can at least force that, but there's no guarantee that'll show on the readout. Similarly, if you go to an Apple store and ask them to run an MRI on your phone - a basic function test, Mobile Resource Inspection - they can get that number, but you can't, at least not easily.
THAT BEING SAID, however, you're at 84%. That's kind of a magic number for iPhones, and it always has been, and even technicians decades my senior don't seem to know why. The iPhone just likes staying at that battery health level (or 83, i've seen that too) much longer than it would seem it's able to. I'm willing to call it an idiosyncracy, it happens, nobody knows why. When it eventually does go down, there's a good chance it'll jump straight to 79%, at least that's what the data we've collected at my apple store seems to corroborate. Don't think Apple ever acknowledged that in any official capacity, the repair manuals make no mention of this behaviour.
If you wanna go the hard route, you can of course aggressively mistreat your battery. Put it on the radiator in your house while charging, or on a heated car seat. Charge whenever you can, especially above 50%, turn off the Optimised Charge setting in the menu, that sorta stuff. It's not gonna make the thing explode or catch fire, but it will reduce its life expectancy. But from my experience, 84% will stay a while.
Fantastic! I knew someone here would have some insight. It's really weird that this is a common enough issue that it is well known in the tech community. At least I am not crazy.
Thanks for the info about the MRI (and I like that acronym). I don't think I will try to ask Genius Bar for that, simply because I am in France right now, so there is a big language barrier with a local Apple Store.
I have turned off Optimized Charging, but every time I have looked at the battery menu in the past few months, it doesn't seem to actually have optimized even though it was turned on. I know it worked in the past, so I guess my current usage is unconventional enough for it not to work. I usually charge overnight with a wireless pad (off brand, not MagSafe), so I am thinking that maybe it needs a cable charge for certain functions to work? Anyway I am going to try some 0% to 100% charges with a cable and see if it works. I downloaded antutu benchmark, which heats it up and drains the battery pretty well, so I can get down to 0% pretty easily.
I read on reddit that the battery health metric is just based on charge cycles, not actual health. If that is true, doing the heated battery stuff will degrade the battery without affecting the metric. I presume that this is false, and it is based on actual battery health. Do you have any insight into this? I am guessing it's something that apple doesn't tell anyone, let alone repair techs.
I'll say that I was just a repair tech, not an engineer and certainly not a hardware designer. I can't tell you definitively if it's just cycles, but I have a strong suspicion that it isn't - MRI also reports (at least if you start the test from a Mac with the Diagnostics dongle and not just the web version they run on their iPads through the GSX service portal) cycles, max capacity, design capacity and current capacity in Ah. Since they obviously collect that data I suspect it's not simply a lookup table with number of cycles.
Anecdote: When I got a new phone and was still with Apple, I ran a test to check if everything was all right and it reported as one cycle, 100% health, 2400 mAh maximum capacity, 2400 design capacity, but 2473 actual capacity. Makes sense to me, batteries are imprecise things that use chemical reactions to work, so I believe this is not calculated through cycles but cap readings.
Hmm, that does seem surprising. Though I’m not aware of anyway to force a recalculation, and I would expect coconut battery to be accurate.
If it feels bad, perhaps it’s just time to get a new battery? I had the battery in my 12 replaced a few months ago and it’s really given it a new lease on life (I was considering upgrading to the 16, but instead decided to replace the battery and wait another year. Seems like a good value proposition.)
If you think about it, if by replacing the battery you can hold onto the phone for an extra one or two years, then it’s very good value.
Based on my experience, 84% is considered anywhere from fine to terrible. I was at 84% back in August, and the battery life was almost unchanged from new. But now at 84% the life feels way worse than it was new.
Take a look at what /u/delphi commented. It seems like 84% is a weird magic number that iPhones get stuck at. Anecdotally, the health metric seemed perfectly accurate until it got to around 86%, and then stuck at 84%. Either way, I wouldn’t worry about 96%; that is really good for a phone that old.
I had a very similar thing occur a few weeks back - my device was on 86% battery health for the longest time, but one weekend it finally ticked down to 85%. Two days later, and it dropped to 84% and has stayed there ever since. I have a 13 Pro, so I'm happy that it's lasted as long as it has, but I don't trust the battery health percentage anymore, as there was a very noticable drop in longevity despite the health staying at 86% for at least 6 months.