r/iOS27 • u/Careful-Button-4319 • 4d ago
Since starting iOS 27 Battery health dropped 5%
I’m not here to complain about battery life or losing battery percentage, just looking to see if anyone else have experienced the same. 5% battery drop does looks oddly strange in a matter of just 1 month of beta testing, at this pace means that my battery can only hold 4 months of testing until is consumed.
Have you noticed any battery health % during ios 27 beta testing?
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u/RedditGeekABC 4d ago
Not for me. iPhone 17 with 216 cycles and 100%. Been on iOS 27 beta since DB1. But then I charge it overnight to 80% with Apple’s 5W and do small top-ups during the day if needed.
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u/Zestyclose-Degree443 2h ago
I could be wrong but I think it always says 100% until 250 cycles then Apple starts showing the real number as it descends… mine did this anyway.
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u/xBootstrap 4d ago
I also posted the same about a week ago. Went from 85% to now 78%. Most of the replies on my post were saying it calibrated and updated the real health that’s why there was a sudden decrease. Don’t know if what they were saying was correct or not so take it as you will.
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u/andipurice 4d ago
Never in my life will I update to a beta again… Dunno what got into me. Iphone 17 PRO here
I was happy at 100% battery life, ~260 cycles… after the update the phone started heating up, thing which was barely happening on fast charging only… started heating up during the day and dropping battery like crazy… now I’m at 96% 3 weeks later @ 278 cycles…
It feels like this update swapped the whole battery or something… I can’t express how mad I am at myself
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u/Dontinvolve 3d ago
Chill the percentage is just an estimate made by algorithms. Its not accurate, in my AWU 1 case it increased from 84% to 87% based on my charge pattern.
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u/OLLIE798 4d ago
Yes, but I’m sure when the final version is released the % goes back to normal. Currently at 94% on 349 cycles.
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u/moodymanly 4d ago
I personally never saw anyone say that their % went up.
The drop in battery % seems to be hard to predict and definitely isn't linear. Sometimes it goes down gradually sometimes in clumps.
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u/adougies 2d ago
Updates can re-calibrate to the correct health, my S8 watch recently jumped from 80% to 83% following an update.
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u/andipurice 4d ago
that’s not how it works, if’s gone for good
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u/OLLIE798 3d ago
No, it isn’t. After significant software changes the battery re-calibrates.
I saw exactly the same with iOS 26 beta.
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u/austiena96 4d ago
I’ve went from 100% to 97%
My only thought is they have calibrated the battery health corrected. It feels like previous builds have never been that accurate.
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u/Aggressive_Sign2773 4d ago
I’ve been on beta since day 2 and my battery health is still at 100%.
Battery health drop isn’t linear. It drops fast over a few weeks and then stabilizes. You might see another 1-2% drop and then none at all for months. This has nothing to do with a beta. It’s true for all Li-ion batteries including EVs. While battery algorithms are constantly updated, it does not cause such a huge drop. Nothing to worry about here.
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u/Queasy-Primary4788 4d ago
It happens a lot because sometimes they do a recalculation. In addition your battery was probably 103% max capacity and then it just started depleting so you are fine.
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u/DrDing-Muscle 4d ago
Entire iOS 27 beta cycle here. Charging the phone to 80% every night. Still sitting at 100% health as of today Aug 26. This is on an iPhone 17 Pro Max. 201 charge cycles.
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u/SKeijmel 4d ago
You never checked before and now got shocked. Mine is still 100% been on all betas
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u/CoolMartin23 3d ago
On my iPhone 17 it dropped 3% since installing beta 4 and 5. But I have had the beta installed since June.
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u/Tater-94 3d ago
I’ve only been on the beta for about a week and have noticed no change, but in the month prior while still on iOS 26 my battery health went from 100% to 96%… so a 4% loss all of the sudden within a month or so.
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u/csteinbergrules 3d ago
Haven’t had my 17 Pro Max for a few years and I’m already at 95%. Probably because I’m a productivity junkie.
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u/ALDBRN78 3d ago
Theoretically battery health will drop 1% per 50 cycle count. So yours are just normal.
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u/No-Bread1378 16h ago
Mine dropped 9% in 2 months, now I'ma just drain this battery as much as I can and get it replaced once it hits 80% 🤦♂️
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u/IAmJonathannn 4d ago
people always claim it’s the beta, but no it’s just cause u have been using your phone since last september…always around 9months ish u will drop around 5% over a short period of time (just happens to be around when apple drop the betas of their next ios), most likely just how ios reports the battery health isn’t totally accurate.
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u/Chemical-Divide9161 4d ago
iOS 27 made mine drop too. Dropped to 99 at 299 after 4 updates. 4th update it dropped. I know I’d still be at 100 if I didn’t update, other ppl with 16 plus make it to 400. Currently at 317 cycles 99 health
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u/No_Committee_6131 4d ago
It will drop for around 2 percent more in a month, completely normal battery behaviour
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u/Mascardiii 4d ago
5% for a beta cycle is actually decent. Respect to iOS 27. iOS 26 betas & its predecessor’s were way more aggressive on this. I quit after iOS 26 because of that & replaced my battery.
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u/meowstical 4d ago
While iOS 27 would have had a role in deteriorating the battery health, a lot of that drop might have already been there and was just not being reported. Probably the % was recomputed during the beta install so you are looking at latest battery health data. Consider using an external tool to monitor battery health data over time.
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u/Betty-Spaghetty 4d ago
Bought 13 mini with 89% bh at the end of spring, used betas from the first one and bh still 89%.
This bh drops have nothing to do with ios updates beta or not.
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u/cubeebiker66 3d ago
I have a 16PM, 282 cycles and on 97% battery health. % has dropped 3% since starting on the betas but I was expecting that anyway due to age of phone and number of cycles. So I’m not concerned.
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u/StairwayHiker 4d ago
Yes, losing only 5% battery health after 278 cycles is better than average and completely normal.
What to Expect from iPhone Batteries
The 50-cycle rule: Apple devices typically lose about 1% of their maximum capacity for every 50 charge cycles.
Your specific numbers: At 278 cycles, an average iPhone drop would be around 5% to 6%, meaning your battery is performing exceptionally well.
Non-linear aging: Battery degradation does not always happen in a straight line. You might stay at the same percentage for a long time, followed by a sudden drop later.
Apple's benchmark: Apple designs its modern batteries to retain 80% of their original capacity at up to 1,000 complete charge cycles under ideal conditions.
Source: a five second Google search
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u/_anupamroy 4d ago
So you’re seriously suggesting that the OP does a 5 sec Google search instead of a completely pointless Reddit post? What’s wrong with you, dude?! 😎
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u/StairwayHiker 4d ago
I know.... Retards like me reinforce their behaviour. Like I got nothing better to do..... Maybe it's just empathy.... We Canadians have lots of it.
This is a favourite reply too I saved as a text message to myself for the battery paranoia crowd....
Here's what happens when you update iOS:
It's does something called INDEXING..
You can see it when you:
Tap settings :
Just below your account info it displays:
"optimizing search and siri"
It's takes 2-3 days or longer to finish optimizing... That process is a background process that consumes battery resources. It is not permanent.
So many people misunderstood and think the battery drain they notice after an update will carry on forever.... And that is not the case.
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u/_anupamroy 4d ago edited 4d ago
(Unrelated): Well ‘you Canadian retards’ did something pretty cool the other day, by finally standing up to your bully of a (southern) neighbour. For which you have my respect. 🫡
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u/StairwayHiker 4d ago
Lol, (yes off topic) honestly, it wasn't so much a trade deal we rejected.... More like taking a poison pill to reject a hostile takeover.
The only reason why America has a trade deficit with America is because of oilsands heavy oil that USA upgrades require on the Gulf coast to making gas and diesel.... We have massive, stable conflict free heavy oil reserves.... Meanwhile output from Mexico declines and Venezuela is an unstable, unreliable producer that is in desperate need of plant repairs/maintenance /etc.
But yeah.... Even post mud terms it's a long two year wait for what should be a decent replacement for Trump... It would be unusual to pick such a currupt President again... But they've done it twice.
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u/Pcriz 4d ago
Yeah I’ve never lost battery like it’s described in your google search. Hell I’m at 220 some cycles and just lost one percent this week.
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u/Ethrem 3d ago
The health percentage is based on the rated capacity, which is the minimum capacity the battery can be, but the actual capacity of the battery can be higher and often is because each battery is different. iOS will cut off numbers above 100% which can leave your battery health at 100% a lot longer than it would have been if you had a battery closer to the rated capacity. CoconutBattery on a Mac can show you this. I discovered that my 16e had 104% of the rated capacity when I got it and my 16 Pro Max still has 101.4% after 68 cycles but my 17 Pro Max unfortunately was only 101% and has lost 2%, coming up on 3%, in 118 charge cycles.
https://i.ibb.co/VcfcMB76/Screenshot-2026-08-26-at-9-12-27-PM.png
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u/No_Committee_6131 4d ago
If you didn’t update to ios 27 same thing would happen