iPhone 11 Pro iPhone 11 Pro battery won't budge below 80% even after 8+ months

[hardwickj]

Since December of last year, my iPhone 11 Pro has been sitting at 80% battery health (Settings -> Battery -> Battery Health -> Maximum Capacity). I originally bought the phone in October of 2019, so ~34 months ago. That would imply 1.7 months per 1% decline in battery health, assuming it's a perfectly linear decline (admittedly unlikely).

It's now been 8 months since hitting the 80% health mark. If I exclude that past 8 months, the average per 1% decline then becomes 1.3 months. So the amount of time it is taking for my phone battery to decline 1% more (to reach 79%, the point at which AppleCare will replace the battery for no charge) is taking more than 6x longer than average.

This smells remarkably fishy.

Anyone else out there noticed this?

 

[tomcoppard]

Hello.

I understand the iPhone 11, Pro and Pro Max have incrementally bigger batteries but they're all designed to last 500 charging cycles (100% charge = 1 charging cycle). If I recall the iPhone 11 and possibly others had issues when iOS 15 came about with Battery Usage - battery health was displaying erroneously due to software issues not hardware issues. So point 1 could be its a software issue.

I didn't observe or measure the issue as you have done but with the iPhone 6s, its fair to say the first 20% health drained quickly and then each percentile took longer and longer to fall away. So point two: it could just be typical as-by-design iOS behaviour and maybe, as you say, its a bit fishy. You would expected to be using more charging cycles as time goes by because their is less battery to charge perhaps?

My advice would be to visit an Apple Accredited provider to check how many charging cycles the device has gone through - if its hit over 500 (which the provider will be able to tell you) there might be some wriggle room - given the aforemented known battery health weirdness.

I look after about 5,800 live iPhone 11 devices which were deployed June 2021 - so in the next 6 months I expect to see users start to gripe about batteries (we don't have Apple Care or extended warranty of any kind). Previously we had the iPhone 6s deployed and saw degraded performance about 18 months in. Interesting to hear you say your device reached 80% after 2 years 2 months worth of usage - that doesn't sound too bad going but it does mean i might have a pandemic on my hands sooner rather than later.

 

[hardwickj]

@tomcoppard that is some excellent information. Thank you!

According to coconutBattery, my battery has gone through 615 cycles. At this point I'm unable to make it through most days without recharging, sometimes needing to twice. About 6 months ago I went to an Apple Store and asked them about replacement but they said it needed to be below 80% for them to do so. I'm wondering if I went back now and showed them this same data if they'd finally do something about it.

 

[OhMyMy]

Have you tried leaving it in a hot car for a few mins and charging with a fast charger to bring the health down?