Iphone 11 PRO, phone suddenly shuts down and battery gets decreased

[Zirold]

Hey guys, I'm writing on behalf of my friend as she doesn't have account here. So she has Iphone 11 PRO with 15.5 IOS. Phone recently started to act weirdly, suddenly it can turn off itself and after we launch it, battery get lower by 10-30% comparing to time before shut down. We checked battery capacity but it shows 100%. At first I thought that maybe battery is old and needs replacement but with 100% capacity I'm not so sure anymore... Anyone had problem like that and knows how to fix it?


Here are two pics of battery, as you can see on this red bar, suddenly it went down so much, it was moment when device shut itself down.

 

[one more]

Unless your friend has recently swapped that battery, I would question that 100% capacity figure. If you have a Mac nearby, check it with CoconutBattery to get a better picture.

If the battery is indeed fine, you could try restoring her iPhone and see if it helps.

If it does not, you are probably then better off taking it to Apple or one of their ASPs, as it could have something wrong with its power circuit. For that reason, while you are figuring it out, maybe do not leave it charging unattended.

 

[Zirold]

Unless your friend has recently swapped that battery, I would question that 100% capacity figure. If you have a Mac nearby, check it with CoconutBattery to get a better picture.

If the battery is indeed fine, you could try restoring her iPhone and see if it helps.

If it does not, you are probably then better off taking it to Apple or one of their ASPs, as it could have something wrong with its power circuit. For that reason, while you are figuring it out, maybe do not leave it charging unattended.

Oki doki we will try to check it out with coconutBattery and see. Well she bought it refurbished so maybe indeed battery capacity isn't as it shows. I asked her to set this calibration thing but they say it might last few weeks. But anyway thanks for the tips and will try your solutions to see if battery capacity is not lying!

 

[one more]

Oki doki we will try to check it out with coconutBattery and see. Well she bought it refurbished so maybe indeed battery capacity isn't as it shows. I asked her to set this calibration thing but they say it might last few weeks. But anyway thanks for the tips and will try your solutions to see if battery capacity is not lying!

I see. If it was bought refurbished, then these battery numbers might be fine, as batteries are frequently swapped. If she has a warranty from the refurbishing place who sold her the iPhone, perhaps contact them as well.

 

[now i see it]

My iPhone 7 battery reporting went absolutely wonky for a few days after first installing iOS 15. It was all over the place.
Over the span of several days it finally settled down and now is stable

 

[jav6454]

Oki doki we will try to check it out with coconutBattery and see. Well she bought it refurbished so maybe indeed battery capacity isn't as it shows. I asked her to set this calibration thing but they say it might last few weeks. But anyway thanks for the tips and will try your solutions to see if battery capacity is not lying!

She bought it refurbished? From where? If she bought it from Apple, take it to them and have it serviced. If not, then go to the seller and see how to proceed with service.

 

[Splitrail]

Hey guys, I'm writing on behalf of my friend as she doesn't have account here. So she has Iphone 11 PRO with 15.5 IOS. Phone recently started to act weirdly, suddenly it can turn off itself and after we launch it, battery get lower by 10-30% comparing to time before shut down. We checked battery capacity but it shows 100%. At first I thought that maybe battery is old and needs replacement but with 100% capacity I'm not so sure anymore... Anyone had problem like that and knows how to fix it?

Did this trouble start before or after the 15.5 IOS upgrade?