iPhone 6(S)/Plus Never seen issue: 6s. New 98% battery and unexpected shutdown

[Racineur]

Hello friends. My faithful dinosaur has been acting weirdly. Battery heath is 98% with 12.4.1 running. This message appeared a few times and I've done manual resettings. But the message appeared again few days later. Last time this happened I had the phone in hands. Battery level was at 85% and it went down to 4% suddenly. Wasn't, doing anything. Just holding the phone. What could have happened? Reinitialize the phone but the message is still there. Also, please a few words on iOS 14. So many contradicting comments here and there. Would the 6s become unusable if I upgraded to 14.2? I tried 14 on a 2015 SE and it's doing OK in the battery department and UI but I use it only for listening to podcasts when in bed. Please, in a few words, should I stick to 12.4.1 or let the 6s end its days on 14? Main use for my iPhone is calls, Mail, Weather, Security in my car, Shopping app for groceries and Maps once in a while.
Thanks for your precious hints.

 

[russell_314]

Hello friends. My faithful dinosaur has been acting weirdly. Battery heath is 98% with 12.4.1 running. This message appeared a few times and I've done manual resettings. But the message appeared again few days later. Last time this happened I had the phone in hands. Battery level was at 85% and it went down to 4% suddenly. Wasn't, doing anything. Just holding the phone. What could have happened? Reinitialize the phone but the message is still there. Also, please a few words on iOS 14. So many contradicting comments here and there. Would the 6s become unusable if I upgraded to 14.2? I tried 14 on a 2015 SE and it's doing OK in the battery department and UI but I use it only for listening to podcasts when in bed. Please, in a few words, should I stick to 12.4.1 or let the 6s end its days on 14? Main use for my iPhone is calls, Mail, Weather, Security in my car, Shopping app for groceries and Maps once in a while.
Thanks for your precious hints.
View attachment 1677231

You can't always go by what it says the battery health is in settings. Unless it's a new old stock 6s it's not 98%. The phone will throttle down if the CPU can't get enough power. Apple was forced to make a switch in settings to disable that by greedy legal people so if you turn that off it will crash instead of throttle. I suggest installing something like coconutBattery on your Mac to check the battery.

 

[Racineur]

Hello and thank you. You're right. See below. Coconut Battery gives me 85.4% health compared to iOS dedicated info 98%. How can that be? So this is why the throttling. The battery was replaced in December 2018 on the Apple battery replacement plan. How could it lose its power so fast? The Phone is off 3/4 of the time. Can pass 4 days without being turned on. I don't like that. I think this is deciding me to have a newer phone. Will check Fido (Rogers) plans in Canada. Much a surprise and a big disappointment to me.

 

[PNutts]

When you say "new" in the title, is the battery new? You have the classic symptoms of a battery that needs replaced.

 

[Racineur]

I shouldn’t have mentioned « new ». I was rather referring to the fact this is the second battery installed in this 6s. So it comes to the point that I will have to part ways with my old friend.