IPhone 6s Battery issue

Hope I can get some help here regarding my wife’s iPhone. Last year around Christmas we had the battery replaced as Apple was giving a discount on battery replacements. But recently my wife has been encountering a problem where her phone is suddenly at 3% charge and then the phone shuts down. But when she gets back home and plugs it in, it turns on and it’s at 70% or something like that. It’s a very strange issue. Has anyone heard of this problem before? I wonder what they would tell us if we went to an Apple store, I wonder?

It’s a bad battery. That is exactly how iPhone’s react when the battery is dying (although I have never seen one of mine go as high at 70% after plugging it in). When the battery is old/going bad, it has trouble reading it, so you get these wildly fluctuating levels like that. Obviously it shouldn’t be dying so soon, so that is strange. I would take it in and see what they say. Do you have paperwork from when they did it last year?

I don’t think you have this option on that old of a phone, but under settings>battery is there a “battery health” selection?

Yes, battery health is good. Still at 92%. I also noticed this message on her phone about peak performance capacity. It also seems to happen when she’s out of the house. I wonder if it’s a cold weather issue?

Hmm… The picture doesn’t seem to want to post for some reason. Anyways, it says “This iPhone had experienced an unexpected shutdown because the battery was unable to deliver the necessary peak power…”

Well that is strange then. I wouldn’t think it’s the cold. I have had various phones out in the cold for long periods and never had anything happen with the battery.

Definitely take it in. Or is she eligible for a new phone for cheap through your carrier? A 6 is ancient. :-)

We bought it outright. I think it’s cheaper in the long run as you’re not paying for outrageous plans. Maybe it’s time to get with the times and upgrade to an iPhone 8! Lol

Sounds like a reaction to cold to me. Are we talking like low 40s here? ( ~8C?)

It’s below zero C in Toronto these days. -5°C

That would still take hours to have an effect. When I was stationed in Greenland we would do a lot of hiking and photography in below freezing conditions. It would take hours before the camera batteries would start to react. And then they would just die until warmed up.


Apple has determined that a very small number of iPhone 6s devices may unexpectedly shut down. This is not a safety issue and only affects devices within a limited serial number range that were manufactured between September and October 2015.

If you have experienced this issue, please use the serial number checker below to see if your iPhone 6s is eligible for a battery replacement, free of charge.

This exact thing happened to me whenever I left my phone out in the car for a few hours (like between getting to work and lunch, or between lunch and leaving work for the day) when it’s cold outside. I’d plug it in and it would come back on, and the battery would be fine. This sounds like it’s the cold, and not using it (to keep it warm) during the cold. Does she keep it out in her car at all?

EDIT: Both on my 5S and my 6S as well. I haven’t had my X long enough to know if it’s the same, but I assume it would be. Batteries don’t do well in the cold. Ask your car.

Went to the Apple store and they said, no, the battery is fine-it’s software related. Told us to back up to iTunes, reset the phone and then restore from backup. If it’s still having problems then we should just do a complete reset and set it up as a new phone.

Sounds like BS, but I hope they’re right.

Did she get a new battery while it was cheap for a whole year?

Yeah she did. They ran diagnostics and the battery seems fine. It’s at 92% and only has about 290 cycles so I tend to believe him that it’s not the battery. I guess we’ll give the back up and reset a chance.