Does anyone else have this problem? It doesn't always happen at 27% and with no apps running, it's just baffling.

Must be part of the charm of having an Apple product.

Your battery needs to be replaced. What you're describing is a pretty common Li-ion failure mode.

We are fairly certain the universe is finally rejecting apple products.

Same thing happens with my mom's Pixel...but hers can be at 100% when it powers down.

My guess is bad battery or it crashed.

what iphone?

If you follow the rest of the internet, this behavior falls under the "normal" category. Anymore, you should feel lucky your face or house has not burned down....yet.

Apple has issued a battery replacement a couple of weeks ago. If your iPhone is out of warranty, the cost is $29.00 to replace the battery.

[Link: support.apple.com]

KOT

My wife is going through the same thing right now with her iphone 6...It's the battery thing that they're getting sued over.

$29 like others have said...Good luck getting an appointment in the store...and when you do get an appointment, hopefully they'll actually have the battery in stock..

Open the back of your phone and replace the battery.

And people still think Apple has nothing todo with this to get you into a new phone.

It’s been unconfirmed but widely speculated that your two year old + phone slows down and then your battery magically fails. I think we have all experienced it. And it’s not just iPhones it’s everything.

It’s planned obsolescence with the excuse “hey apps have gotten so advanced in two years that your phone is a paperweight”

This is not magic...its science....Li-ion batteries have only so many times that they can recharge...Apple made the monumental mistake of trying to have the software manage around this by doing some advanced power management....without telling anyone....

Also, as the battery nears EOL, the runtime from fully charged decreases and the battery's internal impedance rises -- limiting the maximum current draw. In this case when the processor power draw peaks, battery voltage collapses and the processor crashes. Adding a large capacitor could help ride across these peaks, but Apple did not want to commit the physical space necessary.

Properly managed from a PR standpoint, this power saving software (optional) patch could have been a winner for Apple.

But yet in many years past, I have had many different Li-ion batteries last me 5-6 years before performance fell off sharply.

So why is it modern Li-ion batteries seem to only get 2 years (about) before this happens to them?
Seems more like a dirty manufacturing technique that the companies have figured out.
But so many people refuse to believe the dirty tricks manufacture do, to make themselves more profit & money.

Back to the OP...

What phone and what version of iOS? The issue you are describing was a widespread bug about a year ago. A subsequent iOS update fixed it.

My Festool batteries have been the best batteries I have ever had. I’ve had my drill since 2011 and the batteries have been charged hundreds of times, lives basically outside in my truck during the hot and cold cycles and they haven’t lost an ounce of their ability. They are lithium batteries. Either size is a factor or there is something else going on.