Weird battery level graph

[zorinlynx]

My mom was complaining that her phone battery was lower than it should be, and when I checked the graph I saw this. It looks like the battery suddenly jumped from just over 50% to around 25% around midnight for no apparent reason, and stayed exactly there for many hours. She didn't use her phone around that time at all.

Is this a sign that the battery is failing, or just a bug in iOS? Anyone else seen this before?

It's a slightly over four year old iPhone 6.

 

[Blue Hawk]

This only happens when the battery health isn’t good anymore I think.

 

[aakshey]

Battery has failed.

 

[zorinlynx]

Ugh, that'd be pretty bad timing since the $29 replacements are no more.

Though her phone is working fine at the moment. She's a pretty light user.

 

[C DM]

Ugh, that'd be pretty bad timing since the $29 replacements are no more.

Though her phone is working fine at the moment. She's a pretty light user.

I think they are at $49 now, which isn't too bad.

 

[aakshey]

I think they are at $49 now, which isn't too bad.

But they won't replace unless the graph shows 79% or lower.

 

[C DM]

But they won't replace unless the graph shows 79% or lower.

Potentially. Hard to say how strong of a comeback that part of it all has made at this point.

 

[Blue Hawk]

But they won't replace unless the graph shows 79% or lower.

They do. My dads iPhone showed 98% which was wrong. And they have changed it a year later for free.

 

[k0bayashi]

This looks like a battery failure.

 

[aakshey]

They do. My dads iPhone showed 98% which was wrong. And they have changed it a year later for free.

They only did from 1st Jan 2018 to 31st Dec 2018.

 

[now i see it]

It's not battery failure, it's the "digital battery level gauge" out of calibration.

Run the phone down until it almost shuts off, then charge it all the way back up to 100% without using it - use the standard slow/tiny apple charger. Not a fast charger.

Do that again one more time and the battery level meter should re-calibrate.
But don't make it a habit of running the battery down that low in the future. It's hard on it.

 

[luismedina]

I had the same during new year hoildays, I was in a place completely out of cell signal, phone in airplane mode all the time, and it went from 80% to 65% overnight, showing the same gap in the graph, my battery health is currently at 92%

 

[doxielover]

I had the same during new year hoildays, I was in a place completely out of cell signal, phone in airplane mode all the time, and it went from 80% to 65% overnight, showing the same gap in the graph, my battery health is currently at 92%

I almost always have my 6s plus on low power mode does this mess up the calibration? How come most websites say when you calibrate use the battery until the phone shuts off.

 

[chekz0414]

They only did from 1st Jan 2018 to 31st Dec 2018.

No, they’ll replace the battery as per customer request even if it’s not 79% for $49 or $69 which is the out of warranty cost.

 

[C DM]

No, they’ll replace the battery as per customer request even if it’s not 79% for $49 or $69 which is the out of warranty cost.

Now that the replacement program from last year is over, they haven't gone back to the established requirements for replacement?