iPhone 7 Plus losing a lot of charge when turned off

[EugW]

I have three phones not being used much right now after I upgraded: iPhone SE (original), iPhone 6s, and iPhone 7 Plus.

If I charge them to say 75% and leave them off for a couple of weeks, the SE and 6s still have lots of charge. However, the 7 Plus has way less. Maybe less than 20%. Battery health is 88% for the 7 Plus. For the SE and 6s they're at 92% and 93% respectively.

Have you guys and gals encountered similar behaviour?

 

[now i see it]

Yes it seems that iOS 14 is doing something even when the phone is turned off.
If the battery was removed from the phone, it would probably drop 5% in a year. I have other lithium ion batteries in other non Apple gear and they don’t discharge at all in storage.

Ok - you got me wondering about my iPhone 7 I put in storage in a drawer about 2 months ago. I stored it at 75% charge. I now took it out and tried to turn in on but it’s completely dead. Zero charge. Won’t boot up. iOS 14.8.
It’s charging now and eventually should boot up when it gets enough juice.

So yeah - iOS 14.8 hosed the iPhone as far as battery charge retention is concerned

Ok - now I checked my iPhone 5 in storage on iOS 10. It was stored at about 75% charge 3 months ago and now it’s at 65% - so that’s about normal.

 

[EugW]

Yes it seems that iOS 14 is doing something even when the phone is turned off.
If the battery was removed from the phone, it would probably drop 5% in a year. I have other lithium ion batteries in other non Apple gear and they don’t discharge at all in storage.

Ok - you got me wondering about my iPhone 7 I put in storage in a drawer about 2 months ago. I stored it at 75% charge. I now took it out and tried to turn in on but it’s completely dead. Zero charge. Won’t boot up. iOS 14.8.
It’s charging now and eventually should boot up when it gets enough juice.

So yeah - iOS 14.8 hosed the iPhone as far as battery charge retention is concerned

Ok - now I checked my iPhone 5 in storage on iOS 10. It was stored at about 75% charge 3 months ago and now it’s at 65% - so that’s about normal.

Hmm… However all my phones are on iOS 15. I only turned them on today to install 15.1. So it’s not the difference in OS. I suppose iOS 15 drains certain phones more though.

 

[now i see it]

Maybe it’s a hidden “feature” carried over from iOS 14 too.

 

[RobertM.Easley]

I have been using iPhone 7 Plus for like an year. I also noticed the same thing. Decrease in charging even when, it's switched off.
I think it's pretty normal, but if the decrease in the battery is too much. Then i guess, there is an issue. My iPhone 7 plus had some issues in charging IC. It was not giving need voltages. That's why I had high battery drainage when it was turned off.

In short, if the battery drainage is high while your iphone is off. You need to ask a repair shop to check if the voltages in ICs are alright.

 

[now i see it]

If the phone is still plugged into the charger but the charger is disconnected from power, there could be some backfeed going on between the phone & charger - current leaking back to the charger.

 

[EugW]

If the phone is still plugged into the charger but the charger is disconnected from power, there could be some backfeed going on between the phone & charger - current leaking back to the charger.

It’s unplugged