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The last couple nights I've unplugged my phone around 2am (the joys of having an eight week old), and at 6:30am I'm still at 100%. I dropped to 99% around 9am.

Do not disturb is on, but everything else is enabled.
 
My iphone 5s would drain 10-15% per night... too much I thought. My Galaxy S5 was at least that too. The only phones recently I've had without an idle/overnight drain were the Sony Z1S and now my LG G3. The G3 will sit idle for soooooooooooo long and use next to no power.
 
iCloud syncing? Background refresh? Low cell signal? There are quite a few variables that could cause this.
iCloud backups only run when the phone is plugged in and connected to wifi. I typically get 4/5 dots of LTE in my home. I'll try turning off background App refresh and location services entirely, but there's been no indication so far that either are doing anything.
 
iCloud backups only run when the phone is plugged in and connected to wifi. I typically get 4/5 dots of LTE in my home. I'll try turning off background App refresh and location services entirely, but there's been no indication so far that either are doing anything.

Could I safely assume that you've seen this article: The Ultimate Guide to Solving iOS Battery Drain? It's the best I've read, and it's written by an ex-Genius Bar worker.

It's very well-written a no-nonsense. Here's point #1: Step 1: Disable Location and Background App Refresh for Facebook
 
Could I safely assume that you've seen this article: The Ultimate Guide to Solving iOS Battery Drain? It's the best I've read, and it's written by an ex-Genius Bar worker.

It's very well-written a no-nonsense. Here's point #1: Step 1: Disable Location and Background App Refresh for Facebook
Thanks for that. I actually don't even have Facebook installed, so that's not it.

Last night I completely disabled both background app refresh and location services for all apps at the system level; still dropped from 36% battery to 29% battery overnight on the phone while the iPad remained at 36% all night. LTE signal is 4/5 dots on the iPhone, so I don't believe it's a weak signal.

Any other suggestions before I try a clean install?
 
Phone received no push notifications last night, but battery still dropped 5% in 8 hours.

Same for me last night on my 6 Plus, 5% in 8 hours, which seems high. That would imply only 160 hours standby time, a far cry from Apple's stated 384 hours of standby. My phone is on wifi all night with good signal, and I have background refresh off for everything. Maybe you only get that kind of time in Airplane mode or something? Only thing I can think of is I have one email account set to push (iCloud mail), but I only get a couple emails overnight.
 
Same for me last night on my 6 Plus, 5% in 8 hours, which seems high. That would imply only 160 hours standby time, a far cry from Apple's stated 384 hours of standby.
That's the thing that gets me; specs for the iPhone 6 claim 250hrs of standby (and as you said 384 for the plus). At 1% battery loss per hour, that's only 100 hours - far less than half what Apple claims.

I know that iCloud backups will only run when the phone is plugged in and connected to Wifi, but does anyone know if the same is true for automatic App Store Downloads? There's no mention one way or the other in the Settings pane.
 
That's the thing that gets me; specs for the iPhone 6 claim 250hrs of standby (and as you said 384 for the plus). At 1% battery loss per hour, that's only 100 hours - far less than half what Apple claims.

I know that iCloud backups will only run when the phone is plugged in and connected to Wifi, but does anyone know if the same is true for automatic App Store Downloads? There's no mention one way or the other in the Settings pane.

I went from 15% drop my first two nights to 1% drop the past few nights. I believe the culprit was Automatic Downloads in the iTunes & App Store settings. I turned off the Updates.
 
I turn off the cell transmitter (put it in Airplane mode) then turn on Wi-Fi. I use my phone this way after about 9pm. Once in bed and not using it, it loses about 9 percent over 7 hours sleeping. No backing up. No app updates. Just WiFi standby use. Clearly something wrong.
 
Turned off all automatic downloads in the iTunes and App Store settings last night, battery still dropped 7% overnight. I'm running out of possible causes, here.
 
Last night my charger stopped at around 12 and when i woke up at 6:30 it was still at 100%
 
Maybe a gremlink uses your iphone in the night

Maybe someone is interested in what is in your iphone
 
I charge my phone almost every night. But on the nights that I leave my 6 Plus unplugged, I typically lose 0%-1% over six to eight hours. This is with no change to the settings I have it on during the day.
 
My 6 either stays the same (0%) or uses 1% on standby overnight (6-9 hours).

Same with my previous 5s.

same. I actually thought my battery was defective the first day because I took it off the charger and it was still at 100% 4 hours later with regular calling/web browsing.
 
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