iOS 16.0.2 weird battery drain from Mail and Calendar apps

Hi,

I had the same issue, but only with the Mail app background activity (no issues with the Calendar app). The first thing I thought about was turning off the Background App Refresh for this app, however, I failed since the Mail app is not on that list of apps. Next, I followed the recommendation above and tried to disable syncing with iCloud, but again, I couldn't locate the app on the "Apps using iCloud" list. I only found the iCloud Mail feature that already was disabled.

Finally, I managed to resolve this issue by disabling the Fetch New Data option:

navigate to "iOS Settings > Mail > Accounts > Fetch New Data" and turn off the Push switch.

I also set the FETCH frequency to "Manually" on the same screen at the bottom. It worked and the next day there was no activity from the Mail app in the battery usage stats.

I believe the same settings can be applied to the Calendar app.

Greetings andreih8017, 

Especially after setting up a new device, it can be expected to have some some apps running as data syncs. Do you use any other accounts with the Mail and Calendar apps such as iCloud? You can verify that in Settings > your name > iCloud. If either of those options are enabled for syncing there, go ahead and toggle them off for the moment. Please do not sign out of your iCloud account though. Then, restart your iPhone. 

At that point, after the restart, let’s give your iPhone a couple hours. Are you noticing a change in the usage from those apps? They will show as ‘Recently Deleted’ since they aren’t installed anymore, as opposed to showing their app names. 

Thanks. 

update: i‘ve deleted any account from ios mail.app, set every of the beforementioned option and recharched the ipad air. while battery status went down from 100 to 17% percent the night before, i still had 100% this time. so it seems obviously to me that mail.app is causing the battery drain on my 5th gen. ipad - and (!) the problem ist related to ios16 version of mail.app

same here on a more or less brand new ipad air after update to ios16 - battery status went down from 100% to 17% within a period of 16 hours - where 41 minutes the ipad was used and in sleep mode for the rest of the time.

i do not remember having any similar issues while using ios15. when used acvtivley - e.g. writing this message - battery status is decreasing at a rate of aprox. 1% per minute - which is far more than it used to be and would result in a terribly low overall time of use - and thats far from the „Up to 10 hours of surfing the web on Wi‐Fi or watching video“ on apple‘s web site !!!

This is happening to me as well. Battery usage is showing 45% from the mail app and I only look at my mail a couple of times a day. I’ve had to charge my phone twice a day since installing 16. I was hoping the latest update would solve it, but it didn’t. I’m running 16.1.1, now.

Fetch is off. Push notifications are off.

A few days ago I updated from iOS 15 to 16.1.1 and now I'm experiencing the exact same issue. Mail app is consuming a lot of battery with background tasks, battery goes form 80% to 20% overnight.

I tried to disable fetch and push notifications but that didn't help. Doing a web search there are a few people affected by this exact problem but so far I couldn't find a solution that works. This is super frustrating and I wish I could go back to iOS 15

my post was deleted again - any kind of posts referring to any version that is not yet released are deleted by an AI algorithm oviously ... even if they cover a solution for an existing problem like the one discussed here.

my suggestion: switch over to the "not yet released version" which is under development and currently tested by users ... 16.x (where x = t.w.o) - not really a solution but a workaround

… by the way: iOS Settings > Mail > Accounts > Fetch New Data

was off the whole time. and according to the battery-info the only app that is consuming energy is mail.app in background-mode