I switched from the iPhone 11 to the iPhone 17 pro max about two months ago, at first the battery was amazing and would last me two full days. The last few weeks it seems like it’s deteriorated and goes down fast. I charged it last night, closed all background apps and in the morning it had gone from 100% to 85% with no use…is this normal?! My iPhone 11 was better than that!
I just spoke with Apple Support about this exact issue. The technician acknowledged it’s likely a software issue.
He recommended a specific procedure to reinstall the update using a Mac, which is more thorough than a standard Over-The-Air (OTA) update:
Note: Use Command (⌘) to force a fresh download (whereas Option/Alt is for selecting local files).
I am performing this procedure right now as per the technician's recommendation. I will have to wait until tomorrow to see if this actually resolves the battery drain, but it’s a more reliable way to clear any 'runaway processes' or corrupted files from the initial update. Make sure to back up your device first.
I just spoke with Apple Support about this exact issue. The technician acknowledged it’s likely a software issue.
He recommended a specific procedure to reinstall the update using a Mac, which is more thorough than a standard Over-The-Air (OTA) update:
Note: Use Command (⌘) to force a fresh download (whereas Option/Alt is for selecting local files).
I am performing this procedure right now as per the technician's recommendation. I will have to wait until tomorrow to see if this actually resolves the battery drain, but it’s a more reliable way to clear any 'runaway processes' or corrupted files from the initial update. Make sure to back up your device first.
I am experiencing the exact same issue on my iPhone 14 Pro and Apple Watch after updating to build 23D127. My battery health is also fine, and before the update, I had 2 full days of battery life. Now I have massive standby drain. Since you are seeing this on a brand new iPhone 17 Pro Max, it clearly proves this is a major software bug in iOS 26.3 and not a hardware issue. Everyone on this forum telling us it's 'aging batteries' is wrong.
15% overnight is Normal. That's why you should charge it through the night, every night, to 100% with optimised charging activated.
I just spoke with Apple Support about this exact issue.
The issue is not charging overnight!
Oh okay thanks. Just that in the first two months it’d be on around 95% every morning and now it’s 85%. My iPhone 11 was also only ever down to about 95% on a morning
Yeah my battery health is normal and maximum capacity, it’s constantly going down even with out use!
iPhone 17 pro max battery deteriorating fast
