After updating to iOS 27 my iPhone 17 began draining battery. It has been 5 days and seems like more than indexing. I have taken every battery saving step I can find online and nothing has helped.
this morning it told me that using the NYTimes app for 3 min plus 3 min in the background had used 10%. The battery check tells me that it is at 99% health but probably won’t be for long if this keeps up. Is there a way to revert to 26 until Apple figures this out?
5 days is the minimum amount of time it takes for the background indexing to complete following an update. Make sure you are charging your phone all night, every night while it is connected to WiFi and using Optimized Charging.
If you have a VPN installed, remove it and don't just turn it off. The battery usage of a network connection using a VPN will be reported on the app using the network, not to the VPN that is installed.
No you cannot revert back to iOS 26, that release is no longer signed by Apple and cannot be installed on your device. That has always been the case shortly after an update where reverting has never been supported.
With previous updates 4 days was typical, but with iOS 27 there is much more indexing being done for Siri AI and Spotlight.
I have found when I go to Settings > Battery > View All Battery Usage, if I see a high amount of Home & Lock Screen usage that is a pretty good indicator of background process still being performed. Also on your daily graph shown at that page, any bars shown in light gray are the result of background activity. That graph does not show background activity specifically for the indexing though and includes all background activity that could also point to other app usage that is draining your battery.
Do you have any Meta apps? Those are usually seen on devices showing high battery usage. Testing without an app is easy by uninstalling it and compare your results. For Meta apps, you can sign into your account using a web browser in the meantime while comparing your battery usage without the app installed.
You can also post the screenshot you are seeing at Settings > Battery > View All Battery usage that shows both battery graphs along with the top 6 apps consuming your battery. If you see high usage on the bottom of the screen under Other Battery Usage include that as well. In the daily graph, it is best to select a day such as yesterday where the data listed will be for a full days data instead of just a partial day. If you are only at 5 days now after the update, it may be best to wait 2-3 more days and make sure you are charging all night, every night with the phone connected to WiFi.
How much data is on your iPhone? For example I have almost 300GB on an iPhone 18 Pro Max and indexing, syncing and optimizing took about 8 or 9 days. But I plug my device in at night, lock the screen and connect it to WiFi. This allows a lot of the heavy lifting to be done while you’re sleeping.,
Thank you, that is helpful. Everything I read said 4 days so I thought I was hitting a problem. Is there a way to see when the indexing is done? I read a couple of things but when I tried them I didn’t get an “indexing…” message
iOS 27 battery drain after 5 days
