Yes it supposed to be more battery efficient than the 865 but it isn't , at least for now. maybe they will tweak it in next few months. we will see. But you can do some tweaks also and you should get improvement. I see some people complaining about chrome using a lot of battery so I would uninstall it for the start and use some other browser , I can recommend kiwi with built in ad blocker and dark theme and is super light. But there's many other. Also today I was experimenting with dynamic wallpapers and I saw significant battery drain which was very noticeable so I just put black background. I never went to battery to follow what's going on , my device easily go through the day with normal use. I would say from 7 to 23 my battery goes from 100% to 10 - 30% depending on the use. For me I am very satisfied with the battery life.
MIUI 12.5 EU 21.3.17
For all the people complaining about battery life I got 12+ hours of SOT today !
I have done some battery testing today after applying some more tweaks to the device and I got really good results. Note that it is a rainy day here today and I am on auto brightness.
AI image engine is turned all off. But it is still on 120Hz and WQHD.
And I was using device mostly for watching movies, videos from YouTube, Netflix and some 4k movie I had on the device.
Some of the tweaks that I applied I found here: https://www.facebook.com/groups/XiaomiDeutschland/permalink/1126756584403672
Thanks @qvert for posting this.
PS choose your tweaks wisely!
And an advice on how to have a long healthy life for your battery:
Charge your phone when it gets down to 10% - 20% up to 80% - 90%
Use a smaller wattage charger , I use 5w as it doesn't heat up the battery at all. Only use fast charging when you are in need.
Really disappointed of the battery life. Wasn't the 888 supposed to be more battery efficient than the 865?
Light usage, not even 6h of SOT with 13% left. With indoor use (low brightness, wifi) , 120hz FHD+.
Compared to my OnePlus 8T, i can get slightly more than 7h of SOT...
I think that is the problem, try a clean install (install the apps manually). For me solved the problem.
Before the clean install I had to charge the phone 2 times during the day (with about 3-4h of screen)