I'm suffering from excessive battery drains on Note 8, Nougat 7.1.1. The battery drain is excessive when on idle mode/when the phone is asleep. I have installed BetterBatteryStats (gave it all permissions) and tested with different settings for a couple days.
I strongly believe the issue is with my wifi.
- Day 1: I kept wifi on, turned off "adaptive wifi" and "wifi power saving mode" and set "keep wifi on during sleep" to always. Battery drain was very excessive at home. In BBS, wlan_rx_wake and powermanagerservice.wakelocks were very high and phone didn't doze much. When I left home and went to the library and was connected to my school's wifi, the phone dozed, and the two wakelocks mentioned didn't occur any more. In fact, from the screenshot you can see the two flat regions are those when I was at the library, and the downhill regions are when I was home.
- Day 2: I kept wifi on, turned on "adaptive wifi" and "wifi power saving mode" and set "keep wifi on during sleep" to never. No change. The results were just like day 1. Excessive wakelocks and battery drain. In fact, funny enough, the wakelocks occurred more often as if "wifi power saving mode" was doing the opposite of what it was supposed to.
- Day 3: I turned off wifi completely, and was on cellular the whole time. Battery performance was amazing. Lost 5% over 10 hours, and I actually used the phone during this time. I made calls, surfed the web and texted. Additionally, the are no excessive wakelocks, and the battery plot is nearly flat the whole time.
In conclusion, I am really confused. At home, wifi kills my battery. At school, wifi doesn't do anything weird. It makes me feel like this is more than just some setting on the phone or some bug with Nougat. Maybe some networking issues with my wifi at home? At any rate, I seem to have found the problem. But I was hoping I could get some insight as to why this is happening. Additionally, I'm wondering if there is a fix, because I would like to use wifi instead of cellular the whole time.
I was at home, I had wifi turned off, and during this time I experienced great battery life (~4-5% every 12-14 hours). Then, I turned on wifi just to test things, and the battery life noticeably got worse. I'm talking ~1% drain every hour. I turned it back off.
For those wondering, I experience wifi-related battery drain even if Wifi-Calling is off, so it's not that. Also, I have factory reset many many times so that is not a solution either.