[OnePlus 7 Pro ROMs, Kernels, Recoveries, & Other D] theslam08:
The only real way (and best way) to tell what is going on with battery drain is to measure it using an app like AccuBattery. Otherwise, there is no way to really know if some app is causing the phone to not deep sleep.

[According to AccuBattery] I can say I usually get around 4.5hr of screen on time. With use throughout the day, I can maybe get around 15-20hr of battery life depending on usage for that day (I don't game and primarily use the phone & text with light web browsing with screen brightness at 60%). AccuBattery says I have a 3200mAh battery capacity (health) remaining.

But I did a test just for some of you to compare and see it most likely isn't the ROM's fault, it is probably something rouge that you have installed.

I primarily used my other phone during this time so as to not skew it much (if any at all). I'll attach the screenshot.

Some background info:

-I only have data & WiFi on. No bluetooth or NFC

-I do not have rouge-potential apps like FB, IG, Twitter or TikTok installed

-I am using GApps

-I am not rooted

-I am not using the "always on display" feature

-I do have lift-to-wake and ambient display enabled (so it does light up for a few seconds when a notification comes in). And I did receive many notifications during this test.

-I do not have "network optimization" (or whatever it's called where it delays notifications and such) enabled.

The screenshot will show (to help break it down for you):

-It used a total of 14% in 13hr 47m. That is like 1%/hr.

-It stayed in deep sleep for 93% of the time that the screen was off (12.5hrs out of 13h and 26m). It used 9.2% battery while in deep sleep and 1.4% battery not in deep sleep (adding to 10.6% battery used during screen off time).

-I left the screen off for a total of 13h 26m out of 13h 47m.

-Screen on used 3.4% in 20 min

-10.6+3.4=14% (total screen off time + total screen on time battery usage)

With these stats, if I were to not use the phone, keep the screen off (and use it just for notifications), I could potentially get like 80-100hr of battery life (1%/hr, 100hr=100%). Now obviously phones are meant to be used. But I'm just pointing out the fact that, if you have the correct setup, no rouge (battery draining like running in the background, keeping the phone out of deep sleep) apps, the battery life is perfect on this ROM.

If you're getting 5%/hr battery drain overnight (while the phone should be in 'deep sleep' mode) then the phone is not going into deep sleep like it should be. Something isn't right - that is not normal. I used 422mAh in 13h 26m. 422 out of 3200. I can't really see it ever getting any better than that (except in airplane mode). Esp for a 3-4yr old phone.

Now while you're using your phone, that is a different story. Everyone's battery life will be different. This is very highly dependent on: your screen brightness, if you have BT and/or NFC enabled, how you use your phone - if it is to game (high battery drainer), talk on the phone a lot (pretty high of a battery drainer) or if you just use it to message people (not a high battery drainer). Also, battery capacity (life) left.

In the end, you must use a battery measuring app like AccuBattery to get the best idea of what is going on.