iOS 15.2 Battery Drain

As posted in the 15.1 battery drain thread, some of the fixes that I found might help with 15.2 as well. I'm talking about drain that persists for more than the 1-3 days after an update while Spotlight is indexing. I had my iPhone 13 Pro Max and iPad Mini 6 BOTH draining enough to run dry in 20 hours of standby, and fixed it completely, so I'm still on 15.1 with no issues..

1) Turn off Apple News Widget on your Home Screen if you have it configured. I had seen that Apple News was using a lot of battery in "Settings > Battery" and I wasn't using it. Turning off background app refresh made no difference in battery use and drain in the background. Then I discovered the widget hiding on the screen to the left of the Home Screen that has my app icons, and turned it off. That reduced my drain from 5-7% per hour to only 3-5% per hour. I also turned off most of the other widgets except Calendar, Reminders, and Battery level for bluetooth accessories (watch, and AirPods).

• Turning off other widgets had no impact on battery drain.
• Turning off push mail had no impact to improve battery.
• Turning off Background app refresh had no impact on improving battery.
• BEFORE I REMOVED APPLE NEW WIDGET EVEN LOW POWER MODE DIDN'T SEEM TO IMPROVE DRAIN.
• ONLY AFTER I removed Apple News Widget did low power mode make a difference in drain, and in Low power mode I could get though a 16-18 hour day without plugging into power. But not till I did #2 below could I turn off low power mode.

2) I had my iPhone 13 Pro Max and iPad Mini 6 paired with my iMac and MacBook 16", and had "show this iPad/iPhone when connected with WiFi" turned on. I "Reset Network Settings" which broke this pairing, and COMPLETELY solved my battery drain issue. I was later able to plug my devices back into my iMac and pair/Trust them, but I made sure to turn OFF "show this iPad/iPhone when connected with WiFi" when I Trusted them, and the drain has not come back.

Apparently the WiFi network connection between iDevice and Macintosh computer maybe has the iDevice phoning home continuously in 15.1, even when you are not on the home, and this system resource is still draining the battery regardless of low power mode or not. But my best guess is that when the iDevice is NOT looking out for the computer constantly, with "show this device on wifi", then the drain goes away completely FOR ME. This might not be your problem.