I was sent my 7plus to Switch service center for battery replacement after I bought my 12promax. It tooks 2 working days of waiting due to out of stock.

After I get my 7plus new battery replaced, the phone doesn't seems improvement on its battery life. I was thought that it was caused by the iOS 14.2. I reformat the phone then flash a fully clean iOS 14.2 again into my 7plus but the battery still drain out fast. I was thought that this issue may solve by upgrading to iOS 14.3. After I upgrade to iOS 14.3 at few days ago, the phone still doesn't seems have any improvement. After I upgrade to iOS 14.3, the battery level already dropped to 70%+, then I leave it for idling for 4 hours. After 4 hours, it was dropped to 40%+ left. So I recharge to phone back to 100%.

I was tried to reboot the phone and hope battery problem may fix. The battery drain quite fast and does not help much after replaced to new battery. This issue is mainly caused by iOS 14 but not the battery itself. My 7plus now is using a new battery with 100% battery health, the battery is still new since I was just newly replaced it at last week only.

When I watch Youtube video with the 7plus. Half hour will consume about 7~8%. If I leave it idle for 4 hours, the battery level will drop by 4~5%.