Even with an inactive 5G connection and disabled background processes
As 9to5mac reports, more and more users find that the iPhone 12 battery drains quickly in standby mode, even when the 5G connection is inactive with a simple Wi-Fi connection.
User Master26A on the Apple forum raised the iPhone 12 Pro’s fast battery drain in standby mode. Shortly after purchasing the iPhone 12 Pro at the end of October, measurements showed that the battery was draining about 4% per hour in standby mode.
Since then, over 1000 people on the same thread have stated that they face the same issue. Many lose 20 to 40% of their battery power overnight, and many have tried turning off 5G background apps, but to no avail. The battery settings section does not tell you what causes the battery to drain quickly. Even when Low Power Mode is on, the battery will discharge at approximately the same rate.
One user reported that Apple Service Center performed battery diagnostics, which showed no problems. This led to the idea that we are talking about a software bug in iOS.
Today I spoke with Apple support. They ran a diagnosis and said everything was fine. I am guessing there is a software issue that is causing the battery to drain. Hopefully, they will solve it soon. Closing all apps, disabling background app updates, disabling Bluetooth, and ultimately losing 40% battery overnight are not normal.
Also, messages about fast discharge actively appear on Reddit and other forums.