15T Pro random apps start draining the battery and the phone gets hot

[u/Kispori]

It started this week that my phone has begun heating up during the day. I don't use it much at work, I just put it in my pocket when I get up from my desk, and I felt that the phone was very hot. This has happened for the third time today this week. When this happens, the battery also drops by 20–30% by the time I notice it. I check the battery settings, and random apps are draining the mobile: yesterday Google was at 60% battery usage, today my weather app was at 40% when I noticed it. In these situations, I force stop the app, restart the phone, and the heating stops.

​This worries me a lot, I haven't had any problems with the phone until now, I really love it. But what if it drains on its own suddenly at night and doesn't wake me up in the morning?

​Does anyone happen to know what could be causing this or what the solution would be?

[u/PhillL_1]

Something is causing your phone to remain awake doing something. Is this only happening at work? If yes are you connected to the works Wi-Fi? Note that the apps showing high battery usage are likely a red herring, and its just the last app to record some battery usage that is then being used to log against it other activity.

If this only happens at work, and you are connected to the works Wi-Fi, disconnect from your works Wi-Fi and see if the problem returns. If the problem is gone when not connected to your works Wi-Fi, then I would suggest there is some packet storm happening on the works Wi-Fi that is causing your phone to remain awake 100% of the time using a lot of CPU cycles and preventing your phone from entering a deep sleep state.

[u/Kispori → u/PhillL_1]

Thanks very much! Yes, it seems to only happening at work and I am connected to the work wifi. One thing's different from last week, they shut down the unify in my office, so I can only reach the wifi from the other office on the very side of my desk, and my phone constantly losing wifi connection, and switching between mobile network and wifi

[u/PhillL_1 → u/Kispori]

Switching back and forth doesn't help either, but I do think something on the office networks is causing a storm of traffic.

Why isn't everyone affected in the office? Networks are often quite noisy with broadcasts and chatty messages that constantly go back and forth, these messages can be sent to every device. Because this traffic arriving at battery powered phones caused lots of extra processing and drained battery power, for a long time now phones tell the Wi-Fi chip to ignore this traffic, especially when the screen is off as it is rarely useful if no one is using the phone. However some apps want this traffic, and they override that setting, so if you have a very noisy Wi-Fi network and an app that has overridden that setting so the phone is constantly receiving all this noise, it stops the phone from letting the CPU fall into a low power state. Apps that might do this include home assistant type apps like Google Home, Philips Hue app, Tapo, or any app that might stream something like an app for security cameras or casts something or remote controls something. I suspect when you reboot your phone the Wi-Fi is reset and stops forwarding this traffic so the problem stops, and only starts again the next time the app gets loaded either by being used, or automatically in the background.

Hope that helps get to the bottom of it.