After carrying Nexus phones for years I bought a Google Pixel in December 2016. That was just after the Pixel 2 was released, so the older Pixel was priced well and still offered great performance.
I was very pleased with the Pixel until quite recently. The OTA update to Android 9 (Pie) in August has been a huge step backward. Since that update the phone’s battery life has been dramatically reduced. Where it once lasted all day with my typical usage, it now lasts only about 7 hours with only light usage. Further, the phone is often noticeably warm to the touch.
Being the inquisitive sort, I’ve done some experiments to try and find out why this is happening. There are no rogue apps running. Or at least the OS reports no app using more that 2-3% of battery power.
I put the phone in Safe Mode for a day so only the factory installed apps would run. Battery life remained abysmal. That suggests that the problem is not caused by an app at all.
I’ve come to believe that I’ve identified the source of the problem. It’s related to the Wi-Fi. If I turn off the Wi-Fi the battery life is closer to what was experiencing running Oreo. Turn it back on and it plummets.