Do a traffic dump and check how many thousands of requests its handling for all your personal data from every app installed.

It's one of the reasons running standard Linux, or even de-Googled Android, on a normal Android device can absolutely tank your battery life. Waking up the radio is expensive, and packets coming in at random moments means the work put into power saving scheduling goes down the drain.

Not necessarily. About eight hours ago I was having trouble with the GPS on my main phone (I cleared GNSS on GPStest app and it wasn't refreshing fast enough), so I found another in my assortment of phones that was still running and had some charge left in it and used it (it also had GPStest installed)—and I'm using it now to post this comment.

It's a Huawei GR5 Honor from 2017 with original battery that I've de-Googled, and when I picked it up earlier the battery indicated 22℅ remaining which surprised me because I've not used it for some weeks.

When I read your comment I thought I'd ckeck the battery and phone usage logs and I'm now even more surprised. The phone was last used on July 19 (24 days ago) and the battery drain graph shows a very gentle and almost perfectly linear decline from then (until I put it on change and started using it).

Moreover, it estimates remaining battery life in standard/default power mode at 8 days 23 hours (but it's since been on change). Note: the phone was set to standard power mode during those past 24 days. If I switched to 'Power Saving' mode the estimate is 11 days 16 hours, and in 'Ultra Save' its estimate is nearly 33 days (778 hours 44 mins).

Incidentally, the phone has 346 apps installed.

It's amazing what battery life one can achieve when one stops both Gapps and user-installed apps yapping back to Google-Central.

Most people use some kind of app that receives push updates from the internet onto their smartphones, whether that's Facebook or WhatsApp. If you can live without those apps then you'll have a much better time, because the WiFi can actually turn itself off completely and the phone modem can fall back to a state as passive as possible.

You don't need to de-Google your phone for this effect. Just disable all internet access (WiFi off/disconnected, cellular data off) and your phone can last a day longer. Works great for devices repurposed as navigation systems!

True, that's my experience too. As mentioned, I've well over a dozen unmodified and rooted Android phones and some of these have been repurposed including for navigation, remote control of equipment etc.

I'm not a typical user, no social media, no Google accounts, no cloud storage and such, so for phones that aren't rooted Gapps are either disabled or where possible removed, similarly, any running services that I'm not using are stopped (if possible). On rooted phones apps only run when I'm using them, WiFi/SIMs are disabled and or airplane mode is on when the phone is not in use, also no background data is allowed etc. so I expect my phones to last for days without recharging.

What surprised me about this Huawei is that it is six years old and the battery has been abused—left charging at 100% for days on end—yet it still managed 24 days on standby in normal power mode. No doubt it would have lasted a full month if I hadn't used it today.