Battery longevity, max/min charge level in Android

[Zarhan]

As I hopefully get the Astroslide soon-ish I'd like to be prepared to perhaps treat it's battery better than Cosmo's.

Does Android 11 come with any battery charge level settings built-in? Or are we still required to root the phone and use software like this https://play.google.com/store/apps/details?id=com.slash.batterychargelimit that may or may not work?

It's just that setting my EV to charge to max 80% every night is a trivial, built-in feature, and same goes for my Thinkpad laptop, do Android phones have any "elegant" options for setting the max battery charge level to 80% and making it not recharge until SoC has dropped below 40%? Or something like that...

[wovoja]

For this task to preserve the battery on all my Androides (incl. Gemini and Cosmo) since years I use the App
https://play.google.com/store/apps/details?id=com.digimastersolutions.battery4080.pro&hl=de&gl=US
You can set the under and upper values and set a signal. Switching on/off is not possible.

[Zarhan]

Yeah, I'm aware of those battery *monitoring* solutions, and I find having to use those rather...silly. I mean, why should the system need a human to yank the charging cable? Furthermore, in a proper setup the device can still be powered by the charger, it just does not shunt any more charge into the battery after reaching a specified limit. If I have to remove the charger manually after reaching the limit, it will also mean that the battery has to start de-charging instead of just leeching off the wall socket. Furthermore, I typically charge overnight, so getting an alarm beep after few hours into sleep is even more silly...

But ok, looks like this feature will require rooting the phone then.

[mikehg]

I've been reading a bit about this myself. It seems with certain kernel options you can bypass the battery entirely, letting it run on mains while the battery slowly self discharges down to a preset voltage, rather than yoyoing up and down running the device off the battery. That'll be the best option, I assume.

https://android.stackexchange.com/questions/223812/dont-charge-the-battery-but-use-connected-power-to-run-the-phone

There are hardware solutions you can buy too. One called the 'Chargie' sounds like it'd cover all use cases, but it's pretty expensive.

Apparently there are things called 'factory cables', which are bought or made (I think simply by shorting certain pins?) and should allow you to run the phone without charging it. Not a perfect solution (won't charge to a desired level then stop, obviously), but potentially useful for using the device for extended periods.

edit - upon further reading, I think the factory cables only work with specific phones, so no idea if that's an option.