Best way to preserve battery in backup phone

[sleze]

So here is the situation...I bought my wife and I X4s from Google Fi about a year ago and my wife has recently been complaining about her power button not working (though it still functions via the thumbprint). At first I thought it was her abusing the phone (like the last 3 she has destroyed) but because of her insistence that this time was different and the fact that this is a common failure mode of these phones (example 1; example 2), AND the fact that Google had a 1 day, 1/2 price sale on Pixel 3s, I got her one of those.

So now I have a backup phone that has a broken power button with a workaround. What is the best way to prolong the life of the battery in that phone? Let it power down and leave it idle for a year? Always keep it plugged into a low power USB power source?

PS - any easy way to get chop/chop->flashlight and swivel->camera on onto a Pixel?

 

[oz42]

Best way is to charge the battery to around 60% and then power off.
Leaving the battery alone for one year with a 1% or a 100% charge would definitely damage it.

 

[sleze]

That is consistent with other lithium ion battery management (non-cell phone) advise I have found in research and I am going to do it that way. The problem I encountered was that, I can't just power down (broken power button).

That being said, I did find the following using adb/fastboot:

To power down: adb shell reboot -p

This brings the X4 to a powered off state and when plugged in shows a recharge status. However, when you plug it in, it will NOT allow you to do anything without the power button.

To power up: hold volume down and plug into computer. This should bring you to the fastboot menu. On the computer type: fastboot continue That will bring you back in as normal.

 

[sleze]

Another update. Since it is now my backup phone, I am experimenting. I followed the below instructions to unlock the bootloader and root the phone and it essentially worked perfectly (instructions wise):

https://forum.xda-developers.com/moto-x4/how-to/guide-how-to-root-moto-x4-install-twrp-t3806460

Because my power button is broken, I had to modify the instructions. Instead of booting into TWRP after installing (which requires the use of a power button), I just pushed the twrp image again and then installed magisk.

Note that Motorola's unlock site was sort of down when I did it but there is a forum that Moto regularly checks if you run into problems which is here:

https://forums.lenovo.com/t5/MOTORO...-Unlock-Problems/td-p/3222809/highlight/false

 

[sleze]

And yet another update. After I rooted, I installed Custom Quick Settings and created a Reboot quick setting to replace the functionality lost with the power button. There is also a reboot into recovery option that should allow you to get into twrp.

Also, if your power button is broken, you need use the thumbprint as your unlock because otherwise, you won't be able to wake up the phone. I don't know if this works with the noNavigationBar setting but I don't want to risk it.

 

[oz42]

To power up: hold volume down and plug into computer. This should bring you to the fastboot menu. On the computer type: fastboot continue That will bring you back in as normal.

My phone's button is still not broken, so I did a

fastboot oem off-mode-charge disable

and now it powers up when I connect it to a charger.