what's a reliable way to determine my device's battery health? something like Coconutbattery for macOS - charge cycles, health, factory/remaining mAh, etc...
tried CPU-Z, says health is "Good". gee, thanks... out of what, "Excellent" through "Shit" or what?
backstory, I got a Samsung Tab S6 used, wiped it and installed LineageOS 20 and I'm using for a couple of months. the battery kinda sucks. granted, I have like 3-4 hours SOT/day but a 7000 mAh battery should last a couple of days; pure guesstimation, I had an iPad some years ago and that thing lasted for eons.
if I leave it overnight with 10ish% battery remaining and battery saver on, it's dead by morning. that sort of drain can't be normal? on the other hand, I don't have google services so every app has its own running service - syncthing, KDE Connect, Allcast, Jellyfin Player, etc.
there's the stuff I can read from /sys/class/power_supply/battery/ but nothing useful in there; like charge_full and charge_full_design are the same (70400) and other promising sounding items are unset or nonsensical.
tried the same on my Redmi phone w/LOS, completely different files there and equally useless.
I don't wanna go through sourcing the battery, prying the thing open and replacing it, only to find out that's how it's supposed to work. any ideas?
Try Accubattery, it's pretty good for the health check of the battery.
tried it, that's the opposite of what I need. that app guesses what's going on with the battery, based on prolonged usage patterns. I need something that talks to the battery controller and gives me numbers I can use.
It can do a health check, just requires 1 or 2 full discharge/recharge cycles.
It measures current consumed during the charges and compares that to the battery specs.
Over the years I've found it pretty accurate. I keep multiple phones of the same type with the exact same OS/app build out, and can see the difference in battery health between old/new, and see it reflected in battery life when using either one.
I keep phones forever, and run AB on them once or twice a year, and it consistently shows their health dropping. I lose about 7-10% health per year, and that's reflected in reduced battery life during a day.
One phone is down to about 40%, and even with Lineage you can tell. It can run for a couple hours before needing a charge, while the 83% health phone goes most of a day. Again, same hardware, same OS, same apps, same usage.
Yeah you're right, it guess the battery health based on prolonged usage. I'm not sure what you are looking for exists in stock Android ROM. It's very possible that info is restricted to the system, so apps cannot access it.
Let us know if you find something, I would be very interested.