Explanation:
This is a Samsung tablet from 2014, currently has LineageOS 18.1 (Android 11), the last it can get. Since it's unused I did a little experiment until I find someone who will use it. Today I have found so here is the post.
After charging it to 100%, I disabled Wi-Fi connection, put it on battery saving mode and it's been on for more than 2 months. Battery is still in good condition after all these years I guess. :)
Wow, 2 months? How big is the battery!?
Looks like the current version of Accubattery works on Android 7!
If you install it and then do a full charge cycle (15%-100%) it can determine battery health by how much power is required for that charge cycle.
It's not perfect, but I've found it pretty effective at predicting my run times over the last 10 years/half a dozen different phones.
I'd even upgrade this from mildly interesting to interesting!