So I’ve had this issue before (a few months ago) although starting at lower percentages like 83%. Basically it just starts to at a certain percentage dramatically drop the charge current to unusable levels. Expected to be greeted with a fully charged tablet after lunch today and I found it with 90% charge (not enough) with charging current effectively being a super low trickle charge (this is NOT normal behavior). I’ve also had issues with the charge going up to 95%, sitting for a while there and then immediately jumping to 100%. Another issue is that, even though I try to keep my battery from being discharged too deeply, it sometimes starts dropping more rapidly at 25-ish percent and before I am done with my tasks and ready to plug it in, it has already dropped down quite a bit more. This is mainly a problem when I use lots of external peripherals that do take some power while doing intensive stuff on the tablet (current draw usually 2800-3400mA, sometimes up to 3950mA in extreme cases). It’s been working just fine for the most part until now aside from two occasions where the screen started flickering at 69% and 21%. I’m not sure, but the fact that until mid last year I didn’t know full discharging was bad possibly already set the fate of this battery. Is there any way to recondition this battery a little as it seems to have 9% capacity (according to Accubattery last time I checked the health meter), or at the very least make sure this stupid charging current issue that happens sometimes. The tablet in question is an SM-T825 Galaxy Tab S3 LTE, purchased in July 2017 if that matters. Cycle count is 287, battery still works decently but has the aforementioned issues intermittently.
Edit/Update: just checked and it is at 100%. This behavior is freaking strange.