The has been a lot of problems with the slow charging batteries. I found something that maybe of some help. Naturally I read this after I think I solved the problem. The article basically collaborates what I thought., just uses a different name.
I an using e/OS same issue here.
When I posted I was told charging port was dirty so I cleaned it with contact cleaner and a toothbrush. Same issue. The I was told that the battery had to be replaced, new batteries are almost non existent, so I did. Same issue.
There seems to be a pattern to this non charging and it looks like a cycle. A number of time my battery discharged and the charging time would be between 18 hours and 1 day and 10 hours. Instead to charging and waiting that long I let it discharge until the phone shuts down then plug the charger in. Every time I have done this the battery was back to full charge in around 2 hours.
After a dozen charging cycles then the long time cycle would restart.
I was wondering if there is something in the charging code that causes the slow recharge after so many recharges then the battery has to be re-calibrated.
Calibrating a Lithium Battery:
To calibrate your lithium-ion battery, fully discharge it until it turns off, then charge it uninterrupted until it reaches 100%. This process helps reset the internal gauge used by the operating system.
When I had this problem, a new bottom module cured it. I am pretty sure it was the USB socket in the phone that caused the problem in my case. I don’t dismiss your solution as it works for you but I don’t think slow charging is a one answer fits all thing.
What I posted worked for me. The best way is to trouble shoot it yourself or take it to someone who knows what they are doing. I wasted money and time on free advice. It cost me a new battery because people wrote the battery was the cause. Numerous charging cables because people wrote that was the problem. Cleaning the USB port a number of times because “that“ was the problem. One evening I went to charge the phone and the indicated charging time was 1 day and 12 hour. I left it unplugged and started looking for a Shiftphone or a Terracube to replace it. The phone shut down due to low battery when I plug it into a charger that was supposedly no good, using a cable that was supposedly no good. It went to full charge in about 2 hours. The next 10 or 15 charges took 2 -3 hours then the charging time started to get longer with each charge. Then it was back to full charge in 18 - 20 hours. Then start the cycle over. Discharge to phone until it shuts off, full charge in about 2 hours. And repeat to Ad nauseam.