I feel I'm having the same issue as OP, though it doesn't seem that the issue was ever resolved.
2 days ago, my touch-pad stopped charging.
My touchpad is running webOS 3.0.5, & dual boots into the most recent nightly of CM9.
Used the battery down to 20% and plugged her in. I came back later that evening, and found my battery "charging", but now at 6%.
I did a cursory search, and found a lot of threads that called out the 200A adapter and the original USB cable. My wife has a touchpad, which is still charging regularly, so I used her adapter and cable. This made no difference. Over two hours, the battery "charged" and held at 6%. I also attempted to use her touchstone for an hour or so, and no charge was added while the TP "charged".
Found a thread that mentioned the idea of trickle charging. I attempted that, by plugging the TP into my kindle set-up. This was unsuccessful, and knocked my battery level down to 4%.
I have tried charging with the TP off. This did nothing.
I have tried charging it while running CM9. This adds a little bit of pop to the battery, but nothing that ever gets above the double digits.
When in webOS, I have run Dr. Battery. It reports the battery still has 90% capacity. It shows that when using it on AC power I'm still running a -200 something mA loss (with screen dimmed, all radios off). I've tried doctoring; the doctor gave me a big middle finger, though, and told me to come back when I had 20% battery.
I read a few notes, from some really dated CM9 forums, that there were some android kids who were scared that android was susceptible to screwing up the touchpad's "charging circuit". I'm not savvy enough to know what that means, but I honestly doubt an issue like that would still be persistent in the latest nightlies...right?
Has anyone else, other than the OP - 2 years ago - had this issue? Any fix? Am I SOL?
Anyone wanna buy it for scrap & parts?