Thanks for checking on that. That's not a good sign then - it sounds like a battery issue as you say. I haven't really come across this before, but maybe being left to run flat for those ~3 years did cause the battery issues.
You could try leaving it on charge for several days, just in case there's a chance it'll recover a bit more?
Update! That seems to have worked.
Left on charge for 4 days (2 days turned off,then 2 turned on).
Took off charge Saturday morning and set up and been using since….60 hours in and battery still at 85%.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Thanks for checking on that. That's not a good sign then - it sounds like a battery issue as you say. I haven't really come across this before, but maybe being left to run flat for those ~3 years did cause the battery issues.
You could try leaving it on charge for several days, just in case there's a chance it'll recover a bit more?