Sorry that those battery instructions didn't work out for you. I also had a similar problem with the battery not charging after 86 %, I didn't go through with removing the battery (couldn't find a small screwdriver) so I started testing other things out. I couldn't get a charge with the wall adapter nor the usb cable straight to computer. The light was amber, but there was no lightning bolt on the battery indicator to show that it was charging.
Well, when I turned off airplane mode, and tried to charge through the cpu, it worked! The lightning bolt shows on the battery indicator (and not just having an amber light). For some reason, it wouldn't charge with the wifi off. If that is your case, you might want to try it. After I charged it to 100% through the cpu, and used it for a few days, the wall charger also now works. Don't know if this is just luck?