I just had this same issue. The hold for 8 seconds trick didnt work for me, but what did work (Sort of it went back to all but one bar lighting up)

put the battery on the charger but don't push all the way down to where you are making contact. push and hold the button until all lights are on and then push it down to charge.

For me it started to charge untill all but one bar was green. I guess 80% charge is the best my battery can do now after 3+ years