My original battery quit working -- not only would not hold a charge but would not even work when plugged in.
The repair went great. Easy instructions.
Consider buying the P-5 Pentalobe and T-5 Torx screwdrivers and the spudger from IFIXIT. I couldn't find Pentalobe drivers at my local Ace hardware. It was OK, though, because I had ordered it from IFIXIT. They did have the T-5 Torx and for only like $1 less than on IFiXIT. The Spudger was very helpful in pushing in the new battery plug into the jack on the board. Also handy in prying the cover open and wedging the old battery out.