Try cleaning around the center post. Use a thin 1 ply paper towel or tissue and a Drinking Straw. It should fit into that circular valley. Mine had all sorts of scrunge and fungue in there.
Any foreign matter might cause a voltage leak, and the battery's circuitry might perceive this as a short. (It is a short, but a small one, a short short?) There always seems to be something in there, and it gets wet from drops out of the center post. (condensed vapor, maybe juice getting around the wick...)
Then do the "5 quick presses" to shut it off, then try a charge. I had the 15 blinks, and i did the above, and now it's all good...