It's probably a short. I've had to have 4 new batteries changed out for same reasons. Take it to the shop. You'll end up spending less in the long run if you're not real knowledgeable in area of mechanics.
Obviously, you're doing something right if he/she is still there. Keep doing what you're doing. Just see how long the little guy or girl sticks around. It may be using that big fruit bowl to dunk himself in every now and then. But use gloves if you're going to pick it up. I've heard people can...