If it is on the charger now, don't leave it on too long. Feel the outer side of the case and if it is getting hot, remove the charger. It should be only warm. Many a good battery is ruined by over charging. If you have a trickle charger, that is best. My best guess is that there is a bad cell in the battery. If you have a car with a battery of the same size, switch it and see if the problem goes away. If it doesn't, then it is in the tractor. Another trick to try is to remove the positive terminal and then touch it to the battery with everything off. If you get a spark, that indicates that the is something drawing current. You can also use a test light between the battery and the terminal to see if the light comes on. If it does, then there is a draw on the battery. If it doesn't, then there is no draw. Unlike a car, that has the computer, clock, radio, etc. constantly drawing current even though the ignition is off, tractors don't draw any current when the key is off.. Good luck with this and if I can be of any other assistance, please post or PM me...