I have a 2010 Snapper Pro 150. It has been great, but I have been having trouble with the battery drawing down between mowing our yard from week to week. I had battery checked and they said it was still good. I changed voltage regulator. It is actually putting up about 13.8 amps. It never fails we have to put battery charger on it and once battery is charged it cranks and runs fine, but a week later I will have to charge it again. Any help would be appreciat