I have a new troy bilt pony, it's been used twice after the second time I was going to put it in the shed and when I turned the key nothing happened, I thought the keys was left on. I pushed it in the shed and the next week before I used it I charged the battery, when I put the charger on the battery it registerd 80%, I charged it to 100%. Still nothing, I've checked all the connections and made sure the parking break swithch was engaging and the blade is up... need help please