I have a XT722FE lawn mower equipped with key start switch. I have just purchased it, and I let it charge for 24 hours before using it. However, when I went to crank the mower up using the key, it did not crank or even make a noise. I was holding the Operator Presence Control Bar down and everything. After trying a couple more times, I just cranked it manually and it started perfectly. I am charging the battery box again just in case. Does anybody know what might be wrong?