The first batteries on the 300's were undersized and tended to crap out quicker than expected... Try jumping it, and if it works replace with a higher capacity one.
Had the same problem when I bought my bike. If it didn't turn over on 1st or 2nd go had to jump start it. Battery seemed to take a charge fine but just kept happening. Turned out battery just wasn't strong enough for the bike. Put and HD one in and no problems since.
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