A dead battery causes all sorts of funky things in a small engine. PTO not engaging, or when engaged it causes the engine to run real slow, almost like its running out of gas. Those are the two I see most.
Not sure what motor is in the x500, but most of them small engines have a fuse somewhere, probably 20a, on the charging circuit going from motor to battery. So try to locate a fuse that may be blown and replace it.