First ride - successful, but almost killed me

I put the kit on a Huffy Surfside Beach Cruiser. First time out, nothing. Checked the forum and read that the stock wire connectors are no good. Cut off the connectors and soldered the wires together. Boom. Starts right up. Having a great ride, until...
Rear hub comes loose, locks up, bending the rear axle bolt, the wheel seizing, I almost get thrown head first into the briar patch. Back to the drawing board. Think I'll transfer the kit over to a 15 speed ATB, no coaster brake.

Just out in the shed assessing the damage. I think what I'm going to do is take the wheels and the brakes off the ATB and put them on the cruiser. That seems the quickest out of this mess right now. Wish me luck.