First check the S/G to see if it's making electricity or not, take the belt off of the S/G pulley, turn the key then short out the "F" terminal to ground with a jumper wire, the S/G should slow way down if it is making electricity.
If that proves to be good then run a jumper wire from the pos battery post to the "bat" terminal on the V/R if that doesn't make it charge then go here,
http://www.cubcadetman.com/content/i...tor-&Itemid=53
Authors disclaimer:
Please understand that I do not believe this information to be "all inclusive", I am sure some of the other folks here know a lot more about diagnosing a non charging Cub Cadet than I do, so by all means, listen to what they have to say.