So when I bought my UD Pulley from TR they reccomended buying a seperate AC pulley for better battery charging..

Now I'm finally going to put the AC back in and I have no idea which pulley to replace with the one I have....

 

A/C has nothing to do with the battery charging. They probably recommended you install an overdriven alternator pulley, which would spin the alternator faster for better charging at low rpm. It's kind of a case-by-case thing though, I didn't overdrive my alternator when I put my underdrive crank pulley on and have zero charging issues, even with the a/c & both rad fans running.