well usually going to charge less with the alternator now turning slower, but if it doesn't charge at all did you impact the pulley onto the alternator?
Charge your battery and put your stock pulley's back on. The underdrive pulley's don't make sense for street driving, less alternator charging, less water pump circulation. All for what, 1 horsepower more power?
Swap on an Overdrive alt pulley. That should take care of the charging issues.
As for cooling issues, if your cooling system is in great shape, you shouldn't notice a difference at all. If you do notice it runs hotter, than something in your system is in rough shape.
I put them on my car, with an OD alt pulley (1 7/8" dia) and it was a definite SOTP improvement with zero charging or cooling effects.
Charge your battery and put your stock pulley's back on. The underdrive pulley's don't make sense for street driving, less alternator charging, less water pump circulation. All for what, 1 horsepower more power?