Problem with the charging system...

[70cst10]

I've just about given up here.. My blazer has been driving me nuts lately. I've had to disconnect the battery to keep it from draining overnight. It hasn't been charging the battery much (if at all) either, but it will run fine without the battery hooked up. I've noticed that when I connect the battery, it sounds like the contacts in the voltage regulator are closing. It doesn't matter if the ignition is on or off. There is a loud click coming from the reg itself. I've replaced the voltage regulator with no improvement. The new one does the same thing. Could my problem be in the guage itself? What else is there? The battery is brand new. I just replaced it last weekend. I'd appreciate any help I can get here!!!

Milan