'93 Prelude won't charge any power, the car is just sucking juice straight from the battery. I got a brand new alternator from Benett. When they put it on the tester it says that its good but when i put it on my car and test it, it says its not charging power.

The car starts up fine but after a couple minutes it seems like the car is losing electricity and the dashboard seems to get dim and the gauges don't work. I have a good battery, a good starter and I just changed the main relay recently and all the fuses are good.

Has anybody had this problem before? Please Help. Could it be something wrong with the wiring or one of the relays, other than the main relay which I changed.