01 XJ charging issue

Yep its me again.... my charging gauge is dropping out to zero but it isn't all the time. I just replaced the battery. Last night the gauge dropped to zero but when i started it up today everything was reading normal. Is this a straight up alternator problem or is it a battery cable issue? when i changed the battery i cleaned the cable clamps but did notice that the wire to the clamp was a little green. I am going change the negative cable but was wondering if anyone could tell me if it was the alternator?
:banghead:
thanks

You said that the charge guage was reading zero, What does the battery read when resting? It should be at least 11v. and around 13 or 14v when running. I would go ahead and replace the cables, they're cheap, and it sounds like the battery isnt getting charged or isn't holding a charge. You can also make sure the cables connecting the alternater are good etc. Make sure the cables are grounded too. Check the battery cables, and also you can see if there is anything draining the battery while everything is off by testing the fuses when the car is off. The only thing that should take a draw is the clock as far as I know.

Oh Yeah... ... DRIVE IT LIKE YOU STOLE IT!!!!!!!!!!