My 83 280zx had a bad alternator so I canged it and everything was fine for a few days and then the volts started getting lower and lower. The battery would never get low enough to die but at night with all the bels and whistles on they would go down to around 10. I changed my battery and the battery cables and it seemed to help some but the alternator still isnt putting out what it should. Is there some relay I should check out or is this a common problem. I'd like to check the simple things first before I pull the alternator and have it tested. Any input would be greatly appreciated. Also why does the NEG (-) battery cable ground at the starter and below the battery tray.

 

Just curious where did you buy your alternator? I have heard that Checker sells crappy electrical parts. I think you are getting bad alternators. Also check your positive battery cable. I had trouble with my '81 with a loose wire inside a thick black covering. It would cut the power, and I would have nothing. I don't really know why Neg battery cable ground at the starter. That is puzzling.

 

Thanks for the feed back but my problem was a loose belt. I put on a brand new one and it stretched way more than I thought it would.