Charging problems, help!

HI!
Ive got a 90 4c sw dt. had charging problems with it ever since we went to tixover. had the battery checked at that was fine but the alternator wasnt charging. i fitted a new alternator and took it for a drive.
when i put the lights on at tick over, the battery gauge went down quite a bit. then while i was driving along with them on it seemed to sit at half on the guage quite happily, but then! when i pulled up to lights or a roundabout it went down again!
finally when i got home, lights still on, it sat at half fine, then when i revved it went up! the same happened with the lights off.
this is my first landy so any help would be great!

thanks, chris

Check belt tightness and give all electrical connections a clean on the alty inc engine earths etc that'll give you something to do .

It's a fairly crude voltmeter and gives a guide to the charge/ discharge state of the battery. As far as I know you're probably OK if the needle isn't in the red when you're driving.

Cool I'll give all that a go tomorrow, thanks for the advice.