First a big thank you to Shazaam!; the voltmeter arrived yesterday, although I only spoke to them on the phone on Thursday. Fitted it, and it showed up the problem straightaway!
Wasdn't quite the same problem that Shazaam! had, (although he'd have a different alternator to mine on a 916?), but was the rectifier in the end. I've been told that the 3 phase rectifiers seldom give trouble, but this one worked at first, but broke down when hot. Started off at 14V, but soon went down to 12V after a few miles. Replaced with 2nd hand rectifier, and now charges to 14.2V at virtually all road speeds, with lights on! Idles at about 12.6V with lights on, and battery now reads 12.9V with ignition off.
I noticed that there was a small bulge and crack in the back of the old rectifier. Clearly something had broken down inside there.
So I'd strongly recommend the voltmeter, especially to those with the older alternators (that's you weeksy!
). It sits very neatly below the temp gauge, just like in Shazzam's pictures.
Well chuffed!
