Alternator not charging batery? Check your fuse
Discussion
I thought I'd share my recent discovery in case anyone's got the same problem.
When I started my Griff 500 the other day, the red light between the speedo and rev counter stayed on. This suggested the battery voltage was low, and sure enough, as I nursed the car home the voltmeter needle steadily dropped.
Prolonged probage with a multimeter revealed the faulty component was the 100A fuse on the +ve wire between the alternator and the starter motor. When I opened the fuse casing (on the right underside of the engine bay) the fuse looked intact. Looking closely and cleaning off a bit of corrosion, I saw the fuse had cracked completely in two but without losing any material. This was stopping the alternator supplying the starter motor and onwards to the battery. I replaced the fuse and all was well. I guess 10 years of heating, cooling and vibration finally did for the fuse.
Note that at first glance the fuse looked intact but had cracked. Like any fuse, if it had looked melted or blown it would still be necessary to track down the root cause before replacing the fuse.
Hope this is of use to somebody. Turned out to be substantially cheaper and easier than the average TVR wiring repair!
When I started my Griff 500 the other day, the red light between the speedo and rev counter stayed on. This suggested the battery voltage was low, and sure enough, as I nursed the car home the voltmeter needle steadily dropped.
Prolonged probage with a multimeter revealed the faulty component was the 100A fuse on the +ve wire between the alternator and the starter motor. When I opened the fuse casing (on the right underside of the engine bay) the fuse looked intact. Looking closely and cleaning off a bit of corrosion, I saw the fuse had cracked completely in two but without losing any material. This was stopping the alternator supplying the starter motor and onwards to the battery. I replaced the fuse and all was well. I guess 10 years of heating, cooling and vibration finally did for the fuse.
Note that at first glance the fuse looked intact but had cracked. Like any fuse, if it had looked melted or blown it would still be necessary to track down the root cause before replacing the fuse.
Hope this is of use to somebody. Turned out to be substantially cheaper and easier than the average TVR wiring repair!
Mine did the same, my reckoning is that the securing nuts help fracture the fuse when tightened up or at least put enough stress on it to shorten it's life. I posted up a thread a while ago on the the fuse and there were a few suggestions to alternatives although I never got round to doing it on mine.
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