Battery/Ignition light ruins day out scandal

[racingsnake]

Help! fellow wedgers.
Along the same vane as badreds problem.
Went off to Wales today for a PH tour (see "North Wales Tour" thread in General TVR) but had to turn back due to the battery condition/ignition light glowing.
It gets brighter as the revs rise and flashes also.
The car is running fine and we got home (another 50 miles) with no prob's.
The starter is turning over like a good un' and the dash voltmeter is hovering around 13.
A multimeter on the battery shows 15 volts (isn't that a bit much?)
What do you guys think?
Is it "overcharging" or something?
Is there a voltage regulator in the alternator that's goosed? or is it just a dogdgey earth on the light? Why do fools fall in love? and why do i still love my wedge despite it ruining this day i have been looking forward to for weeks? pah, tish, pants etc...

[jeff m]

The charging light glows when there is no output from the alt is not at 12v. When the alt turns it produces 12v so light goes out as both voltages are the same and there is no current to light the lamp.

Loose wire.

[GreenV8S]

The 'no charge' warning light is connected between the alternator output and the switched ignition circuit, and glows when there's a voltage difference either way. The switched ignition voltage is nominally the same as the battery voltage. It may be lower if there is a wiring fault, or if the alternator voltage is too high. Judging by the fact that the problem gets worse with revs, and the battery voltage (15V) is rather higher than it should be (13.8V) I'd suspect that there has been an electronic failure in the alternator and the output isn't being regulated properly. This sort of failure can also cause the battery to discharge through the alternator when the engine is off, so I suggest you disconnect the battery straight away to be on the safe side, then arrange to get the alternator tested and repaired if necessary.

[racingsnake]

Thanks guys.
I will check the wiring then get the alternator off and get it checked at my local leccy wizard.
The reading of 15v at the battery I suspect means it's not regulating properly as suggested.
All the best for New Year wedge fans Ta.

[hormone]

I have had this problem twice on the 200.
No electrical problems & a strong charge.
The light started glowing at about 3000 revs.
The first time the garage put a new alternator on but this was the second in 2 years so when it happened again a bit more investigation was in order.
It was the connector to the alternator breaking down.
Quick, easy & cheap to fix. A shame it spoilt your day.

[redwedge5]

I had a similar problem couple of years back. Car running fine, but red alternator light glowing. Also some of the instruments started reading oddly (can't remember which now). AA mechanic initially thought alternator problem, but just before leaving tried a new fuse in the instrument circuit, even though the one in place looked OK. New fuse and everything was fine again and has remained so!

[racingsnake]

All good stuff guys, will check out all of the above suggestions thanks.