Dopey Alternator

[ryana89]

Recently I've experienced some interesting intermittent electrical issue's

When I turn the car on (occaisionally) the battery warning light will stay on, even with light throttle applied. But if I turn the car off then back on again the light dissapears.

I know what your thinking, alternator/regulator is on the way out.
The alternator was reco'd just under a year ago (regulator died in a big way)

Then again this morning I started the car 3 times with the batt warning light on, so I got out the multimetre, and sure enough there was only 11.9V at the battery.
I gave the throttle a 'blip' and the voltage went back up to the normal 13.5ish volts.

I decided to do some more testing.
I recorded these results

With the car running (3000rpm) and no accessories on:

13.1 Volts @ battery, 13.7 volts @ alternator

Then again with all the lights on (3000rpm):

12.8 Volts @ battery, 13.6 volts at alternator

Roughly a 0.7 volt drop between the two

I have done the relay mod on both H/L beam, could this cause such a voltage drop at the battery?
Do you think the alternator/regulator/brushes, need reconditiong/replacement?

Any help/insight appreciated

[sports racer]

First place I'd be checking is the heavy duty cables hanging off the battery. Undo and clean all the ends (both cables). Clean where they connect to the body and alternator too so you're getting a good contact. Do the cable that goes from the body to the engine as well.

Cheers

Paul

[GTI JOHN]

I second that its cheep insurance. I just replaced mine and it made a big difference Day and night. let us know.

[ryana89]

Thanks fellow's, did what I should have done a while ago.

Scrubbed up all the connections from the alternator to the battery with some (high grit) sand paper and a few dabs of dielectric grease.
Only a 0.4/0.3 voltage drop now between the batt an alternator

Regardless I went to Jaycar and made list of parts I'll be buying to make my own leads up, with 2 gauge wire(overkill?).

Also think (hope) I found the reason for the batt warning light, there was a dodgy connection/plug on the exciter wire circuit.

(Should rename the thread to "Dopey Ryan" haha)