Voltage woes

[lowmileage]

I only take the car out at night 2x per year. On last years nightly (actually early morning) jaunt I noticed (with the lights on) a very faint glimmer of red light from the dredded Alternator light. None the worst for wear, after driving like that for a few hours I didn't notice any dimming of the headlights that would indicate a battery run-down condition.

Getting back to things a year later for this years early morning run, I installed a Voltmeter. What I notice is that without the lights on, I'm running 13 volts or a bit more - I have the voltmeter in a fairly obscure , but functional location. With both pair of lights on (without the "brights"), it goes to 12 or a bit more. With the brights, it's below 12 with a very, very faint Alternator glow. According to bills left me from the PO, I'm supposed to have a 65 amp Alternator. The Alternaor has the sticker "PB041" on it. Shouldn't I be running at or close to 14 Volts without anything and like 13 Volts with lights?
Cleaned fuse panel, replaced all fuses, battery is of good quality and under 3 yrs old, cleaned the alternator (red) to battery wire connection etc. I even put a "better" battery in there for comparative purposes and got the same results to eliminate the battery as being at fault. Lighting is nothing exotic (power hungry) - Wagner halogens.

[Tifosi]

Book here (for 55 amp internal regulator) says 3000rpm no load should produce 13.7 - 14.7V.

Full load (lights and everything going) should not drop below 12V.

It doesn't give any spec for idle speed output, but I can offer that mine puts out just about 14V with no load at idle, (Bosch 65 amp internal regulator), and never drops below 12 1/4V when things are turned on.

Book also suggests testing voltage at battery terminals rather than anywhere else as that's where the voltage has to get to when it's all said and done. (I've got a gauge hooked up in the conventional fashion too BTW)

How's your ground wire/strap and alternator junction contacts?

[lowmileage]

I cleaned up all Alternator connections, fender relays and other connections. New battery ground strap attached to cleaned (no paint) body panel. I'll take a better look at the underbody ground but I visualized it and it appeared good. I also try attaching my meter to the battery with the lights on and see how it compares to the gauge. Thanks Tifose

You can't test Alternator output can you with a Multimeter?

[Alfacliff]

There is also the large but not the largest red wire connected to the starter solenoid, corrosion on this wire, which connects the rest of the car to the battery has got a lot of bad problems. the battery goes to the solenoid, then back to a terminal block usually on the left front, on my 74, under the battery, then to the fuse block.
cliff

[lowmileage]

Quote:

Originally Posted by Alfacliff There is also the large but not the largest red wire connected to the starter solenoid, corrosion on this wire, which connects the rest of the car to the battery has got a lot of bad problems. the battery goes to the solenoid, then back to a terminal block usually on the left front, on my 74, under the battery, then to the fuse block. cliff

[Tifosi]

Quote:

Originally Posted by lowmileage You can't test Alternator output can you with a Multimeter?

[Alfacliff]

if you hook up an ampmeter to the alternator and check the current, it will tell you if the alternator is working. there are clamp on ampmeters that work on dc, most only work on ac. a simple test is for voltage drop from fuse box to battery or alternator. did you replace both wires, the one from the battery to the solenoid and the one from the solenoid to the terminal block? about a number 6 or so, a little smaller than the battery, but larger than most other wires in the car.
cliff

[lowmileage]

Quote:

Originally Posted by Alfacliff if you hook up an ampmeter to the alternator and check the current, it will tell you if the alternator is working. there are clamp on ampmeters that work on dc, most only work on ac. a simple test is for voltage drop from fuse box to battery or alternator. did you replace both wires, the one from the battery to the solenoid and the one from the solenoid to the terminal block? about a number 6 or so, a little smaller than the battery, but larger than most other wires in the car. cliff

[Alfacliff]

thats the one that sometimes gives trouble, either at the crimped ends or corrosion.
cliff

[lowmileage]

Quote:

Originally Posted by Alfacliff thats the one that sometimes gives trouble, either at the crimped ends or corrosion. cliff

[Alfacliff]

it always seemed silly to me to run the battery to the solenoid then back under the battery to the terminal strip that feeds the fuse box.
cliff

[lowmileage]

Quote:

Originally Posted by Alfacliff There is also the large but not the largest red wire connected to the starter solenoid, corrosion on this wire, which connects the rest of the car to the battery has got a lot of bad problems. the battery goes to the solenoid, then back to a terminal block usually on the left front, on my 74, under the battery, then to the fuse block. cliff

[lowmileage]

Quote:

Originally Posted by Tifosi Book here (for 55 amp internal regulator) says 3000rpm no load should produce 13.7 - 14.7V. Full load (lights and everything going) should not drop below 12V. It doesn't give any spec for idle speed output, but I can offer that mine puts out just about 14V with no load at idle, (Bosch 65 amp internal regulator), and never drops below 12 1/4V when things are turned on. Book also suggests testing voltage at battery terminals rather than anywhere else as that's where the voltage has to get to when it's all said and done. (I've got a gauge hooked up in the conventional fashion too BTW) How's your ground wire/strap and alternator junction contacts?

[Tifosi]

Sweet.

Glad to be of service.