Technical Voltage question

I hear ya. Said regulator was much more stable before I “cleaned” (messed up) the points. It was only after that, it started jumping around.

 

ground is good, all contacts are cleaned and there was no problem until I went it alone and cleaned the relay point on the old regulator with some fine sandpaper. But now that I have the hang of which way to adjust the spring tension on the new one, I’ll get there.

if nothing else, if other lurkers out there see my mistakes and learn from them, I’m fine with that.

 

To add to my comments I use an analog meter, an old Simpson 260 from work, when testing volts on generators. They are steady. The 3 brush on my 39 Indian cannot read volume with a digital at all. Goes crazy.

 

Is your voltage still jumping around? If you think it is the cut-out relay, a simple way to tell is to push down on the relay contacts. If the voltage becomes stable, that is your problem.

I've got a 57 T-Bird with a generator that I've had for 24 years. I had a voltage regulator fail maybe 17 or 18 years ago. I replaced it with one from NAPA. It worked fine for 3 or 4 years but the charge lamp started coming on intermittently. What I found is that the cut-out relay would fail to close intermittently. There is a spec for closing voltage and I adjusted it. It worked fine for a short while and started acting up again. With the cover off, I could manually close the relay and it would stay closed. If I shut the car off and restarted, it just would not close on it's own. I replaced it with another NAPA regulator and everything was fine. I took the failed one apart and could find nothing wrong. I should mention that I did have to tweak the voltage regulator setting a bit to get the voltage to where I wanted it.

Fast forward about 7 or 8 years and I'm at a car show leaving a restaurant and the charge lamp comes on. I didn't have any tools so I headed home. The next day I took a look at the regulator with the cover off and the cut-out relay just won't close on it's own. Didn't try to adjust it, just got another regulator. It has been working for the past 7 years or so. I think that they may be skimping on wire on the new units. The quality just isn't like the originals.

 

After working the vampire shift, just came home to tweak the spring tension. After going back and forth with too low and too high, I’m now sitting at just above 13 volts with lights on and mid 13 with lights off (via my analog gauge that was checked for accuracy by digital voltmeter) fully warmed up on a 65 degree day with a fully charged battery. Gonna let ‘er cool off and see what she does cold tomorrow. I have literally no accessories, don’t even have a heater motor, so I’m good with that if it stays true.

 

How are you determining what's "too high"?

Is that a "guess or by golly"? Have to use the shop manual specs. 13 volts isn't more than battery float voltage.

The shop manual (for example) shows a voltage regulation setting of 14.6 to 15.4 volts at 75 °F. on a standard Ford generator. 14.1 to 14.7 volts for an alternator.

 

You may haven’t read above so I’ll fill you in.

Old regulator swung from high 12s to low 14s in a single drive on a full battery and was pretty old. I tried to clean the contacts but likely made it worse, as the voltmeter and ammeter started flicking back and forth erratically afterwards. My mistake.

But I’d already bought a new one, put it in and it ran in the 15s. I verified the gauge with a digital voltmeter, and it’s accurate.

Some suggested that 15s was to high and is bad for the battery/generator.

I adjusted the spring tension on the new regulator, and will test again tomorrow, but I may have to tweak the voltage upward a bit to get it around 14v. I want to see what it does when cold.

So I guess it’s not “by gosh or by golly”, I’m doing what people are suggesting and trying to learn on the way, and it’s a Chevy not a Ford. And I’m in northern Washington so 75F is maybe one month a year.

And if anyone has a link to shop manual for a 35 amp Delco Remy generator with a mechanical voltage regulator such as this, I’m all ears.

 

Hey there- with the new regulator, not jumping around. I’m sure I screwed up the air gap on the cutoff relay. Trying to dial in the spring tension on the new one, getting close, going to see what it does tomorrow when cold.

It’s not easy but not difficult to work with this- I just need to find out what it does now when cold, warm, and everything between. I must’ve had the cover on and off 10 times this afternoon! But I’ll get there!

Great story on the T-Bird. I can imagine that things aren’t the same as they used to be- but now, with having to tweak the voltage with needle nose pliers instead of a screw, I can appreciate that option of an adjustment screw. In all honesty, I can’t imagine getting it right from a manufacturing standpoint every time with stamped steel, springs and rivets and expecting to to come out of the box perfectly. Seems like a bit much to ask.

 

Battery voltage, charging voltage, is not brand or make specific. Some manufacturers have different ideas on what is "correct", I suppose. 13 volts is likely too low and 15 may not be too high. It is temperature dependent. This is why following the shop procedure is important, battery state of charge, and normal operating temperature, and ambient temperature are all factors. The set point you select is different, depending on ambient temperature.

Generator charging voltages are also different than alternators.

Notice here on the chart there is a 1/2 volt difference across the board between a generator and alternator. A few tenths of a volt don't sound like all that much, but on a percentage basis, it is a lot. Yes, this is a "Ford" chart, but it shouldn't matter a whit and hopefully gets the point across.

 

Ok, I’m trying to catch up with your language here. And I apologize.

I’ll get some sleep and post tomorrow but I’ve been awake since 2am and want to digest the information.

picture as a Olive branch to those that have helped. Thanks to all and have a good night.