voltage regulator question (auto)

me

[djf]

Question for car enthusiasts:

I put a new starter and battery in the Impala. After I did it, the internal lights and dash lights, etc were flickering. To make a long story short, I replaced the alternator.

Bit the voltage at the battery was nominal... so I tried to adjust the voltage regulator.

The car has the original Delco-Remy voltage regulator in it. It consists of two coils, one is called the field effect coil, and one is the voltage regulator coil. There is a timy plastic button that adjusts the gap for the voltage regulator coil.

With the gap closed, the voltage at the battery is nominal. With the gap wide open, the voltage is high (about 15.5) I seem to get the best results if the gap is adjusted so there is sparking in between it.

So my question is this: assuming I'm right, that the gap should be set kinda in between open and closed, should I do that:

When all the lights are on, the blower motors, the wipers, I mean at what is about full load, or when the lights are off and drainage is at a minimum

Also, mechanical voltage regulators like this are notoriously susceptible to temp changes, so should I do the adjustments when the car is at operating temp? Or is cold good enough?

I know if I turn the button all the way out so that it's always open, the voltage keeps climbing and goes up to about 17 and I don't want to kill another battery.

Thanks!

[Prophet in the wilderness]

If all possible ( it they do make one for that year car ) go and buy a electronic voltage regulator.
Check ALL of your wires for corrosion, shorts, kinks, or breaks in the wire as the other poster said.
Wiring on a car is a nightmare, and I hate electrical problems on a car.
Just hope you didn't sort or fry anything in the dash or instrument cluster.
Oh yeah ? check you main cable coming from the battery to the engine, or from the engine to the firewall.

[Spktyr]

Also, I bet you are still using a mechanical points ignition system, aren’t you?

[raybbr]

I’m just wondering about optimal workings under load and temp, etc.

A fully charged battery should be between 13.5 and 14 volts. Anything higher will burn it up quicker.

Without knowing the current you're drawing it's hard to know what your actual load is. Do you have an ammeter?

[philetus]

Normal voltage to the battery is 14.3 volts D.C.

[PeaceBeWithYou]

Set it to where it is charging the battery at 14.5V max. with the headlights and A/C on high, at idle. Battery voltage at rest should be in the 12.5-13.5 range, much more than that and it will boil the water out, and cook the plates. Less and it will make the starter drag and work harder.

If it's charging consistantly, don't mess with the field adjustment, that's a points wear adjustment. Usually it's time to replace it if it isn't adjusted soon enough to prevent the points from burning or plating out.

[djf]

Pertronix is in the trunk.

But I’m working now on getting the starter/battery/running voltages correct. I got dim tired of the thing not wanting to start when it was hot.

[PeaceBeWithYou]

Forgot to add, there is an instrument cluster voltage regulator that can cause flickering if the charging voltage is off.

[cva66snipe]

Better to replace a regulator if possible than to spend your free time for the next week or three replacing or repairing fried wiring harnesses. That is no fun at all been there done that. If I even suspected regulator problems I’d replace it. I used to replace mine each time I replaced the alternator just as a rule.

[UnChained]

“But I was still wondering about where the voltage reg should be set, because I’m tired of putting the charger on it.”

Set the regulator to have charging stop above 14.25 volts. The contacts should make and break slowly, not so rapidly that you see a steady arc. Adjusted for continous break/make of the regulator contact might make the lights flicker so rapidly that you don’t notice it but that mode of operation will burn up the regulator contacts pretty fast.

If the normal make and break of the regulator contacts causes an obnoxious flicker then that means that the voltage in the system is changing rapidly. Normally the battery charging and discharging will smooth things out so that the voltage change between regulator on to off won’t be fast enough to be visible.

Since you can see an abrupt brightness change look for resistance in the battery circuit ie; post, cables, ground lug etc. With the engine off and lights on, use a sensitive DVM to look for any voltage drop across what should be a solid, low resistance connection.

I’d suspect that the battery had a high internal resistance but you said you put in a new one so that’s pretty well ruled out unless the “new” battery was stored for a month or so while full of electrolyte but in a discharged state.

I looked online for an electronic voltage regulator for retrofit on your car but came up empty. If that were available it would stop the flicker too.

Good luck

[djf]

Thank you! Your answer makes perfect sense.

My battery charger puts out 6 amps at about 14.3 volts, so I know where you’re coming from.

[Spktyr]

This is why I recommended that he switch to an alternator that is internally regulated. External regulators are getting harder and harder to find.

[HiramQuick]

Good advice.... there has been more maladjusted mechanical regulators than carter has pills. Field adjustment should only be touched with high erosion of points. I suspect that a new regulator is the best bet. Those springs get funny with age.... just like us old farts that remember them,

Max .... 13 v at the battery underload. How much new stereo add ons and such have been hung under the dash? CB Radios used to give auto electrics fits ... that and trying to get the noise out

[djf]

That’s part of the reason that if I can adjust it to work right, I want to keep it.

I’m not all bugaboo about keeping things original, but a big part of this process for me is knowing how things were designed and how they work. (or are supposed to work!)

And as far as I can tell, it is the original regulator.
Looks exactly like the pic in Toboldt’s book.

[UnChained]

“Set it to where it is charging the battery at 14.5V max. with the headlights and A/C on high, at idle. Battery voltage at rest should be in the 12.5-13.5 range, much more than that and it will boil the water out, and cook the plates. Less and it will make the starter drag and work harder.”

Please don’t use this setting since the regulator cutoff adjustment limits the charging systems maximum voltage. The maximum mainly comes into play with little or no electrical load and the engine well above idle rpm.

Trying to get to 14.5 volts at full load during idle will make the voltage in the system very high at no load and high rpm.

14.5 volts is a good cutoff voltage for charging a cool battery but I like to back down from that a bit to help prevent thermal runaway.

[Spktyr]

You do realize that inside your v-reg is a set of points and a bimetallic coil, right? Basically, it’s another failure-prone piece of equipment that got American cars their bad reputation.

[org.whodat]

Not going to read the answers, but the easy fix is convert the car to a one wire alternator. You can buy whole kit at summit racing, follow directions. If you really want to keep the old generator you bend the tabs on the spring retainers to adjust the point pressure.

Where do I send my bill??

[Spktyr]

You missed my comment above about a 12SI or CS130/144. :D

[G Larry]

What’s Hillary proposing now????

I’m for FREE VOLTATGE!!!

Voltage WITHOUT Regulation!!!!!

[org.whodat]

No did not read it!!

[org.whodat]

Forgot to add you were pretty well on the money!