Constant positive charge showing on the ammeter?

[Model56s]

I recently installed a 1-wire 6v alternator on my 49 Buick Super. under the generator and voltage regulator regime, the headlights immediately showed a large and constant discharge which eventually drained the battery. I can now use the headlights without draining the battery. However, The ammeter is now showing a significant and constant positive charge, only slightly reduced by the headlights.

 

Is this constant positive charge OK, or am I damaging something? Also, the alternator gets pretty warm.

[Bloo]

Check the system voltage at the battery with the engine running above idle. 7.4V is typical on 6V cars. The voltage is what should remain more or less constant, except maybe at idle, and probably even at idle with an alternator. Fully charge the battery first if it is even a little low. If it is about 6.3V or a little higher with the engine off, it's full or close and you will get a good voltage test with the engine running..

 

When you have a voltage regulator, the battery will draw current significantly while it's charge is a bit low, and then taper off it's own current demands from the generator (or alternator) as it gets full. The current shown on the ammeter should go up at first and then taper off. My guess is that the voltage regulator isn't working at all, is stuck high, and the voltage is going crazy and boiling the battery. A constant level of charge current is only normal on prewar cars with a simple cutout (no voltage regulator), like model A Fords and such. It was hell on batteries, but they got away with it because maximum charge current was set by a third brush in the generator to only about 8 amps.

 

1 hour ago, Model56s said:

under the generator and voltage regulator regime, the headlights immediately showed a large and constant discharge which eventually drained the battery.

That can't be normal unless the headlight bulbs were something huge and aftermarket. Just about every generator system from 1940 on has enough current available to run a pair of sealed beam headlights on high beam forever with some current left over, as along as you are moving. My guess is a Buick probably had a 45 amp system. A pair of new halogen 6v sealed beams draw about 16.5 amps on high beam, the old incandescent originals drew a little less.

 

 

 

Edited September 18, 2023 by Bloo (see edit history)

[37_Roadmaster_C]

I can not answer your question for sure, but I would expect the charge rate to drop significantly after the car is started and run for a while with no extra loads except the ignition.  It may be possible that the internal regulator is set to high or the battery may have a weak cell, or other issue.  My first troubleshooting test would be to check the voltage of the battery with a volt meter with the ignition off. Record this reading. next, turn on the headlights on high beam and monitor the battery voltage for 10-15 minutes with the car not running. Record the final voltage and the discharge time then turn off the headlights. Now start the car. Note the amp meter for charge rate and the battery voltage on the test volt meter. Rev up the car a little to about 2000 rpm (not critical, but revved up a bit) and note the voltage measured at the battery and record it. Let the car run revved up a bit for around 30m minutes or take the car for a 30+ minute drive. When you get home, measure the batter voltage again and note the voltage and the time running. Now for the part that is variable and somewhat unknown to me for an exact answer.  These readings will show the basic battery condition and the chargeing capacity of the alternator and battery combination.

 

I see @Bloo has replied while I was typing so I will post now ab see what was said.

[Rusty_OToole]

If the battery was run down it may take a long time to completely charge up. I had a 6 volt car that was off the road all winter. I charged the battery with a plug in charger, the car started normally and seemed ok.  A few weeks later I went for a long drive, the ammeter showed a charge for an hour at 50 -60 MPH  before it finally dropped to neutral. I was scared the generator was over charging but no, it took that long to completely charge the battery. Even though I thought it was charged up.

[Model56s]

Thank you all for your input. Bloo shared my concern that "the voltage is going crazy and boiling the battery". I bought the long-style 6v battery in July (1150 cranking amps, NAPA). I'll run the voltage checks as suggested; the battery is clearly full charged based on a static voltage test (6.35v) and the response from the starter. I'm wondering if I should put a resistor in the circuit...it shouldn't need this though.

 

The single lead from the alternator is connected to the two leads that were originally connected to the BAT and GEN posts of the voltage regulator: the 10g lead to one side of the ammeter and 12g lead from one side of the starter solenoid, respectively. This was at the suggestion of the local builder of the 6v alternators. He is the go-to for Model A owners for alternator conversions.

Edited September 18, 2023 by Model56s (see edit history)

[Rusty_OToole]

If the alternator is faulty you should return it and have it fixed or replaced under warranty.

[Frank DuVal]

4 hours ago, Model56s said:

The single lead from the alternator is connected to the two leads that were originally connected to the BAT and GEN posts of the voltage regulator: the 10g lead to one side of the ammeter and 12g lead from one side of the starter solenoid, respectively.

You connected the wire from the alternator to the 10 awg wire that was on the voltage regulator BAT terminal, right? And there was also a 12 awg lead there too, now also connected to the 10 awg and the battery lead? And of course with the generator gone, no leads to GEN or FLD are connected, right?

[Bloo]

8 hours ago, Model56s said:

I'm wondering if I should put a resistor in the circuit...

No.

8 hours ago, Model56s said:

The single lead from the alternator is connected to the two leads that were originally connected to the BAT and GEN posts of the voltage regulator:

The BAT wire is really what gets you connected. The GEN wire is just a piece of wire that runs between the generator and the regulator.

 

8 hours ago, Model56s said:

the 10g lead to one side of the ammeter and 12g lead from one side of the starter solenoid, respectively.

If those were both connected to the voltage regulator, something was wired really wrong on your generator system. The wire to the starter solenoid should have been coming from the other side of the ammeter. No wonder it didn't work. I wouldn't expect a 12g lead there at all. Does it look added?

 

EDIT: Another possibility is a 16g wire that originally ran from the GEN terminal to a SMALL terminal down at the starter. That was for gas pedal starting, which won't work correctly with an alternator, at least not without adding some more stuff. Do you still have gas pedal starting?

 

EDIT 2: I found a wiring diagram for 1950, but not 1949. It has a second 10g wire connected to the BAT terminal. It powers the horn relay. If you have that, you'll want to connect it to the wire you have coming from the post on the alternator.

 

Wiring you should have now:

 

1). Alternator post >> one side of ammeter, and also most or all accessory power in car (lights, etc).

2) Other side of ammeter >> starter solenoid post (the side that has the battery cable).

3) Starter solenoid post >> battery (the battery cable takes care of this).

 

Current flows from alternator, to first ammeter post (and where power is tapped for the rest of the car), through the ammeter and out the second post, down to the starter solenoid post, through the battery cable to the battery.

 

Edited September 18, 2023 by Bloo (see edit history)

[Model56s]

The response in this thread is very much appreciated.

Attached is the original wiring diagram (thank you Old Car Manual Project) showing the original connections regarding the starter solenoid, generator, voltage regulator and ammeter.

I found that for the car to start with the alternator installed and no voltage regulator, the 16GC lead from the outboard solenoid terminal had to be connected to ground and the inboard solenoid lead to the positive ammeter lead and the single alternator lead. The alternator lead replaced the generator's Armature lead ("A" on the schematic).

 

The vacuum starter switch on the base of the carburetor does not work and was replaced by an inline push button switch.

Edited September 19, 2023 by Model56s (see edit history)

[Bloo]

2 hours ago, Model56s said:

I found that for the car to start with the alternator installed and no voltage regulator, the 16GC lead from the outboard solenoid terminal had to be connected to ground

Is that is the little relay on the back? If so, yes, you have to provide power to one terminal and ground to the other to crank. Originally the generator had to be not charging (to provide ground) and the engine had to have no vacuum (to provide power) and the throttle depressed (also to provide power) to crank.

2 hours ago, Model56s said:

and the inboard solenoid lead to the positive ammeter lead and the single alternator lead.

That would crank all the time and never stop...., but....

 

2 hours ago, Model56s said:

The vacuum starter switch on the base of the carburetor does not work and was replaced by an inline push button switch.

So I am going to guess that you put the pushbutton inline with one of those two leads? Probably the hot one? A pushbutton inline with either one would work.

 

2 hours ago, Model56s said:

The alternator lead replaced the generator's Armature lead ("A" on the schematic).

That is confusing. For the record, the regulator's "BAT" terminal on a generator system is equivalent to the big charging terminal on the back of an internally regulated alternator. F(field) and A(GEN) are just wires that run between the generator and the regulator. If the generator's regulator were internal, like it is on some alternators, you would never see F and A. They would be inside.

 

2 hours ago, Model56s said:

<snip> to the positive ammeter lead and the single alternator lead.

The positive ammeter lead is the same connection as "BAT". That says to me you must have the alternator connected correctly.

 

For clarity, the alternator and all the accessories (lights, ignition, fusebox, etc. except horn) need to be connected to one side of the ammeter, the one marked (+) in that wiring diagram.

 

The other side of the ammeter (-) connects to the battery (and oddly the horn), via a number 10 wire, using the starter cable (at the starter) as the "last hop" to get to the battery.

 

If anything is connected to the wrong side of the ammeter, the ammeter will not read true. It is a flow meter and should be reading only current flowing in or out of the battery.

 

I'd still check the charging voltage to decide whether there is any problem with the alternator.

 

 

 

[Model56s]

Hi Bloo, much obliged!

“Is that the little relay on the back?” It is, and agree with your point

”…crank all the time…push button…” The push button is connected to the inboard (little) solenoid lead, either would work since the switch is in series.
“That is confusing. For the record, the regulator's "BAT" terminal on a generator system…” I chose the “A” lead due to the assumption that the current flows from the commutator (armature) and its wire gauge on the schematic . The 1949 generator had no internal regulator.

 

The schematic is aligns with your observations regarding the ammeter connection.

 

[Model56s]

Update, and to close this out for those looking to convert to an alternator. The charging settled back to slight positive while running, so that indicates the battery needed charging and when charged drew less current. The slight positive charge remains when the headlights are on.

 

it is nice to drive at night again!

[EmTee]

11 minutes ago, Model56s said:

...so that indicates the battery needed charging and when charged drew less current.

That's always the first thing to check and correct if necessary before further troubleshooting.

[Model56s]

Agreed. I charged the battery when I got it in July and the voltage read 6.35, so I figured it was charged. My concern was overcharging the battery.

 

I don’t have a feel for how long to charge, or at what rate. My charger has a 2A and 6A setting, but no longer an issue!

[EmTee]

When in doubt, I use a battery hydrometer to check the electrolyte.

[Model56s]

12 hours ago, EmTee said:

When in doubt, I use a battery hydrometer to check the electrolyte.

Now see, that would have been logical! 

[Jack Bennett]

On 9/17/2023 at 4:03 PM, Model56s said:

I recently installed a 1-wire 6v alternator on my 49 Buick Super. under the generator and voltage regulator regime, the headlights immediately showed a large and constant discharge which eventually drained the battery. I can now use the headlights without draining the battery. However, The ammeter is now showing a significant and constant positive charge, only slightly reduced by the headlights.

 

Is this constant positive charge OK, or am I damaging something? Also, the alternator gets pretty warm.

I’m thinking you have a bad battery, and that may have been the problem you assumed to be the generator-regulator.

A new battery is not necessarily a good battery as they get damaged in storage, during shipping, and any other damage, such as freezing, after purchase.

A one wire alternator has a built in regulator, and, unless it is bad the charge output should match the drain on the battery.

Of course, bad wiring, bad grounding and a improper ammeter will affect the charging, automotive circuitry, also.

[Model56s]

On 10/6/2023 at 11:04 AM, Jack Bennett said:

I’m thinking you have a bad battery, and that may have been the problem you assumed to be the generator-regulator.

A new battery is not necessarily a good battery as they get damaged in storage, during shipping, and any other damage, such as freezing, after purchase.

A one wire alternator has a built in regulator, and, unless it is bad the charge output should match the drain on the battery.

Of course, bad wiring, bad grounding and a improper ammeter will affect the charging, automotive circuitry, also.

Thanks Jack and at the time that also crossed my mind, but the charge settled down a little over a week ago and now reads slight positive. All good.

[pmhowe]

This has been an interesting thread. I’d like to revive it.

 

I am slowly working towards getting my 1935 Cadillac Series 30 V8 to the point where I can reliably take it on long trips (Long trip for it and me will be about 100 miles, at least at first.)

 

My concern: I am concerned that the charging rate never drops to near zero on my car, either.

So far, the longest trip I have taken is ~20 miles. On all these short trips, the ammeter shows a consistent 15 to 15.5 Amp charging rate - beginning of trip to end.  The car has a standard, large 6V lead-acid battery.  The battery charge at the beginning of the trips and at the end, after the car is shut off, is circa 6.35 - 6.45 V.

 

According to Cadillac, the Delco-Remy generator used in 1935 is a two-brush Delco generator. Apparently, Delco made two brush generators with either of two circuits, a Circuit “A” generator with the field externally grounded and a Circuit “B” generator with the Field circuit internally grounded. I checked the generator, and the Field is internally grounded, confirming that it is Circuit “B”.  The Delco generator Model Number appears to be 933B, but it was hard to read (see picture).

 

The voltage regulator is an aftermarket one which may or may not be correct. (I’m after engineering and performance correctness, not necessarily authenticity correctness.) I have included some pictures. The Field terminal on it is grounded. The points are not visible in the picture, but they are spotlessly clean with no pitting.  I have cleaned every electrical connection I can find, and have tested for connectivity. All is good there. On my next drive, no change: Charge! (At 15 Amps.)

 

So, what to do?

 

Is everything fine and I’m worried over nothing?

 

Should I drive it enthusiastically and see if I boil excessive water out of the battery? I would think the generator can happily generate 15 amps all day, without suffering - but I'd like confirmation.

 

Do I need a different regulator?

 

Or what?

 

I would like your advice.

 

And of course, thanks for the help,

 

Phil

Edited October 21, 2023 by pmhowe (see edit history)

[Bloo]

The battery voltage when shutting down suggests it isn't overcharging, but it is very hard to say. I am going to assume this is positive ground because that regulator says 6V POS on it, and I can't remember what year Cadillac switched to negative ground.

 

You might need to do a really good comparison of the wiring with whatever is in the shop manual. I'll bet that's not the type of regulator Cadillac put on it, but if it is 6V, positive ground, and 2 brushes there is no reason it shouldn't work.

 

1935 is real early for 2 brush. I know there were some 1936 LaSalles with a 2-brush system that was shared with Pontiac police cars. The regulator had 6 terminals. That would have been a negative ground system though, so probably not the same parts as a Cadillac.

 

With a battery that is not low or run down, and the engine running faster than an idle, so that it has enough speed to really charge, check the voltage at the battery. Also check the voltage between the BAT terminal on the regulator and the generator case. The voltage regulator should be regulating, and holding the voltage down to about 7.4 or 7.6 at room temperature. The service manual should tell you what voltage the regulator is set at. If it is running away, going up to 8 volts or something, then the voltage regulator is not regulating for some reason. The lid needs to be on because without it the setting changes, and the regulator base always needs to be grounded.

 

There is also a current regulator, but that should not be doing anything under normal circumstances with a full battery. It is probably the left relay in the second pic. It is probably set too high, because 1935 era generators are smaller than typical. That doesn't mean more charge current. Not really. The current regulator's only purpose is to limit the generators maximum output to a tiny bit over the generators rating. How much current actually gets drawn only depends on ignition, lights, accessories, and how dead the battery is. A peculiarity of generators is that unlike alternators they will happily try to put out way more current that they are rated for if asked, and will burn up trying. Normally the only time you see a current regulator working is when the battery is half dead and wants a whole bunch of current to recharge. The battery may ask for more current than the generator can safely give. The current regulator is there to protect the generator in that situation.

 

But yeah, check the charging voltage. That will be the biggest clue.

 

Edited October 21, 2023 by Bloo (see edit history)

[Grimy]

13 minutes ago, Bloo said:

I can't remember what year Cadillac switched to negative ground.

1946

[pmhowe]

I had hoped to get back to this sooner, but some household projects interfered.

 

The car is very definitely 6V positive ground. My error, I should have stated that in my first post. Also, the regulator on the car is very definitely not the correct OEM model.

 

I believe the generator on the car is the original one, although it looks to have been rebuilt at some time.

 

Cadillac very definitely used a two-brush generator in 1934 and 1935. Cadillac Preliminary Service Information (1934) states “The generator is of the shunt wound current control type. It has no third brush and no adjustment is provided”.

 

I took the car for a five or six mile spin today. The battery tested at 6.34 V before I started the car. The car started after less than five seconds on the starter, so I didn’t drain the battery excessively.  The ammeter read 15 +/- 1 Amp or so while driving (It hopped around some).

 

When I got back home, I tested voltage from battery to ground and from the regulator Batt terminal to generator case. The measurements were made with the hand throttle advanced somewhat. I didn’t have a tach on the engine, but would guess somewhere around 1500 - 1700 rpm. The measured voltages were 9.87 V across the battery terminals and 10.64 V from the Batt terminal on the regulator to the generator casing. I don’t know why the values differed. At any rate, it appears that the voltage regulator is not working properly, as you suggested.

 

It didn’t look to me that the voltage regulator is adjustable. I guess I need to buy a new regulator.

 

Thanks very much for your help. Of course, I would appreciate any further thoughts.

 

Phil

[Bloo]

The extra 0.77v is lost in the wiring and grounds. Of course we would always like less, but I don't think that is too far out of line. The voltage is way too high as I'm sure you noticed. Make sure the generator, regulator , etc are all grounded good, and assuming the regulator is mounted on the body, that the body is well grounded too. The regulator might be adjustable. One of those relays controls voltage. If one is wound in *only* small wire that's probably it. It is basically a relay across the 10.64 volts you saw, and that should have pulled it down and shut down the field, causing the voltage to drop, causing the relay to contact again, causing a charge, etc. It happens fast normally and the points buzz when they regulate.

 

So, it either...

1) has a burned out or disconnected voltage regulator winding, and the relay isn't trying to pull down at all (least likely)

2) is out of adjustment (maybe)

3) is not seeing the whole 10.64 volts due to a difference in ground, in other words a not solid connection between the base of the regulator and the generator case. (If I were a betting man, I'd go with this, but its always a crapshoot).

 

If you try to adjust it, know 2 things to avoid chasing your tail.

 

First, the temperature matters. Check the shop manual. The voltage at the battery on a 6 volt car is usually about 7.4-7.6V (tenths do matter) with the regulator at room temp. The lower end of that range tends to be for cars with over-engineered charging systems (like post-1939 two brush systems of 30 amp or more) and the high end for tiny 15 amp third-brush-plus-a-regulator systems that just barely work. The manual will know what the voltage should be at what temperature.

 

Secondly, the setting changes with the cover off. You have to have the cover on to test because the voltage will be different. The cover affects the magnetic field in the relays. It also might help to leave the lights on for a couple of minutes with the engine off before each try at measuring the voltage, so you don't get fooled by surface charge on the battery.

 

The spring tension on the little spring on the voltage regulator relay is the setting. A really tiny bend at the stationary spring anchor changes it.

[Oldtech]

Great explanation Bloo. I might add that it is much easier to adjust these nowadays when we have access to inexpensive digital volt meters that can easily measure the tenths. When I was young and needed one I didn't have one. Often trial and error. 

[pmhowe]

Further progress on my car’s charging system:

After reading Bloo’s response, I systematically went through the charging circuit (checking the base of the regulator and the generator case connection first) and got the following:

 

1. Battery terminal to Cutoff switch. (0.00 Ohm)
2. Cutoff switch terminal to terminal, with switch in “On” position.  (0.00 Ohm)
3. Regulator Field terminal to regulator base. (0.00 Ohm)
4. Regulator Field terminal to generator body. (0.00 Ohm)
5. Generator body to engine block. (0.00 Ohm)
6. Regulator Field terminal to battery ground strap. (0.00 Ohm)

 

That’s reassuring, as I spent a whole lot of time inspecting and cleaning terminals, wiring, and connections.

 

So, the good news is that the circuit appears to have good connectivity. The bad news is that I need to adjust the voltage regulator.

 

The worse news is those clever folks from Cadillac made removing and refitting the VR on this car a real PITA. (Removing and refitting the generator is even worse.) I decided the less aggravating and more sensible route would be to replace the regulator with a new one. I’d like a spare, anyway.

 

The regulator on the car is an Ace VR 2103.( It is not a direct replacement for the original factory supplied unit. The original factory unit did not have a voltage regulator but only had  a current regulator and a cutout. However, the generator is a two-brush generator.) I purchased a Standard Ignition Products VR - 1, which is a 6V positive/negative ground unit used on 1940s Cadillacs and many other vehicles and is similar to the Ace unit.

 

I disconnected the battery, installed the new regulator, polarized the system, and started the car. I did not measure generator output voltage through the regulator, which I should have done.

 

To my surprise, when I raised the engine rpm to an estimated 2000, the ammeter was registering close to 30 Amps, which is far too high for my comfort. I didn’t make an opportunity to run the car long enough to see if the current would drop down as the battery  recovered from startup.  I need to do that. But, still, 30 amps seems silly. The car had started easily and the battery charger had said the battery was near full charge (6.35 V) prior to start. I’m beginning to think that I have a bad battery. However, I have no sound technical reason for saying so.

[37_Roadmaster_C]

don't worry about a 30 amp charge until you have had a chance to drive it a bit. These systems pour the coals to things at first, then calm down. Modern GM vehicles will charge at close to 100 amps for a few minutes after a cold start, then calm down. Actually be glad you CAN charge at 30 amps when needed so you don't discharge the battery driving at night with the radio playing...

Edited October 31, 2023 by 37_Roadmaster_C (see edit history)

[pmhowe]

Closure. The charging system on my Cadillac is now working as it should. I took it out for a ride today, and the needle on the ammeter returns to near-zero after a few  minutes driving. Thank you for all of your help.

 

Some of you may remember the radio host Paul Harvey. He had a show called “The Rest of The Story”, where he addressed in depth particular topics of interest.

 

So, here is “the rest of the story”: The last few days have been cold here, and I chose not to work on the car. Instead, I looked through the Yellow Pages and found a generator and alternator repair shop in a small town near Boone. I took the old regulator in to have them adjust it.

 

The shop was in a small building that had probably been a one-bay service garage years ago. When I entered, it was like entering a time warp. It was just like the ones my father used to take me to when I was little and he had work done on the family car. It was slightly dark, the concrete floor was totally black from years of exposure to grease, oil, and dirt, there were a few overhead fluorescent lights, and a kerosene heater trying its best to keep the place warm.

 

Stacks of parts on shelves. And old tools. Lots of them. There were the usual mechanics tools, but also large and small presses, a tool that would firmly hold a generator and had a special screwdriver setup for removing the big machine screws that hold the field coils in place on a generator, a small lathe that I would give my eyeteeth for, and - over against the wall - an analog tester for generators and alternators. It was probably  the newest instrument there, since I think alternators didn’t become common until the 1960s. There was just one person there; the owner.

 

The owner was probably not as old as I am, but I would guess he was well into his seventies. Picture someone who looks like Earl in the comic strip “Pickles”, but with bib overalls and an old engineer’s cap.  He used the analog tester to adjust my regulator. I enjoyed watching him work as - from what I have learned from this thread and reading Delco-Remy Bulletins and The Motor Repair Manual, I understood most of what he was doing. He worked on the regulator for about 45 minutes until he was satisfied with its performance. I was pleased to see that he placed the regulator cover on the regulator after each adjustment and before each test.

 

When he finished, he returned the regulator and I asked him what I owed him.  He thought for a moment and said “Ten bucks”. Ten bucks!  I really was in a time warp.

 

I didn’t have a ten dollar bill, but I had a twenty. I gave him that and said his time was worth more than ten to me. When I left with my regulator, he had a smile on his face and I had a much bigger smile on mine.

 

When I got home, I put the newly calibrated old regulator back on my car, did the polarization and it was ready to go. I’ll save the new regulator for a spare. But, first, I will have it calibrated at my favorite shop.

 

Phil

Edited November 4, 2023 by pmhowe (see edit history)

[Frank DuVal]

👍

[37_Roadmaster_C]

You did well!  The old shop you found is a rare thing these days. Nothing beats the knowledge and skills of real world professionals!

[Model56s]

Great story! I also appreciate Bloo’s insights.