VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Battery Gauge / Left stranded

Hi, 1954 Bel air here.

I was driving home from a 125 mile trip today and was left stranded.

I noticed my turn signals stopped working and my lights started dimming. I pulled over when the car started to sputter. I parked it in a lot and it would not start again.

When I got it home I cleaned all of the contacts on the starter and the Generator. And charged the battery which is only about a month old.
It has been converted to a 12 volt system. I took it out for a test drive. It started right up but after a few miles of driving, the lights started to dim so I drove it home. It now will not start.

I am thinking the generator needs to be rebuilt.
My battery gauge reads a little to the left of the center dot. I thought I remember it reading to the right of center but I cant remember.
The needle still touches the center dot but it is to the left of it. Is that where the gauge should read or is it an indication of a bad generator.

Trying to trouble shoot this thing. Thanks for any help.

A lot of questions before I would start to answer your problem.

You say 12-volt. What has been converted? Generator? Alternator? Items operated with resistors? ect

My first guess is that you have a voltage generating problem.

The amp-meter needle must always point to the right when the vehicle is running at speed.

I don't know how to refer you to this post, so will just paste it in.
Don't leave home if the needle isn't to the right of the dot, at high idle.
You can do a quick system test by turning on the headlights for 15 minutes, or so, engine off, then starting the engine and observing the gauge, with the lights off.
Raise engine speed above high idle and the needle should go well to the right of the dot (center).
That indicates a healthy charge rate and you likely won't get stranded, unless something fails during your trip.
Did you change both the generator and regulator when converting?

I've seen several posts about the ammeter's behavior, so I'll jump in with a crude explanation.
The electrical loads on your car are the lights and coil and, maybe a radio.
Power can go from the battery to the loads OR from the generator to the loads.
If the generator is making more than the loads need, the extra can go to the battery.
Now the clever part:
You can think of a properly connected ammeter as a flow meter in a waterline.
Think of a vane sticking down into the flow (some are actually made that way.), with a needle sticking up on the outside.
Now, with the battery connected to one terminal of the ammeter and loads AND generator and loads connected to the other, you're set to see charge system performance.
You can see that if the loads are on and the engine not running you have flow from battery to loads, pushing the needle to the left (discharge).
Now say the engine is running and there are NO loads turned on.
Whatever current the generator makes goes to the battery, through the meter, pushing the needle to the right (charge).
Of course both are happening in normal operation.
If you are clipping along at some speed, the loads will draw their usual current, which will be supplied by the gen, likely with some left over.
There is a NET CHARGE current that goes to the battery and the needle goes to the right, charge.
At some speed, the gen puts out exactly what the loads need and the needle stays in the middle.

SO a common situation is that you were out watching submarine races last night, by the river near your house.
You were out there so late the girl's father stormed out to find her and took her home.
You drove the two miles home and went to bed, after a glass of milk and a cookie, leaving your battery seriously depleted.
The next morning, you go out to drive to the grocery store where you are a bagboy, while studying for your PhD in Astrophysics.
You wanted Art History, but your parents knew that was a dead end and wouldn't pay the tuition for it.
Anyhow, the car started right up, because you have a good battery with a reasonable amount of STORAGE CAPACITY left.
The engine idles down to a smooth 400 RPM, since the choke is keeping it niice and rich.
You have the radio on, hoping to catch a Beach Boys song and the sun isn't up yet, so the headlights are on too.

You are running, but the battery is discharging, to run all those loads, so the needle is going toward the D side, pretty smartly.
But then you get your seat belt buckled and head out.
You accelerate slowly, so your blown muffler doesn't disturb the neighbors.
By the time you get up to 20-30 mi/hr, the genny is putting out enough to carry the loads and the needle is sitting about in the middle of the scale.
At last you get to the main road and, with some roaring noise, get up to 45 or so. At that speed the genny is putting out more current than the loads need, so some is left over for charging the battery.
It's a ways to the store, so you keep on truckin' and notice the needle is quivering a little and slowly returning to center scale.
Now the current produced by the gen has raised the battery VOLTAGE to its maximum value (so as not to overcharge and damage it) ans is reducing the current to a value that just maintains the loads AND keeps the battery at max voltage.
I could go on about how the regulator works, but for now all you beed to know is that last night you ran the radio for an hour, drawing 10 Amps.
That's 10 Amp-hours of current you used, 60 Watt hours, roughly, of ENERGY.
SO this morning, your gen charges at 40 Amps for a while, until the battery voltage rises to the max value set by the regulator adjustment.
It cuts back to 39.5A, then 39A, then 38.5A and so on, actually in VERY small steps, which aren't really steps at all.
When you have driven long enough for that varying current, multiplied by the time (very small periods) spent at each step to equal 10 Amp-hours, you will have recharged your battery fully and you'll be ready for more races, IF you don't forget and leave the Beach Boys playing when you get to home.

I don't know what got me started, but that's what your ammeter is telling you.
We can cover regulator function later, but there are three functions: cutout, voltage limiting, and current limiting.
They keep the battery from discharging back through the regulator when the engine is off, limit the charge voltage, as above (keep from damaging the battery), and limit the charge current (can go high into a dead battery and, maybe a lot of loads turned on, which can exceed the current carrying ability of the wires in the gen and smoke something).

BTW, that multiplying of instantaneous current by small time periods and adding up all the answers is the calculus function called INTEGRATION. The product of Volts and Amps is POWER, the rate of doing work, or supplying energy. The integral of power, over time, is energy, the total amount of work done or energy supplied, like to the battery.

A decent 6V battery might be rated at 100 Amp-hrs, or 600 Watt hours, enough to run a 100W bulb for six hours.
One horsepower .is equivalent to 746 Wats, so that battery could run a one horse motor for (600/746)=0.81 hr, or 48 minutes. MINUS some considerable inefficiencies we'll overlook, so I can get to bed.
WL

Wilson.

Well, I checked the Generator.

Hooked to power it will spin like a motor, but hen I start the car, it is only kicking out 1/2 volt.

The car was converted to 12 volt before I bought it. It has electronic ignition and the regulator looks new. I assumed that it had to be a 12 volt generator because of the 12 volt conversion and I am not sure how to tell if it is a 6 volt or 12 volt generator.

I considered switching over to an alternator but it seems like a lot of hassle and from what I understand I can no longer use the ammeter battery gauge in the dash if I do this. Also, I didn't have any problem with using a generator before this issue.

I am thinking having the generator rebuilt for $200. might be my best bet. Wouldn't it have to be a 12 volt generator?

As stated above, more detail of your conversion is required.

I had a problem with my 53 where the lights would dim and it was intermittent. I checked everything to make sure all the units were working properly, no problem. Finally I started checking all the connections one at a time. I started at the generator and was working towards the battery, when finally found the problem was on the back of the amp gauge. I check only one side and when I tightened it, it move just a very little. Problem went away.

Don't know if you still have a voltage regulator, but that could cause the problem. If you start the car and turn on all the lights, radio, heater etc., your amp gauge should indicate that the system is charging. Needle goes to the right of center.

Yes, the generator would need to be 12 volt. Have you owned and driven this car for a period of time like a few years or is this a new purchase that you are working the gremlins out of?

If you have driven this car for awhile, we can assume this new 12v change has worked fine for awhile and something has changed or failed. Take the generator to a shop and have it tested/rebuilt. Make sure the shop is familiar with old generators.

If this car is new to you, then get the generator tested and confirmed to be 12v. You might then need to verify the regulator and or wiring as people can do some funky things with wiring. I'm hoping you've owned this for awhile so that this is a "repair" rather than a "figure out what the heck someone has done" situation...

The ammeter gauge doesn't care whether you use 6 volts or 12 volts. It is measuring amperage and not voltage. And it doesn't matter if you are using a generator or alternator. I am currently still using 6 volts in my car but I have a 6 volt alternator. All I had to do was bypass the voltage regulator. Because it is 6 volts I didn't have to change or alter anything else on the car.

As stated, the ammeter gauge does not care about voltage or whether it comes from a battery, generator or alternator.

The ammeter itself is indeed a weak link though if you switch to an alternator as one of the biggest advantages is the higher output current of the alternator which can make the ammeter go poof.

The ammeter is in series with all electrical loads so ALL current running everything will be going through it. If you have a fairly discharged battery, run the headlights and a heater at the same time, the alternator will be able to provide more current than the original generator in this situation and all this current is flowing through the ammeter, likely exceeding what the ammeter coils can handle. The ammeter becomes a fuse rated at maybe 40-50 Amps on a 50's car and maybe 30-40 Amps on an earlier car.

There are workarounds such as replacing the guts with a voltmeter or adding a shunt to the original gauge so it only shows/flows a portion of the total current flowing. You may get by for a while short term without doing this but at some point you will have a battery nearly dead and the current will blow the ammeter and you'll be at the side of the road.

I ended up taking the generator to a rebuild shop. I had them check my work and the generator was actually good.

I tested the generator while it was in the car, so maybe a bad ground?

I ended up running a new field wire to the regulator, and replaced all of the connectors at the generator. I also polarized at the generator and regulator just to be sure.

Everything seems to be working now and the battery gauge is in fact right of the center mark.

I don't think this is quite right, Tim.
The ammeter is in series with load current going from the battery to the loads.
But it's not in series for load current supplied by the alternator.
The alternator is connected to the load side of the meter, so when it's putting out current that current goes first to the loads and then, if there is extra, it goes to the battery.
Yes, a big alternator feeding a stone dead or shorted battery can produce high current, depending upon its design.
If you actually see very high charge current, turning loads on will take some of the current directly from the alternator, keeping it from going through the meter to the battery.
Another way of saying this is that the meter ic connected to read NET current to/from the battery.
If you are drawing 20A for loads and the alternator is putting out 20A, then the needle will be centered.
Unless you have a very large battery, it's likely to come up to the limiting voltage set by the regulator before drawing enough current to fry the meter.
There's no need for an oversize alternator, so when choosing one just pick a size able to supply more current than the max load, but only a few amps more.
Also, a fuse or circuit breaker should be used in the alternator output lead, to protect from the overcurrents discussed above AND to blow if the alternator develops an internal short, from bad diode(s) or insulation breakdown.
Wilson

It takes time and patience to troubleshoot electrical issues. You need to know how to use the basic voltage and resistance measuring functions on a volt-ohm meter. You need to logically and in an organized manner trace each circuit end-to-end.

The first steps I take are to test and eliminate any bad connections, broken wires, and bad grounds. You will be surprised how many times that resolves the issue.

We are getting off topic with the ammeter detail as I was trying to dissuade the OP from adding different variables to his current situation. A fried ammeter is indeed a known and regularly addressed detail when adding an alternator that we keep hearing about when people do this upgrade. Indeed if it is fused it will help address this, as would choosing 12v over 6v, but many people do not have an electrical understanding and are actually switching things out to avoid troubleshooting a present 6v issue and in turn make things even more complex by introducing new variables lol.

Back to the original issue - good that the Generator tested good. Do you have a service manual for the car? They usually have very useful instructions for testing the charging and that would be good to check occasionally now that something odd has happened. Follow Rusty's advice and go over connections and wire condition, especially grounds as I suspect if everything suddenly is working fine, it is connection related.

I am also leery of fully trusting even a new battery. They are not made like they were 20+ years ago and can be weak from the get-go. I'd recommend a load test on the battery to be sure.

I take it that you have had this car for a while and it has always charged fine for you prior to this incident?

I took the car out for a run tonight and it ran well. When I first started the car the ammeter, battery gauge, was right of center.

After about 5 minutes with the lights on the gauge settled a little less than 1/2 but would only occasionally rise to a little above center.

When I returned home, I turned the lights off and with the car idling the battery gauge registered at center.

With the high beams on at idle I get 11.5 V at the battery
With all lights off at idle I get 11.76 V at the battery

With the car off it is showing 11.93 V

These numbers look ok?
Yes, I do have a manual. I did have to put a new battery in the car about a month ago. I have only had the car for 3 months.

These voltages are all low. A charged battery will be over 12.5volts. Once running you should be seeing 13-15v being applied to the battery. Haven't worked on 12v stuff for awhile so forget the specific numbers but yours are too low and the battery will be discharging. Need to look at the regulator next. It would need to have been changed for 12v operation so check the numbers on it to make sure it is correct.

Have you driven it much over the 3months you have owned it to know if it was working properly prior to this incident? 3 months is not long so wondering if the 12v conversion has been done correctly...
.
If you have a battery charger, charge the battery overnight and then check the battery voltage in the morning. Measure it first with everything off. Then measure it with the headlights on for a couple minutes.

With the proper tools and understanding a voltage regulator can be adjusted to put out more voltage. Canadiantim is correct, you should be getting at least 13-15v.

Thanks for all of the help.

If I end up needing a new voltage regulator, what should I buy?
I have a 12 Volt battery and generator.

Try hard to find someone local who knows this stuff.
If you don't have burned up contacts or an open coil, your reg may well be OK.
Millions of them lasted for decades!
I could describe the function, but don't have time for all that typing right now.
Even with the description, you'd need to know exactly what to do AND to have a deft touch to do it properly. Most people don't understand them and treat them as mysterious black boxes, which they really aren't!
There are lots of regulators available for tractors, which may be an easy way out for you.
https://www.griggslawnandtractor.ne...msclkid=96aaeadace2413ea00e1b5314d1eb66a
Wilson

So I should very lightly open the field (far right terminal) contact to increase voltage out to about 14.5 Volts?

The Battery terminal (far left) contact is tied in with the middle contact. Those should remain closed or open when the car is off. Mine are closed.

Would the below NAPA regulator work with my 12 volt generator in my 1954 Bel air. It is 35 AMP and appears to match the mountings to the firewall. It is from a 1962 Bel air. Thanks.


https://www.napaonline.com/en/p/ECHVR126

It's really hard to say, not knowing the characteristics of your generator, but I expect so.
Some regs have four terminals. I assume you have a three terminal one?
How about posting the numbers from your generator's nameplate to see if anyone can relate it to a car model?
Wilson

Summit Racing may have a little more quality control than NAPA, but I have no real info, of course.

https://www.summitracing.com/parts/smp-vr20?seid=srese2&utm_source=bing&utm_medium=cpc&utm_campaign=Brands+|+S&utm_term=4582077271746411&utm_content=GSAPI+5ba29db72d536

Wilson

Yes, my regulator has three terminals. My generator does not have a name plate. All I can see is this stamped on the Generator:

There is an S in a circle. There is a large W. And the numbers: 11000181
5 73

Do you think the above NAPA Regulator will work?

Very likely.
Double check the wiring.
The field is the small wire, to FLD.
You should verify the ARM and BAT wires before connecting.
WL

Well, everything is up and running. Hopefully this thread will help someone looking for a regulator that will bolt up to the firewall and work with the 12 volt conversion with 12 volt generator on a 1954 Bel air.

The Napa regulator: https://www.napaonline.com/en/p/ECHVR126 worked for me. I had a hard time finding information on what regulator would work for my application. It has been a long time since I messed with regulators.

One thing I did notice; My new regulator has grounding washers that fit into the rubber grommets that the screw goes through to attach to the firewall and my old regulator did not have those. I am wondering if that was crating a grounding issue.

No matter, I destroyed the old regulator when trying to clean the contact points anyway!

Good.
The reg certainly needs a ground to operate.
It can deal with current without ground reference, but it cannot read voltage without a ground.
There may be regs with a ground lug, but I'm not sure.
If so, it wouldn't need the ground through the mounting screws.
WL