Generator verses Alternator

[DR]

Has anyone hooked up an Alternator to there 1930 Model A. How did it perform let me know the pro's and con's. Also should the battery terminal going to the Alternator be negative or positive. One connection goes to the transmission should it be hooked to the positive post on the battery. We are still learning about the car. I think the terminals were changed around and this could be the reason for the generator and switch burning out? Please share your expertise if possible.

[Sparky]

It would help if you told us what style alternator you are considering. You can go six or twelve volt, positive or negative ground.

[Kurt in NJ]

I have 40 years on the generator I rebuilt as a 16 year old, the only thing I have done is add a few drops of oil to the rear bushing oil cup.

I have direct fit Halogen bulbs.
I never use a battery tender.
My Optima battery is 14 years old, when I had regular 6V batts they would last 7-9 years.

Many that use alternators also do other modifications --water pumps with "improved" bearings --the alternator needs a tighter belt--
Battery shutoff switches so the battery doesn't go dead sitting ( one wire alts use some electric all the time sitting to keep the regulator ready)
Some people have the "need" to make improvements ---I feel that each modification requires other modifications to make it work, and the more modifications you make the less of the fords original reliability is left ----easy to fix on the side of the road IF there is a problem.

[Milton]

When I aquired my 1930 Tudor it had a 12v battery and an alternator. All was good until I cranked it over a little longer than usual and the starter brush holders smoked away. I got the starter rebuilt and converted to 12v. approx $150.

In another case, I blew up the 12v battery. I think it was because I used the car to charge the battery without driving it and the hydrogen built up under under the floorboards.

The wiring was modified by an amateur and had a 30 amp inline fuse in the alternator output wire. The fuse blew and I temporarily wrapped tinfoil around it and it melted the fuse holder. Funny what 60 amps can do to a 30 amp fuse holder.

Lastly, even with the smaller pulley installed the engine must be reved up before it will start charging.

If a standard alternator is used it is + to alternator and - to ground and change the coil polarity.

I'm not sure about the horn because I haven't gotten to it yet, but don't lay on it.

[Kevin in NJ]

Consider if you will how you used to tighten the alternator belt.

The general rule of thumb that I was taught was if you could move the alt pulley with your thumb the belt was not tight enough.

My brother went to a tech school (Kurt in NJ) and he tighten up a belt with the correct tension tester that no shop ever used. The belt was even tighter, like a guitar string.

We all know that a slightly loose belt on our older cars would allow the alt to slip and the belt would squeal. You would not get full output.

Also consider the belt and pulley. The belt always had a pretty good wrap around the pulley.

So on the A we have a smaller diameter pulley and less belt contact area. I have yet to see a belt tight enough a lesser finger than the thumb could not easily push the pulley around. In more than one case you could spin the pulley. So we know none of those installations could hope to come close to seeing the 60 amps the alt is rated at and one would wonder if it could really put out the same current that gen puts out in some installations.

The single wire alt will also very slowly drain your battery. There is always a slight current draw so you have to be careful.

Just some things to consider.

[Mike V. Florida]

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Unless you are running items that have a high current draw, a generator will work fine. You will read about problems with alternators as well as generators on the forum. Neither will work forever and neither will fail sooner than the other.

[DR]

6 volt alternator, is what I would be hooking up for now. So the starter should be connected to the negative post on the battery? I think it was hooked up wrong and that is what happened to the generator without having knowledge of it. It was charging fine last year and would always constantly charge. I thought it was doing the proper job but obviously it should charge but also be at 0 on the amp meter at times I think anyway?

[Charlie Stephens]

Originally Posted by DR

6 volt alternator, is what I would be hooking up for now. So the starter should be connected to the negative post on the battery? I think it was hooked up wrong and that is what happened to the generator without having knowledge of it. It was charging fine last year and would always constantly charge. I thought it was doing the proper job but obviously it should charge but also be at 0 on the amp meter at times I think anyway?

The charge only goes to zero with the car running when you have a regulator (used with later generator or alternator). With a cutout (original) you just boil water out of the battery. The car is positive ground so the negative battery cable should be connected to the starter. Is your alternator positive or negative ground? Hook it up backwards and it is ruined.


Charlie Stephens

[Mike V. Florida]

Is the Alt 6 volt positive or neg? is it one wire, two or three?

The amp meter will be at 0 when the alt is supplying the voltage that the car is using. Any excess will go to the battery, (amp meter showing charge) and more needed will come from the battery (amp meter showing discharge).

[Milton]

Another way to burn out a generator is to move the third brush for max charge. Did you check the gen? It's easy, just remove the belt and jumper past the cutout, and the gen will act like a motor and spin. As mentioned by others, the gens are quite reliable if adjusted correctly.

If you are using a stock charging system, i.e. 6v positive ground, then + to ground, - to starter with a wire from the starter to the T-box thru the amp guage and back to the T-box (other side) and to the gen cut out.

[DR]

Okay I ordered a 6 volt alternator for now it can be positive or negative ground it depends on how I hook it up. So I will need to connect the cable to the starter from the negative post on the battery so would this make it a positive ground system like it should be? The other cable goes to the transmission and the positive terminal on the battery. So this is how it should be originally? I hope this is correct? I will search for a generator as well later on I just want to get the car up and running again. Will the amp meter still function the same way as when the generator was working?

[Tom Wesenberg]

You can use a volt meter to see if the generator is putting out more than battery voltage, or if you don't have a volt meter handy, just shine you lights on the wall and see if they dim a bit as you turn the key off. If they do then the generator is working. You can substitute the dreaded A********* word for generator.

Originally the positive ground strap was bolted to the center crossmember, but some people like to bolt it to the tranny or run an additional cable to the tranny for a more positive current flow for the starter. I've never had a problem with the completely original charging system, except I added my electronic voltage regulator inisde the generator to replace the adjustable third brush. This way the battery is never overcharged or undercharged.

[Tom Endy]

An alternator on a Model A is much kinder to the battery than is the original generator set up. The Model A system was designed before regulators were used. The Model A generator will continue to crank out charging current to the battery regardless if it needs it or not, and can overcharge it, boiling out the water and overheating it.

In the old day people traveling cross country would run during the day with their head lights on trying to divert some of the charging current.

People who drove a lot at night generally had their batteries undercharged most of the time. Batteries like to be at full charge all the time. An alternator will do that for you as it has a regulator circuit that is constantly looking at the battery and determining how much charging current to send to it.

I have alternators on both my cars and on a long trip the ammeters are sitting at zero most of the time indicating the battery is fully charged and does not want any more current.

Tom Endy

[DR]

Thank you everyone for all your input. It is greatly appreciated have a a great Easter.

[Milton]

Excellent point Tom. With an alternator you also have a clue about the battery condition.

[Tom Wesenberg]

Here is a picture of the amp guage showing how it stays all the time the engine is running, except for the first 2 or 3 minutes when it reads about 6 to 8 amps while the battery is being recharged from starting. This picture was taken with my engine at idle. As Tom mentioned when you have a regulator it is a big help for the battery. I'm still using the same 6 volt battery I bought from a recycling yard 6 or 7 years ago. I've never used a battery tender on it, and never had to add water. It sets untouched for 6 months over Minnesota winters, and fires right up in the spring. The second picture shows the electronic voltage regulator in my 3 brush powerhouse. It takes about 5 minutes to remove the third brush and screw in the EVR. Another benefit of the EVR is less drag on the belt and engine, because the generator isn't working any harder than needed by overcharging the battery.

[ratamahata]

look in the Mike´s catalog in the section Alternator exists some info about the generators and the alternators...

[Lefty W.]

Originally Posted by Tom Wesenberg

The second picture shows the electronic voltage regulator in my 3 brush powerhouse. It takes about 5 minutes to remove the third brush and screw in the EVR. Another benefit of the EVR is less drag on the belt and engine, because the generator isn't working any harder than needed by overcharging the battery.

Hello, Tom. I'm new to the site. Could you tell me which vendors sell this EVR? Seems like a good alternative (no pun intended) to replacing a generator with an alternator.

[Lefty W.]

Originally Posted by Lefty W.

Hello, Tom. I'm new to the site. Could you tell me which vendors sell this EVR? Seems like a good alternative (no pun intended) to replacing a generator with an alternator.

Actually, I found a solid-state cut-out with a voltage regulator built in it:

http://www.funprojects.com/products/10505r.cfm

Has anyone used one of these?

[Tom Endy]

Originally Posted by Milton

Excellent point Tom. With an alternator you also have a clue about the battery condition.

A few years ago I had a bad cell in a battery. On a long trip I noticed that the ammeter did not want to return to zero. I wasn't smart enough to understand the ammeter was trying to tell something was wrong with the battery.

Tom Endy