Generator vs Alternator
 

Disclaimer: I have never driven a model A. Currently working on a 1930 AA I want to drive and am in process of rebuilding generator.
Question: I have been reading and heard several folks comment that you HAVE to have an alternator if you’re going to use your headlights. I drove 50’s model trucks and Jeeps years ago with 6 volt generators and headlights and don’t remember having any problems. If the model A generator was that inadequate why did Henry bother putting the headlights on?

Re: Generator vs Alternator
 

I use a generator with a voltage regulator and original type headlights. Generator maintains battery well, and I have plenty of light at 45mph. If you plan on hopping up the A to go 55+ at night, then you may outdrive the headlight. Then go with an alternator and halogens.

Re: Generator vs Alternator
 

The only problem I see coming from using a generator with stock lights is if you will be doing a lot of night driving sitting in traffic. Once the generator cuts in to charge I see between 0-1A of charge with the lights on. I also use a regulator. I’m not sure how much an old Jeep generator can put out but the A is good for about 12A, maybe a little higher in short spurts.

Re: Generator vs Alternator
 

I don't remember what the Jeep's generator output was, but opposing traffic would often flash high beams at you while you were running low beams. I don't know if the lights were really that bright or just the fact that they were high up on the car and close together made them seem brighter. They always dimmed back when you gave them your high beams. You felt like you were flying at 45-50 mph in the Jeep so I don't remember outrunning my headlight beams! I really can't wait to get this old truck out on the road and back traffic up some!

Re: Generator vs Alternator
 

I drive a lot at night, I have 35 watt halogen headlights, with some ventilation the generator will make 14 amps long term--- I just didn't put the cover and on---first generator I rebuilt, ---45 years ago, been more reliable than the Chevrolet with alternator , that has been apart 3 times in 35 years, the same alternator that is used in most A conversions--- except for the pulley, the A conversion needs a small diameter pulley, this puts more strain on belt, has to be tighter too, less water pump life, less belt life--- with stock generator I am still using same belt 45 years though it's showing wear now, ---- the one wire alternator can have resting draw issues creating need for shutoff switch, and only Chinese rebuilding parts may have too high charge voltage issues
For me the generator is cheapest, I can buy and build one for under 10$

With a generator a dead battery can be push started, with alternator you will need a jump or battery charger

Re: Generator vs Alternator
 

The original headlights were equipped with 21/21 CP bulbs (high/low) - about 3 amps each. 50 CP bulbs pull about twice that, which with the other loads exceeds the rated capacity of the generator, 12 amps. Ford never approved bulbs over 32CP (~4A).

Re: Generator vs Alternator
 

The 50cp bulbs take more than the 35 watt halogens---to get good light with the 50 cp bulbs I would crank the 3rd brush to 18 amps

Ford considered it normal to have a discharge with headlights on, the charge rate is adjusted to give enough charge during daylight driving to make up for night use

Re: Generator vs Alternator
 

I have seen a picture demonstration of properly adjusted stock lights with nicely polished reflectors and they gave good view down the road. And my lights being out of focus looked like the bad picture but stated above. just scrub off ten miles an hour and your fine. I need to order some parts to fix up my adjusters.

Re: Generator vs Alternator
 

I don't see a problem using the 6v generator with 50/32 CP lites. If used quite a bit then you might want to bump up the out put to about 12 amps [ versus 2-4 for normal use]. [ I don't need to use high beams]
If an EVR is used then you don't have to worry about always messing with the 3rd brush.

Re: Generator vs Alternator
 

I just installed LogoLites LED headlight bulbs and a Fun Projects voltage regulator on the original generator, and I have plenty of bright light to drive by at night now. I did replace the original reflectors with new ones from Bratton’s, as the silver plating on the originals was disappearing. Currently draw with the LED headlight bulbs is less than 2 amps. I’m quite happy with this arrangement.

Re: Generator vs Alternator
 

Thanks guys for the input from experience. I want to keep the mechanics as original as possible for a driver. I know from my experience on the 40's & 50's vintage cars that the generators were VERY dependable long term.

Re: Generator vs Alternator
 

The one thing I will say about the A generator is that when you put on the front bearing make sure it presses on tight or use loctite. Seems like the bearings they sell don't fit tightly enough onto the armature shaft.

Re: Generator vs Alternator
 

Not true, with correctly (key word, correctly) restored headlights you will be fine.


I will admit that if you want to use modern accessories that use a lot of current, the alternator is the way to go.

Re: Generator vs Alternator
 

I have a generator with an internal EVR and it works very well.


I re-silvered my original reflectors and use 32/50 bulbs.


The lights are very good.


I have been playing with LED Bulbs and I am not completely happy bet they are getting better as I get the focus adjustment more correct.


My experience,


Chris W.

Re: Generator vs Alternator
 

How do you re-silver?

Re: Generator vs Alternator
 

Find someplace that does teapots and try them
Or buy new ones from brattons that have modern reflective material
If you are going to use regular bulbs look for old stock, there's no workmanship in modern ones I have seen, the filaments don't look like the placement the original ones have, this will affect focus
About 25 feet away without the lens the focus is adjusted to give a spot about basketball sized, if reflector is properly shaped, then with lens on you will get the best light it can do--- for me stop signs show up at .3 to a half mile away, and am comfortable driving at 50 on moonless nights

Re: Generator vs Alternator
 

When I got my first Model A as an adult more that 30 years ago the previous owner had installed halogen headlight bulbs. The car was a 30 town sedan with a 6-volt battery and generator. When I drove the car for the fist time at night I turned on the headlights and the ammeter needle slammed so hard against the negative peg it shook the whole car. The headlights were drawing way too much current. There was no way you could drive this car at night for any length of time without running the battery down. I soon replaced the bulbs with standard 6-volt bulbs.

Today my Victoria is still a 6-volt animal, but with a positive ground alternator. I ran standard bulbs in the headlights for years until recently when I installed the new LED bulbs. I am very pleased with them.

I believe it is best to run an alternator as it provides all the power output that is needed to operate anything electrical on a Model A. The regulator circuit also provides that the battery always remains fully charge. The battery will last longer when it is always fully charged.

Tom Endy

Re: Generator vs Alternator
 

Generator will work just fine.

Re: Generator vs Alternator
 

I’m a little funny. Alternator just doesn’t look like it belongs on an A.

Re: Generator vs Alternator
 

Agreed. The thing I always wonder about is why no one has tried to make an alternator that looks like the stock generator. Many other old cars have this upgrade available.