6V to 12V conversion
 

Good, bad, correct NOT the intention of this Post.


In the latest issue of Street Rodder magazine is a detailed (with pics) article on how to convert a stock 6V Model A to 12V. It may not be totally accurate but interesting IMO. FWIW
Paul in CT

Re: 6V to 12V conversion
 

I haven't read the article in Street rodder magazine . Converting the model A from six to twelve volts is really simple . The voltage of the battery that is used controls the voltage . To make things simple and appear original , I use the original unmodified generator with a Fun Projects TWELVE volt voltage regulator that mounts in place of the cut out with no mods needed for the generator. There is a difference between the six volt and the twelve volt Fun Projects voltage regulator . If the car will be used with positive ground , No mods to the original wiring will be necessary . The generator charges the battery in amps and I adjust the adjustable third brush in the generator for a maximum charge rate of ten amps . The voltage regulator allows the generator to charge on demand . In other words the generator won't charge maximum rate except when needed for the lights or other higher draw accessories . It will be necessary to either use a ballast resister at the coil or change the coil to a three OHM version for a more original look . I have run unmodified six volt model A starters on twelve volts for fifty years or more on some of my model A's with no problem . I have used GOOD original starter drives on twelve volt but it is probably best to use the modern starter drive . Old worn starter drives can fail on either six or twelve volts . Of course all of the bulbs plus the battery will need to be changed to twelve volt . Any six volt accessories will need a ballast resister . If a lot of high draw accessories are used it would be best to use an alternator . The alternator can charge higher amperage as needed with modern cars with higher draw accessories . Most of the model A parts catalogs list a one wire connection alternator to take the place of the generator .

Re: 6V to 12V conversion
 

12v conversion using an alternator means smooth constant voltage,your electrical components will last longer,the parts are cheaper and most modern conveniences are configured for 12v.For a touring car its hard to beat.

Re: 6V to 12V conversion
 

There are lot of us who have changed to 12V using the original generator and have had good results. The battery acts as a large capacitor smoothing out the impulses from the commutator of the generator. The alternator may produce a little smoother 12V, but do the other electrical components care?

Re: 6V to 12V conversion
 

The other components don't seem to know the difference or care . The generator should have an easier life on twelve volts and a lower maximum amperage output . I use the original type 20 amp ammeter . With this setup the maximum charge rate is set for a maximum 10 amp charge . I use the halogen headlight bulbs that fit the original sockets and they are plenty bright , with the generator brush set for a maximum charge rate of 10 amps . I use the 35/35 W 12 volt bulbs

Re: 6V to 12V conversion
 

12V with a negative ground is beneficial for employing modern electronic devices in a Model "A" such as a cell phone charging port, GPS and other devices using a USB port. I have a 12V accessory power panel in my "A" that is held in place with commercial Velcro.

Re: 6V to 12V conversion
 

To change the polarity from positive to negative ground it will be necessary to reverse the connections at the coil , ammeter and battery to negative ground . It will also be necessary to flash the cut out . I use a short piece of wire and use it to jump between the terminals on the cut out to flash the cut out and complete the change from positive ground to negative ground .

Re: 6V to 12V conversion
 

Which issue of Street Rodder. I looked through mine and could find the article you described (Aug, Sept, Oct)
Thanks Brian

Re: 6V to 12V conversion
 

November, starts on pg 68, came to me a few days ago.
Paul

Re: 6V to 12V conversion
 

Many folks may not know that a 12 volt system amp draw is half of a 6 volt. Since our wiring was gauged for 6 volts and twice the amperage you end up with a heavy duty wiring harness... For touring an Alternator does a great job and hallogen headlights and LED tail and turn you are ready for some wonderful evening cruises with you better half!

I also recommend a modern bedix There is a lot more torque hitting it on 12 volts which can shear bolts. Easy mod. buy only the US made one however.

Re: 6V to 12V conversion
 

I wrote the story using my '30 coupe as the guinea pig. What part did you find "not to be totally accurate"? Just hoping to clarify if something came across as vague.

Very happy with the 12 volt upgrade as well as the Pertronix conversion. The car fires right up, without using the choke, which was something it never did before. Bright lights, a reliable alternator, and I was able to move the battery under the seat. Win-win for me.

-Ryan

Re: 6V to 12V conversion
 

I am just wondering what would have made it so the choke would not be needed. Maybe when the weather turns cold again, you might find that it still needs to be choked.

Re: 6V to 12V conversion
 

less fluctuation with an alternator..I agree it looks funny,especially the japanese ones..

Re: 6V to 12V conversion
 

Surprised me as well. When I first bought the car, I drained the battery trying to start the car as it required a precise balance between choke, throttle, etc to get it to fire off. Eventually I figured out the required dance and could get it fired first crank.

Speculation says hotter spark and faster cranking is responsible. That's what I'm leaning towards. I completed the upgrade over the winter so warmer weather wasn't around to help.

Re: 6V to 12V conversion
 

I do not know what the fuss is. The car was designed for six volts. American cars were 6 volts for decades with no problem. My car remains six volts and it runs fine.

A bigger concern is fuses. I have wired my car for separate fuses on separate branches.

Re: 6V to 12V conversion
 

A twelve volt conversion is one of the best upgrades that can be made to the model A in my opinion .

Re: 6V to 12V conversion
 

While European cars were 12 volts from very early, even 24 volts, I am told. It took a LONG time for American manufacturers to get out of the 6 volt rut. Now that they have, can anybody imagine them going back to 6 volts?
IMO, this is like the discussion about oil and air filters. It is modern practice and won't be going away in a hurry because the benefits are too great.

Re: 6V to 12V conversion
 

I can't think of a single advantage for running any vehicle on six volts. Six volt systems run higher amps . Higher amps cause heat and shorter component life. Six volt systems have less cranking power , dimmer lights plus six volt parts and components are getting harder to find . Most cars have used twelve volts systems for over sixty years . There were several good reasons .

Re: 6V to 12V conversion
 

You may already know this, but here goes anyway.


There is at least one exception to this, the Model a Coil. The 12V Coil actually has to dissipate more power than the 6 V Coil. And some would rather use a 6v coil with the series R to keep coil power dissipation down.


6V Coil, 6 Volt battery - (Volts)6 V /(Resistance)1.5 ohms = (Current) 4 amps
(Current) 4 amps X (Voltage) 6 Volts = 24 (Watts, Power)


12V Coil, 12V battery - 12 Volts / 3 ohms = 4 amps
4 Amps X 12 Volts = 48 Watts


Even though the coil is not on 100% of the time, the 12v coil has to dissipate twice the power of a 6 Volt coil, which can shorten the life of a 12 V coil since it is in the same power dissipation package as the 6V coil.


On a 12 Volt system some use a 6V coil with a series resistor, and the power dissipation is then shared equally by the coil and the series resistor. This drops Coil Power dissipation to 24 Watts.

Re: 6V to 12V conversion
 

I run a three OHM coil on my twelve volt converted model A . I don't need or use a resister with coil .

Re: 6V to 12V conversion
 

Last time I checked a higher coil discharge means a hotter spark..means a more efficient burn,means a cooler engine..that isn't a bad thing.So many modern improvements can be made to make the model A a more enjoyable and more efficient machine..without swapping out the basic components..its one of the few engines I've seen where you can basically double the horsepower in a day..

Re: 6V to 12V conversion
 

"While European cars were 12 volt from very early . . .."

My 1965 Volkswagen was 6 volts. I think the 1966 was still 6 volts, although I did not own a 1966, so I am not certain.

W. Michael

Re: 6V to 12V conversion
 

I have a 1928 Delage - 12 volts as were several others pf that era. VW was the exception over there but they eventually saw the light too.

Re: 6V to 12V conversion
 

!966 were still 6 volt, they went to 12 volt system in 1967.

Re: 6V to 12V conversion
 

I do not plan to convert mine, everything works well at 6V. However, I also see there would be advantages to running 12v neg gnd if you wanted to add accessories. Mine'll stay as is, but I certainly am not going to poo poo those who do convert theirs. I would question those who do the conversion to fix a problem they are having, if a starter or generator or wiring etc isn't cutting it at 6V, it won't be long it won't be cutting it at 12 V either.

Re: 6V to 12V conversion
 

[QUOTE=eagle;1797472]I do not plan to convert mine, everything works well at 6V. However, I also see there would be advantages to running 12v neg gnd if you wanted to add accessories. Mine'll stay as is, but I certainly am not going to poo poo those who do convert theirs. I would question those who do the conversion to fix a problem they are having, if a starter or generator or wiring etc isn't cutting it at 6V, it won't be long it won't be cutting it at 12 V either.[/QUOTE


X2

Re: 6V to 12V conversion
 

I have a 1966 Porsche 912 (4 cylinder) that is 6 volts. The first year for the 911 (6 cylinder) was 1966 as well but I'm not sure if it's 6 or 12 volts.

David Serrano

Re: 6V to 12V conversion
 

I'm going to thread lightly here as I have just gotten my first "stock, non modified" early Ford. I have a couple of others, but they are V8, HotRodded and already converted to 12 volts. I have a stock 6volt, positive ground '30 coupe that I want to convert to 12 volts, and negative ground. I understand the 3ohm coil, that 6 volt wiring is compatible, need to change bulbs etc. what I don't understand is, if I change to negative ground, do I need to source a negative ground starter?? Won't the original positive ground one run reverse if it's hooked up on negative ground?? Maybe that was touched on, but I looked thru a couple of times but didn't see anything about that particular issue??
Thanks, Ken

Re: 6V to 12V conversion
 

And yes I've been a member/lurker here for info and learning since 2013, but that was my first post because most of my stuff is HotRods and I post those kind of things over on the HAMB.

Re: 6V to 12V conversion
 

No, the starter will turn in the same direction. They are not polarity sensitive. When I convert to 12v, I modify the starter so it doesn't kick as hard when it engages. The vendors have kits for that.

Re: 6V to 12V conversion
 

Synchro909, perfect, thank you!!