6 volt vs. 12 volt

crumbaa

crumbaa

Member
I am sorry if this thread is duplicated. Once I was on the model A forum I could not find a way to search existing threads. I am doing a full frame up retortion of my grandfathers 1930 Cabriolet (68B). Not looking to have a concourse judging car just a very nice looking "like" original car. My dad clearly remembers that they used to keep an 8 volt battery with them in the car because there were times when the 6 volt would just not turn it over enough to start it. Is this a common issues? Is it a good idea to convert to a 12 volt negative ground electrical systems with an alternator that looks like the old generator? Anyone have any pros and cons of the 12 and 6 volt systems?

Any advice you can offer is greatly appreciated.

/Tony
 
This'll open up that can of worms. I'm a fan of 6 volts. As long as everything is in decent shape, its just fine. But, then again, I also like keeping the generator. Just call me crazy.
 
6v in good shape is good enough. I like the Generator as well. There is room to improve it with a voltage regulator. But 6 volts will do the job and is ample to start it every time provided the timing, plugs etc are up to par.

Do a search by clicking on the "Search this a Forum" link in the red bar on the home page of this forum.
 
The 8 volt battery overcomes a lot of bad connections.

Overtime the electrical path on the A can have problems. The ground path is the most odd. The frame is not directly connected to the engine through the engine mounts. So the connection relies on engine pans and the circuit through the front and rear axles.

Between paint and "improvements" like rubber shackle bushings, float a motor, and a rubber wishbone ball you loose paths.

There are also issues with getting the starter up 100% and other possible mechanical issues.

So the key is to make sure you have a good solid connection, everywhere.

Keep in mind the Model A as Henry built it was known for being very reliable and quite capable of running 60 MPH all day long. Properly rebuilt today (not to JS) you should expect the same.
 
6 volts and a generator have never failed me. In fact the car I can remember having the best lights is my 1950 Studebaker, When I would drive it across the west Texas desert it would really light things up. My 28 Model A with stock lights and a 6 volt battery is also fine for night driving, and good starting.
 
Either will work fine. Unless you are planing to use 12 volt accessories there is no NEED to go to 12 volts.

There is no reason why the 6 volt should not turn the car over, so the 8 volt is not necessary and would only shorten bulb life.

Properly restored components will work just fine with 6 volts.

Bottom line some swear by 6 volts some swear by 12 volts, it's your car.

I like original 6 volts.
 
After over fifty years with model A's, here is my opinion. Before anybody gets the wrong idea, I'm not saying and have never said that it is necessary to convert to twelve volt. Six volt is a bare get by, if everything is right it will work. If a person has a model A that functions up too their expectations on six volt, I would leave good enough alone. Most of mine are still six volt for that reason.

Twelve volt has been standard for the industry for nearly sixty years. With a ground up restoration, it is a very simple thing to convert to a superior twelve volt system and really doesn't cost any more. The original generator and starter works great on twelve volt with NO modification. Actually the twelve volt system will operate at about half the amps and will be easier on the generator. I use the Fun Projects can style voltage regulator . The original style wiring harness works great on twelve volts and no wires need to be changed as long as it remains positive ground. The original coil or a replacement six volt coil will still work but will require the use of a ballast resistor. I use a 3.0 ohm coil that is internally resisted. The original 20 amp ammeter will work good with most twelve volt conversions.

The advantage of this type conversion is there is no visible change, you get best of both worlds. If a person ever wanted to go back to six volt, the biggest thing would be the battery and bulbs.
 
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I have toured with both 6 volt and 12 volt. Your decision is what do you plan on doing with the car. Is this a casual use, drive to the coffee shop or ice cream store every now and then, get out with the local club once a month for a local drive or will you be doing some long distance travel. Once that question is answered then you can decide on other items. But the long distance tends to lead you to 12 volt since you can charge cell phones, cameras, run a stereo etc. with the 12 volt alternator. But if the other direction then keep it 6 volt. You can get battery tenders for either and keep the battery up between outings and have a fun Model A to run around in.

My roadster pickup is 12 volt as is the sedan. Both have heated seats, stereo and the sedan has A/C but that is my choice because I cover some serious miles on the Summer Tour some where around 5000 miles in a month of travel.
 

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Thank you all for the great information. What great source for advice and talk about experience, there looks to be tons of here. I think Kevin in NJ hit in the issue my Grandpa was fighting. When I was tearing the car down it was evident that someone attempted to do some restoration work including wiring, ad it was in pretty bad shape. Would it make since to install a strap from the engine to the frame to insure a good connection?
 
John LaVoy said:
I have toured with both 6 volt and 12 volt. Your decision is what do you plan on doing with the car. Is this a casual use, drive to the coffee shop or ice cream store every now and then, get out with the local club once a month for a local drive or will you be doing some long distance travel. Once that question is answered then you can decide on other items. But the long distance tends to lead you to 12 volt since you can charge cell phones, cameras, run a stereo etc. with the 12 volt alternator. But if the other direction then keep it 6 volt. You can get battery tenders for either and keep the battery up between outings and have a fun Model A to run around in.

My roadster pickup is 12 volt as is the sedan. Both have heated seats, stereo and the sedan has A/C but that is my choice because I cover some serious miles on the Summer Tour some where around 5000 miles in a month of travel.
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I am interested in a 12 volt negative system for the options it presents in accessories and in lighting choices. Is there any step by step list or book that would have all the steps and parts required?
 
My grandpa used 6 bolts for 62 years, and he liked it. I think he more or less kept it just because. He used a 6 volt alternator and a 12 volt converter for a cb, so I never really understood why he never just converted to full 12 volts all the way around. But anyways, 6 volts works fine. Now we have 12 volt on every car, and I put 12 volts on everything that I build. But that's because I'm going to drive mine, they are never ever ever going to put into judging, and I also now run a/c in the closed cars. I like the fact that with 12 volts you can power just about any electral Device that you want. I know some people say it won't give you any brighter lights, but I'm not convinced about that statement. I had problems for years getting my brake lights to shine bright. I had all the grounds clean, and a designated ground wire for each individual brake light and they were still dull on 6 volt. As soon as I changed to 12 they just brightened right up. It was amazing to see the difference. But my coupe is the only one I've had that problem on. Headlights are about the same, but I also had halogen bulbs for the 6 volt also. But to each their own, I like 12 volt but I'm not going to say it is a Must. It's just a good alternative if you decide to do anything other than 6 volt.... Or if you're tired of the battery running down on you.
 
chopo said:
how does the original generator charge a 12 volt battery?
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An alternator isn't necessary to run twelve volts on the model A.
The completely stock original model A generator will charge whatever battery that is used, up to 40 volts. Twelve volts will give quick starts with power to spare. A slightly weak six volt battery won't have enough power to turn the starter and fire the points at the same time. Many times a weak six volt battery that will still turn the starter but not start the engine will confuse the person in to thinking that they have a bad coil, condenser, or other electrical problems. Six volt is a bare get by that will work if the battery is well charged and everything else is just right. Most are not just right and the owner isn't capeable of making it just right.

I grew up when cars were mostly six volt. It was very common for cars to have to be push started in cold weather or if mistakes were made when trying to start the engine. Cars in the day mostly had hand chokes and were easily flooded, especially with a weak electrical system. Headlights also tend to be dimmer on six volt unless the reflectors are correctly shaped with correct plateing. This all pertains to the model A !!!

Converting to 12 volt with the stock generator is a very simple task. As long as the battery is connected positive ground, none of the original style wiring needs to be changed. An original cut out will work. I prefer voltage regulation and use the Fun Projects 12 volt positive ground voltage regulator. At least two other voltage regulators are offered by others but still require the use of the cut out.The Fun Projects can style voltage regulator takes the place of the cut out and looks just like the early cut out. The six volt coil can be used with a resister. I prefer the more powerful 3.0 OHM coil that is internally resisted. The Pertronix Flame Thrower coil looks similar to other replacement coils but gives electronic like performance with the original points distributor, without the module that often renders electronic ignition usless when it fails.
 
And, if for some reason you decide on negative ground, its just a matter of polarizing/flashing the generator and reconnecting the coil polarity to match that of the battery. Whatever the battery ground is, so should the points ground be. You'll also have to probably flop the wires on the ammeter. Whatever you decide, its important to only feed the points 6-8 volts.
 
Marshall57 said:
I am interested in a 12 volt negative system for the options it presents in accessories and in lighting choices. Is there any step by step list or book that would have all the steps and parts required?
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If lots of accessories and the very best brightest headlights are used, You will need to use an alternator. Being as I've got A Brattons catalog handy I will give recommendations and part numbers. I recommend the 12 volt 60 amp alternator that will support 60 watt halogen bulbs at idle. Page 65 part number 14960 price $185.00 .This is a one wire hook up alternator that operates on negative ground and will power all accessories. I recommend the Quartz halogen kit that is complete with reflectors and everything that you will need. This kit uses 60/55 watt bulbs that are focused and are just as bright as modern cars. Page 79 part number 17850 price $97.00. I use a 3.0 OHM coil that is internally resisted. The original style wiring harness works great. When converting to negative ground, the wires need to be switched at the ammeter and at the coil. The rest is just common sense stuff. Connect the 12 volt battery negative ground Replace all other bulbs with 12 volt, I use 10 candle power tail lamp bulbs but more powerful halogen bulbs are available in most model A parts catalogs. The 6 volt horn will need a resistor. I have used the original starter on twelve volt on many applications for 50 years with no problems. Some prefer to spend the money to have the starter converted with different field coils. The 12 volt field coils are an expensive mod that usually requires an electric shop to perform. It slows the starter and is a waste of money in my opinion. If the flywheel ring gear and starter drive is in good condition, the unmodified starter works good for me on 12 volt.
 
Yeah, the price is steep, I just used Brattons as a reference. There are many sources for a one wire 60 amp alternator. The last 60 amp alternator that I bought was from Dave Wilton in Paridise , California in the mid ninties. It has powered the 60/55 watt halogen kit from Bratton in the coupe for over 18 years.
 
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