12 volt conversion question

Brett Ritter

Brett Ritter

Junior Member
I know there is a 1 wire 12 volt alternator conversion, but I have a lot of other things I’d like to do 1st. On my Model T I was able to just switch the regulator, battery & bulbs. Is there a similar version of this for the A?


Sent from my iPhone using Tapatalk
 
Do you mean to add a 12V regulator (or cutout) to the stock generator? Yes, it works fine.
 
I am running two of my model A's on 12 volt positive ground with the unmodified generator . As long as it remains positive ground , the only parts that I replaced was the coil and installed the 12 volt Fun Projects voltage regulator in place of the cut out . I adjusted the third brush in the generator for a 10 amp maximum charge rate . The maker of the Fun Projects voltage regulator told me that being as the voltage was regulated I could up the charge rate to 10 amps for better headlights with no problems . I used a 12 volt three OHM coil . The original 6 volt coil can be used if a resister is used at the coil connection . The Fun Projects voltage regulator replaces the cut out without modification to the generator . The can style voltage regulator looks just like the original cut out but gives voltage regulation similar to the modern vehiucles .

If for some reason a person wants to convert to negative ground it will be necessary to first connect the battery cables to the battery as negative ground . I swapped the wires behind the ammeter so it could show charge at the ammeter when the engine was running and the generator charging .
 
The generator will put out over 40 Volts if there is no load. The battery is the load and the limiting factor for the voltage output. You can use the same generator just change the battery to 12V, the coil or use a resistor, the bulbs and a dropping resistor in the horn. You can also change the polarity if you choose, but have to repolarize the generator, and reverse the wires on the coil. I am running a 12V negative ground system with just a 12V battery change, the coil wires reversed, new bulbs, the same cutout, but am working on an internal regulator or will get the Fun projects regulator. If you would like have a chart with all the bulbs for 6 and 12 Volts, plus a lot of other electrical information. If you would like the information, send me an email at jrelliott42@gmail.com
 
The last time that I checked , the internal voltage regulator is only available in the six volt version . I am using the Fun Projects can style 12 volt voltage regulator . The Fun projects voltage regulator bolts on in place of the cut out and that's all that there is to it . The generator doesn't need to be disassembled to install and use this part . The third brush still adjusts the charging rate and it looks completely original . Without a doubt , this is the easy way to go for voltage regulation on the original style model A generator when converting to a 12 volt system . . .
 
Last edited:
The regulator that I am working on fits inside the generator and adjusts the field current to set the amount of Voltage and Current like the regulators in the vehicles today. It measures the voltage at a remote point and limits the current into the fields of the alternator to try to maintain a voltage of 14.2 in the system. The Fun Projects regulator adjusts the voltage by limiting the Voltage going into the system, and converting the rest of the Voltage and current into heat. It possibly has a 7812 IC inside or a variable voltage IC attached to a heat sink. It does not limit the Voltage output of the generator by varying the field current.
 
jrelliott said:
The regulator that I am working on fits inside the generator and adjusts the field current to set the amount of Voltage and Current like the regulators in the vehicles today. It measures the voltage at a remote point and limits the current into the fields of the alternator to try to maintain a voltage of 14.2 in the system. The Fun Projects regulator adjusts the voltage by limiting the Voltage going into the system, and converting the rest of the Voltage and current into heat. It possibly has a 7812 IC inside or a variable voltage IC attached to a heat sink. It does not limit the Voltage output of the generator by varying the field current.
Click to expand...

That's good info jrelliott. Thanks for sharing. Altho I have a PowerGen 12v alternator, your info is good to know 'just in case' I need it down the road.

You mention an interal 12v regulator. Is this something you plan to sell in the future?
 
With any of these type modifications, its important to keep your battery & terminal connections in good shape. The fun projects stuff is sensitive to spikes if the connections get too crusty or open. The old 3-brush units are still limited in there output so add any further accessories with care and forethought. The system is basically designed to pull the lights and the horn and that's about it. A person needs an alternator if they want more electrical gadgets in there.
 
For folks who don’t understand about the cutout.
The cutout is a switch sitting on the generator, or any place, that closes, or turns on, whenever it gets electricity coming from the generator.
It doesn’t care if it is positive or negative electricity.
To polarize the generator just touch a wire or something metal to the wire going into the generator to the battery current for one second. As long as you see a spark.
Easy way is from front of cutout to rear of cutout. Pliers handles work good.
As said above, a generator doesn’t know voltage.
On a car that uses a voltage regulator you will need to charge the regulator to the same voltage as the battery.
My F1 has run 12 volts the last 10 years on a 6 volt generator and 12 volt regulator. And negative ground.. Ian using a 12 volt coil and bulbs though.
It’s never had a heater but I have one ready for it. I hope the fan is 12 volts.

I have found that if you leave the car 6 volts you will have far less trouble than if you try to keep the 12 volt battery up with a 6 volt generator running 12 volts.
 
I love my 6 volt positive ground alternator, turn the key mash on the floor ready to go. I use a inverter 6 to 12 to run radio or anything else that's 12volt. I guess it's how you use your car, all year like I do or once in awhile. All will work if used right.
 
I run some of our model A's with twelve volt positive ground . I prefer and mostly use the original unmodified generator with the Fun Projects voltage regulator . I adjust the third brush in the generator for a maximum charge rate of 10 amps for somewhat better lights . I like to use the Pertronix Flamethrower coil . I use the 12 volt three OHM version that doesn't require the use of a resister . The original style 6 volt coil can be used if a resister is used but the ignition will remain only six volt if the six volt coil is used . The spark comes from the coil . I prefer my twelve volt conversions include the ignition .

Some seldom drive at night . If brighter lights and a more powerful electrical system is needed , twelve volts and the use of an alternator is the best way to go .
 
Last edited:
I prefer to have people think I have 12 volt system--- fast cranking, bright light, not afraid of night driving, it's all in the details, proper restoration , not having painted surfaces in the electric path, tinning the frame where the ground strap attached-- no paint on generator bracket where it attached to the not painted there front cover, --- I soldered the heads of ammeter studs to the internal shunt(no more hot ammeter),used brass nuts, ---- terminal connections crimped and soldered, ---been very reliable most things haven't been touched since restoring them 45 years ago--though it is time to go through the generator again, it was the first one I ever rebuilt and I know better repairs now(for reliability comparison the alternator in my 74 chevy truck I have had for 40 years has been apart 3 times for internal parts failures--- reliability, bright lights, and fast cranking can be had with stock charging system if properly restored and adjusted to your use
 
You must log in or register to reply here.
Back
Top