Model A - 12 volt question

[1bali-rod]

hello guys.
i just though i would take this one to the experts.

I want to run a stock 4cyl. model a coupe 12 volt.
wondering what is all involved. Parts to change.

thans in advance
Bali-rod
Andy

[Steves46]

From what I understand, Les Andrews Model A Mechanics Handbook Vol II is an excellent source of information for modifications like this.
https://mafca.com/cart/index.php?productID=167

[Patrick L.]

There is not much involved. I'll assume you want to switch to + grd. Just install battery as such, change bulbs to 12v, install 12v 3 ohm coil and reverse leads [ points wired as battery grd], polarize generator.

[Sparky]

As a minimum (assuming you are keeping positive ground):
Replace 6V light bulbs with 12V bulbs
12V coil or dropping resistor on 6V coil
Dropping resistor for 6V horn
12V cutout for generator
Modern bendix on starter if not modifying the coils
Stock starter and generator will work on 12V system; if switching to negative ground, generator must be re-polarized, and wires reversed on ammeter and coil

Options:
12V alternator
Install 12V coils on starter
Install 12V coils on generator

FWIW, I run a 12V neg ground system with a stock generator and starter, and a solid-state "Fun Projects" regulator in place of the cutout.

[The Master Cylinder]

Originally Posted by Patrick L.

There is not much involved. I'll assume you want to switch to + grd. Just install battery as such, change bulbs to 12v, install 12v 3 ohm coil and reverse leads [ points wired as battery grd], polarize generator.

I assume you meant "Switch to '-' ground" as a stock Model A is already '+' ground?

[30 Closed Cab PU]

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Also dropping resistor on wiper motor if running DC wiper?

[1bali-rod]

No wiper motor, No horn
pretty much basic running ignition and lights,.

thanks all

[Smitty]

I am running 12-v in my coupe. Change out coil, bulbs, and while a 6 volt starter will work it slams pretty hard. Mine eventually took its tool on starter drives both modern and original. I am now running a starter re-wired for 12 volts and works a lot better. Converted to 12-v negative ground (need to make ammeter wire switch in the dash) and added resistor to horn. Everything is fine now, car runs a lot better and lights are a lot brighter. I run a 12-v alternator (1-wire type) which is available cheap in any auto parts store. Just need to change-out the pulley.
Steve

[Patrick L.]

Originally Posted by The Master Cylinder

I assume you meant "Switch to '-' ground" as a stock Model A is already '+' ground?

Ooopps, glad someone caught that !

[The Master Cylinder]

Originally Posted by Patrick L.

Ooopps, glad someone caught that !

HAH!! We're all confused enough without adding to the confusion.

[Bill G]

If stock 4-cyl, why change from 6 volt? Are you planning on having accessories? I once considered it, but all things considered, the changes neded didn't seem to get me much in the end. Sure, pretty easy and well covered in the Les Andrews Vol II book, and no wiring changes needed per se. However the need for voltage dropping resistors on the horn and coil, changes to the generator (or alternator) plus concern over the starter Bendix all led me to put my $ on other aspects of restoration. However, not only is it covered well in the Les Andrews book, a series of well crafted searches on the forum would give you not only the information, but hundreds of differing opinions on just about every aspect of the topic.

[Tom Wesenberg]

Only need to change one thing..............and that's your mind. It works great on 6 volts.

[Smitty]

I have CB radio hidden under the dash and a power outlet for GPS or charging my phone. Wife and I travel a lot in the coupe and the CB is for when we are traveling with the Model A club.

[Mike V. Florida]

This is from Ken at Kens Garage.


Battery

Any good 12 Volt battery will do as long as it will fit your battery box and hold down. I selected a 72 month, 675 cranking amp, universal battery.
Generator

I installed a GM 63 Amp Alternator with an internal self exciting voltage regulator. The hook up is one wire, the same as the existing generator. You will need to make two small brackets to mount the alternator or you can use two shackle bars and drill out for the proper size bolts. An alternator pulley can be purchased from your friendly Model A parts supplier.
Starter

No modifications are necessary to the starter. Just touch the pedal and enjoy really fast starts.
Ammeter

I changed the standard 20 amp ammeter to a 30 amp ammeter as an alternator will peg the standard meter. You must reverse the leads on the ammeter due to the change in polarity of the battery. Your neighborhood Model A parts supplier carries the 30 amp ammeter.
Headlights

Since I installed an alternator I opted to go all the way for headlights and convert to Halogen bulbs. The conversion is relatively easy. You can purchase a kit to modify your existing reflectors or you can purchase new reflectors with the Halogen sockets installed. You must install an alternator to successfully operate Halogen bulbs.
6 Volt kits are available. What a pleasure to be able to really see while driving at night.
Ignition

You could install a 12 volt coil and a resistor to reduce the voltage to the points.
I elected to install a PerTronix IGNITOR electronic ignition system. This is an extremely easy system to install as it fits entirely inside the distributor; no outside boxes are required. Kits are available for the standard Model A or B, early V8, and Mallory distributors. Both 6 and 12 kits are available.
Kits are furnished with a new coil as the correct coil resistance is very important for proper operation. Kits are distributed by: Remund Ignitions, Inc.
P.O. Box 857
Lemon Grove, CA 91946-0857
(619)460-3620
Horn

Getting the horn to work properly was the most perplexing part of the conversion. I tried several "voltage reducers" from the local parts stores but none could handle the current demands of the Model A horn. I finally purchased a 0 to 2 Ohm variable power resistor with a 100 watt rating from an electronics supply house. I selected a variable resistor in order to optimize the voltage to the horn.
The resistor I purchased was am Ohmite D100K2RO ($15.87) with two Type 12 brackets ($0.55 ea.) (Newark stock nos. 13F671 & (2) 13F099) from:
Newark Electronics
1-800-463-9275
Branch offices of Newark are located throughout the United States. Minimum order is $25.00. An alternate approach would be to puchase a 12 volt horn.
Light Bulbs

The following bulbs can be used with a 12 volt system: Cowl, Tail, and Dash Lights - #89, 6 cp
Dome Light - #67/97, 4 cp
Stop Lights - #1156/10, 32 cp
Turn Signals

If you have a Signal-Stat turn signal it will be necessary to change the flasher to a Signal-Stat #180 and the bulb to a #1445.

[Railcarmover]

if you have the coin run LED instead of halogen,amperage requirement is way lower..gotta run 12v,how else is the old bag gonna charge her phone?..

[Tom Wesenberg]

Originally Posted by Railcarmover

if you have the coin run LED instead of halogen,amperage requirement is way lower..gotta run 12v,how else is the old bag gonna charge her phone?..

Cell phones and GPS run on 5 volts, so they stay charged fine on my 6 volt socket in my Model A and 1950 Studebakers with 6 volt positive ground.

[jm29henry]

If it isn’t broke then don’t fix it!, my opinion Henry made it over 90 years ago leave it !you could get a inverter or I Bert’s has a device for your cell phone

[Purdy Swoft]

We know that six volts will work . For a dependable driver car , six volts is a bare get by . Though I have run model A's nearly sixty years on six volts , I very much prefer twelve volts . I don't change mine to run a bunch of electrical accessories . Twelve volt electrical systems have pretty much been standard equipment for the industry for over sixty years. Twelve volt batteries are readily available at most places and less expensive than six volt batteries in many cases . A slightly weak six volt battery usually won't have the power to run the starter and fire the ignition . Twelve volt batteries seem to charge quicker and take more time to get run down . Though mine crank OK on six volts , if well charged , I prefer the quicker turning of the starter on twelve volts . Twelve volt components are generally easier to locate on the road . The original unmodified generator Has worked for many years for me on twelve volts . I have from time to time run an original cutout on twelve volts .The system charges in amps and doesn't seem to know the difference . I do prefer and use the Fun Projects can style voltage regulator . The Fun Projects voltage regulator mounts to the generator exactly the same as the cutout , without any modifications . The Fun Projects regulator can be ordered in positive or negative ground . I've never had a problem with the unmodified starter when used on twelve volts . Worn starter drives and flywheel ring gears will fail easier on 12 volts . While a six volt coil will work on twelve volts I prefer changing to a three OHM coil than using a resister . I don't like the clutter and heat caused by the use of a ballast resister at the coil connections . I'm not trying to convince anybody to do Anything . This is just my preference and some of the reasons why .

[burner31]

Originally Posted by Smitty

I have CB radio hidden under the dash and a power outlet for GPS or charging my phone. Wife and I travel a lot in the coupe and the CB is for when we are traveling with the Model A club.

I can charge my phones and run a GPS on my 6V system, cost me under $10 to set-up, don't pay big bucks at a vendor when you can get all that's needed at wally-mart, for under $10.
Not sure about a CB set-up.

[CWPASADENA]

Originally Posted by Tom Wesenberg

Only need to change one thing..............and that's your mind. It works great on 6 volts.

I absolutely agree,


If the electrical system is in good condition, the original 6 volt system works very well.


All my Model A's and early V-8s are still running 6 Volt systems. Very reliable.


An electrical system in poor condition will cause problems regardless of the battery voltage.


Just my opinion,


Chris