12 Volt

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Will
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12 Volt

Post by Will » Thu Nov 20, 2025 10:42 am

I have a friend that wants to switch his T over to 12V, Who sells a reliable 12v starter and alt.
As Tom Sellick told Marston in the movie Quigley Down Under, I told you I dont have much use for handguns, I never said I didn't know how to use them!


TXGOAT2
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Re: 12 Volt

Post by TXGOAT2 » Thu Nov 20, 2025 10:50 am

No magic in 12 volts.


speedytinc
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Re: 12 Volt

Post by speedytinc » Thu Nov 20, 2025 11:25 am

If you feel you must!
Admin jeff sells converted to 12V T starters. Its a PITA job. I have done a few also.

A model T generator will produce 12V. It dont know any better.
One must adjust the output to 1/2 for longevity purposes, 4-5 amps is plenty anyway.
That saves a few bucks, keeps a T motor looking like a T motor & avoids some common alt conversion failures.


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Re: 12 Volt

Post by Moxie26 » Thu Nov 20, 2025 12:46 pm

Will ... It will cost him a hell of a lot less simply to replace battery cables with the proper gauge, clean and shine all electrical connections, use a quality 6 volt battery, and even more important to have the generator working as designed with the current, no pun intended, voltage regulator offered.... If the starter is filthy, cleaning and new carbon brushes, maybe in order along with sealed bearings. ... PLUS... LED bulbs will give a hell of a lot more light with less drain on the battery and generator.

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Jeff
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Re: 12 Volt

Post by Jeff » Fri Nov 21, 2025 12:37 am

Just look at my website under 12v Starter conversions and you'll find a wealth of info and pics of horror stories of folks jamming 12v into 6v starters. Honestly, I try to talk folks OUT of converting their cars to 12v BEFORE they do it. If it's already done, then I do make 12v converted starters that work well and I must have sold over 100 of them at this point.... They're so popular I keep them in stock at all times. I've sold dozens on T-Bay and mostly through my website.

Unless 6v batteries are wildly expensive or unobtainable, there are zero justifiable reasons to convert a 6v car to 12v. A well maintained 6v car will start and run just as well as a 12v car. Design considerations are different for each, and if properly met, there's no difference.

Keep in mind 6v cars require larger wire for the starter circuit so more power can be delivered to the starter. Who knows what 100 years of owners have done to their cars in the name of "improving" them...
If you want to run 12v accessories on 6v, there are DC-DC boost converters that do the job well. I have one on my car.
Want brighter headlights? Buy 6v LED headlight bulbs from Langs. Game changer.

12v cars require ALL electrical components to be converted to 12v. Yes, you can run your coils on 12v.
The generator will be under a higher load and will need to be adjusted for lower output or you'll reduce its life significantly. A fully rebuilt generator with a rewound armature and new field coils are a good option. Old armatures & field coils develop shorts and fail completely or have reduced output.
The starter will need to be converted or eventually you'll destroy your ring gear AND your bendix.
All light bulbs will need to be replaced.
If you use an 12v alternator (or even a 6v alternator for that matter), the charge circuit wiring MUST be upgraded or you risk a car fire.

This is not an exhaustive list. There are other considerations.

As always, your mileage may vary.
Jeff
Last edited by Jeff on Fri Nov 21, 2025 10:31 am, edited 2 times in total.
"The trick to creativity is knowing how to hide your sources..." Albert Einstein
1921 Model T Touring, 1930 Model A Roadster
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Topic author
Will
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Re: 12 Volt

Post by Will » Fri Nov 21, 2025 7:34 am

Jeff, I have somewhere around 16 years of uninterrupted service of my Larry Becker 12V starter and alternator. I made the switch after 3 failed 6V batteries and two generator failures. As you mentioned I did have to replace all the wiring and lights. I'm all about keeping things as original as possible. Iv changed my 12V battery before coming to Florida and it been in there for 11 years. Of course I guess the difference might be the year round ability to drive the car down here versus putting it up for the winter months. I will try and see if I can find your set up on e bay, What is your e bay handle?
As Tom Sellick told Marston in the movie Quigley Down Under, I told you I dont have much use for handguns, I never said I didn't know how to use them!


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Re: 12 Volt

Post by TXGOAT2 » Fri Nov 21, 2025 9:41 am

I wonder if your 6V generator and battery troubles weren't related. (?)

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Re: 12 Volt

Post by Jeff » Fri Nov 21, 2025 10:36 am

TXGOAT2 wrote:
Fri Nov 21, 2025 9:41 am
I wonder if your 6V generator and battery troubles weren't related. (?)
If you don't have a voltage regulator (you still have a basic cutout) and you drive your car often, the battery will ALWAYS be overcharged leading to a failed battery. Overcharging is the #1 killer of batteries. Hence why we devised Model T voltage regulators! The T charging system works well, but there was never a provision for regulating it's output. Modern semiconductors were only first invented in the 1950's.

Jeff
"The trick to creativity is knowing how to hide your sources..." Albert Einstein
1921 Model T Touring, 1930 Model A Roadster
Voltage Regulators, Starter & Generator Repair & Parts manufacturing
www.modeltregulators.com
www.modeltstarters.com


TXGOAT2
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Re: 12 Volt

Post by TXGOAT2 » Fri Nov 21, 2025 11:09 am

A T generator can be modified to work with an old style voltage regulator. But those are becoming scarce and expensive. A solid state regulator can be expected to extend battery and bulb life. As late as 1936, Packard cars used a 3 brush generator and cutout. Seasonal adjustment of the 3rd brush was recommended. In 1937, the 120 models were equipped with a 2-element voltage regulator while retaining the 3 brush generator. Later cars used a 3 element regulator. I think Chrysler was the first to offer an alternator with an external, solid state regulator about 1963. By the mid-1970s, most alternators has internal solid state regulators. I have a 1981 Dodge W-250 that uses an external solid state regulator. Overcharging wrecks batteries, especially if the electrolyte level is allowed to get low, and overcharging will cause it to get low much oftener that it should.


TXGOAT2
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Re: 12 Volt

Post by TXGOAT2 » Fri Nov 21, 2025 11:14 am

I have 50 CP headlight bulbs, and if I turn them on, it pulls the ammeter down to zero at road speeds. It peaks at about 10 amps with them off and drops to about 4 amps with the battery charged at road speeds. I'm not clear on whether the generator output is zero when the ammeter indicates zero, or if it is charging at whatever rate the bulbs are consuming power, but not putting any current into the battery. If the latter, it is wasting some engine power and generator brush life, and using up the scarce headlight bulbs when not needed. A regulator would correct these problems and eliminate the need for the driver to use the lights to regulate battery charging.


TXGOAT2
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Re: 12 Volt

Post by TXGOAT2 » Fri Nov 21, 2025 11:15 am

Grounding the generator will bring output to zero, but using a resistive load to dump power would not. (?)

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Re: 12 Volt

Post by jsaylor » Fri Nov 21, 2025 7:06 pm

I converted to 12 volts some 35 years ago when I just couldn't find decent 6 volt batteries and issues with the T generator. . I also installed a late Ford Autolite generator modified to fit the T mount. These aren't being made any longer. When Larry Becker started selling his modified Delco 12 volt starters, I changed over to them in both cars. I have had very good luck with both. The only continuing issue That I have had with 12 volts is the bendix spring. I have broken and deformed many, even with the Becker 12 v starter. I now use Model A bendix springs. They are heavier and handle the 12 volts force much better. I do have to be careful with the two bolts that hold the spring on. I usually have to grind the heads down a bit to clear the cover. If I were to build up another starter T, I most likely would stay with 6 volts.

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Oldav8tor
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Re: 12 Volt

Post by Oldav8tor » Fri Nov 21, 2025 8:18 pm

My 1917 Touring was not built with a starter, generator, battery or electrical system. I decided to install a 12 volt system primarily because 12 volt accessories are readily available, 6 volts not so much. I started out with a rebuilt 6 volt starter but had problems, mostly with the Bendix. Five years ago I installed a WOSP LM256, geared starter designed for the Model T by the legendary Tuckett brothers of England. It is available from Snyders, pricey, (tariffs?) but in my opinion worth the cost. It's geared and the gear engages from the front, so it can be removed without damaging the magneto. I like the fact that it first engages the ring gear and then spins, which means less wear on the ring gear teeth.

I ran a 4 AWG copper cable direct from a compact Odyssey AGM battery under the back seat to the starter, not needing a foot switch because the starter has a built-in solenoid. I've mounted a key switch below the steering column. I ran a wire from the (+) terminal on the starter to a terminal block and distribute power from there. I've installed LED's in the headlights and LEDs in the Kerosene lamps plus a couple of magnetic mounted brake and turn signals. I'm able to keep the battery charged with the output of a Regan "Hot Shot" charger, which converts some of the output of the magneto to DC to charge the battery.

Each of us gets to choose what'll work best on our Model T's. I've been very happy with my choice of 12 volts.

WOSP LM256 Geared Starter
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Re: 12 Volt

Post by Jeff » Fri Nov 21, 2025 11:19 pm

Oldav8tor wrote:
Fri Nov 21, 2025 8:18 pm
Five years ago I installed a WOSP LM256,
It's exactly for this reason (among others) that I perfected my 12volt Model T starter conversions which use stock bendix parts (springs) without causing issues I've and priced them competitively. Thankfully the choice is now purely personal preference.

I for one, dislike seeing these and other modern appendages bolted onto Model T's.... but we live in a free country and to each his own. The good news is these are not destructive additions and can be easily reversed by those who wish to preserve authenticity.

"Necessity is the Mother of Invention" as they say.

Jeff
"The trick to creativity is knowing how to hide your sources..." Albert Einstein
1921 Model T Touring, 1930 Model A Roadster
Voltage Regulators, Starter & Generator Repair & Parts manufacturing
www.modeltregulators.com
www.modeltstarters.com

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