alternator required with conversion to 12 volts?

I am looking at a C that the owner has converted to 12 volts.  He left the original generator on and says that it will charge just fine.  Is this correct?  It believe the coil needs to be changed as well.  Any thoughts?

If its Mag fired, and there's no other accessories on the Tractor such as headlights, tail, work lamp, etc., the Gennie might keep the Battery just with enough reserve to start it. If you have other accessories that you will be using, or its a Battery Ignition, (which it sounds like if you're talking a coil) the 6V Gennie will not keep the Battery up and the system satisfied with accessory circuitry in operation. When looking at coils with a 12V conversion and 4 cylinder engine, you need 2.7-3.3 ohms of resistance in the Ignition circuit for the engine to run correctly and not eat up the points. A 3.0 ohm coil with built-in resistor is what you want for that application. Universal 12V coils usually are only 1.5 ohms. You need a 3.0 ohm coil to do the job. We have em' in stock, or you can buy one locally at an Auto Parts store. If you go with an Alternator, the 10SI is the most popular. Changing the Ammeter to a Voltmeter would be a good upgrade also for safety. DO NOT use the OEM 3 position switch if so equipped. They do not like the fast moving current of 12V's. Use an aftermarket fused push/pull sw. to control lighting circuits. Other upgrades would include an Ignition sw. and in-line diode to control back feed. HTH If you need any more info, just give a call. Be happy to help you out.....

I could see that coming a mile away with my eyes shut. LOL

Sometimes a 6 volt will do 12 with just 12 on the fields, but usually the field poles saturate closer to 12 than 12, then it takes more speed to get 12. And running 12 volts on the 6 volt fields doubles the field current which is why the regulator points don't often last.

Gerald J.

The easiest alternator to use is what they call a one wire. Late 60s early 70s GM. Any good Napa man will know when you ask.

All you need to do is change light blubs and put a resisitor in front of the coil. Have ran many tractors like that . My WC probably 40 years and it is still going.

A one wire alternator will charge on a tractor. Ya just use a different pulley. I used the pulley that was on the old generator. Its been on a 52 CA for twenty years, don't tell me it wont charge. I know it will.

This is the pulley I use on the single wire alternators.
2 1/2 inch.
Comes with a special nut you will need.
Gives the alternator more rpms.

Did I ever tell you I'm nuts!!!!!

No, He just has Anxiety Lepidopterophobia.

It's a butterfly thing.

You gotta love it.

I'm not here to argue the dynamics of electricity. All I know is the old pulley will work fine and doesn't cost anything. Ask yourself one question. Did you have to goose your late 60s or early 70s automobile to get it to charge? I can start my tractor at idle and it will charge, no goosing, no running to a store for a pulley, it just sits there and idles while it charges. I was merely passing along information to make it simple. Apparently that's not good enough for some.

Have a nice tall glass of iced tea and cool off.
It's hot outside.

I have used the Mopar one from the 70's cars.
Get them at Napa.
Also a 4 post starter solenoid that will bypass the resistor for a full 12 volts while starting the engine.

Have most of the tractors with the newer 12 volt coils that has the right internal resistance so you don't need the ballast resistor.