Stupid electrical question 12v/6v

I just picked up a 47 CJ2A with a 225 V6 in it that a previous owner had swapped in. My stupid question is how do I know if it is 12 volt or six volt? The battery is smaller then a normal battery and there is a "12 volt to six volt reducer" thing on the firewall. It has the normal cable coming off of the starter solenoid and the other from the block. This is my first time messing with a Jeep that was once or is 6 volt. I am really contimplating putting a new wiring harness in it and be done. thanks

 

Do you have a digital voltmeter? If you can't tell by looking at the battery, measure it. Get a cheap meter at Radieux Shaque - you'll need it if you rewire.

 

And once you have it, you'll be amazed at how many things it is useful for.
Home Despot sells 'em too. Get one!

 

If it has a ballast resistor on the firewall there is a good chance it is 12V as I cannot imagine a 6V system needing it, but as said above a simple check with a meter would tell you. The ballast resistor drops the voltage to 6V for the coil, it is a little ceramic resistor.

Are the headlights and stuff in it? I believe they would be stamped 6V if it still was as well.

 

Mmm, pretty sure the ballast resistor is in there to limit current, not drop voltage. It does drop the voltage, but that's not its prime function. I'd expect it would be needed in either a 6 or 12 volt system.

 

yup, i use a ballast resistor in my flattie and it is converted to a 12v single wire alternator, but i also have a 12v coil in there.

 

Yes it is a ceramic reducer on the firewall. The headlights and everything is there, I will check those things and grab a meter, thanks guys.

 

I agree with everything said above. The Jeep was probably 6 volt to begin with and the swapped in motor/accessories 12v. That being said the voltage reducer on the firewall is to reduce voltage to things like gauges, lights, etc. Look at the gauges, frequently they are marked whether 12v or 6v. If not part #'s may help. Bulb #'s can be a giveaway too. If the previous owner were smart, he may have changed the bulbs to 12v units however.
One other thing, if you have a Harbor Freight nearby go there to get a meter. It's the same one Home Depot sells for about a 1/4 of the cost. Found this out the hard way after had to buy one for at home and had already purchased from HD. Nickmil

 

:iagree: most likely reducer is for the gauges etc

 

being a flatty prob the only gauge the reducer is for is the fuel,the rest were mechinical werent they? amp meter dosent matter does it as it reads amps not volts.

 

Simply put, Count the holes you can fill the battery with water and double it.

 

:iagree: count the # of cells in the bat. 3cells=6v 6cells=12v

 

I have a 1946 CJ2A with a 225 V6 and it is set up for 12 volts. If yours is the same engine it's either a Buick or Jeep engine. They were built between 1964 to 1972. In 1967 Willys bought the right from Buick to manufacture these engines. Then Buick bought it back in 1972 but increased the cu in when they started to build he 231 cu in V6. Never heard of one running off 6V. Lots of info on the web about these engines and folks doing engine swaps.
I did have a tractors that was 6v and the starter turn over the engine very slowly. Replaced the starter & battery to 12 v and it started good. Left everything else 6 volts but used a resistor to drop the voltage for the rest. But I doubt if your jeep is that way since the engine was set up for 12 v.