6 volt positive ground
 

I am sure it has been covered but can some one school me on this ? Will be 6 volt in my 32 pickup with a 59A flathead and a pre 39 generator so do I need to have positive ground or can it be negative ground ? Also, have an original amp gauge and does it require positive ground? Can not wrap my head around the concept 🤔

Re: 6 volt positive ground
 

Make it + ground and then your wiring diagram will be correct. Why change things?

Re: 6 volt positive ground
 

Positive and negative ground will both work. The real question is why change it and confuse those that work on the car? If you go to negative ground the you will need to reverse the wires on the back of the ammeter as it only measures the flow of electrons. You will also need to reverse the wires on the coil. The starter motor will spin the same way with either positive or negative ground. You need to polarize the generator for the negative ground.

Charlie Stephens

Re: 6 volt positive ground
 

I would leave it as it is. Remember you don't want to be that "jerk" spoken about by the next owner who "did that".
I know there are current owners that have called me at least a jerk when they inherited some of my teenage electrical bird nests.
Let you without "ingenious short cuts" in your past cast the first stone, Chap.

Re: 6 volt positive ground
 

The only REAL difference between positive and negative ground is how the battery is connected.

If you're trying to think your way through imagined differences, your head is going to explode.

Re: 6 volt positive ground
 

Leave it positive ground. Remember, these vehicles were driven for many years and thousands of miles as Henry intended. Still works 4 me. m

Re: 6 volt positive ground
 

I think this is excellent advice. I’ve done a lot of wiring on on neg. ground equipment and I always “ over think” the pos. ground issues.... Mark

Re: 6 volt positive ground
 

Agree with Chap, keep it pos. ground as it was originally and it will be easier to remember down the line just what you did. I changed my '39 to negative ground when I replaced the generator with and alternator....the alternator was wired to be negative ground....and I always had to look at the battery to remember what I had done when I replaced things like the electric fuel pump, etc. It's easier for me to remember the "red" wire goes to ground!!!

Re: 6 volt positive ground
 

Just a side note. When people change to 12 volts the only reason they change to negative ground is to be compatible with newer electronics that are 12 volts negative ground. Other than the compatibility issue there is nothing better about negative ground. Leave your car positive ground, if it isn't broke, don't fix it until it is.

Charlie Stephens

Re: 6 volt positive ground
 

Lots of good advice but still can't figure out why there was a positive ground. My electrical background doesn't comprehend putting a cable from the positive terminal to the frame of a vehicle, am I missing something here?

Re: 6 volt positive ground
 

At one time it was considered an advantage to use positive as the groung. With the addition of more modern electronics the advantage switched to negative ground and the manufactures slowly switched over. Solid state devices, diodes, transistors, etc are concerned with polarity, but most of our flathead devices do not and the ones that do (coil, generator, ammeter) are easily adapted. Positive and negative are just names, very few devices care. If you want to add to the confussion, AC is changing + & - 60 times a second!

Re: 6 volt positive ground
 

Both Ford and Chrysler used positive ground for decades. Dont try to overthink what is proven to work, work well, and be reliable. Screw the red wire down and go have a drink.

Re: 6 volt positive ground
 

I have heard that positive ground is less susceptible to corrosion problems. With only 6 volts to "push" through the system, I suspect lessening corrosion was more important than it is with 12 volts.

Re: 6 volt positive ground
 

Doesn't direct current flow from negative to positive? So why not?

Re: 6 volt positive ground
 

All depends on how you look at it. Electrons have a negative charge, and move toward a positive charge. However you can also look at it as positive holes (missing electrons) moving from positive to negative. It is really not important unless you are into theoretical stuff. There is current moving through a wire and it produces an electric/magnetic field around it. For most applications in older cars it doesn't make any difference which direction the current is flowing as long as it is consistent to the application.

Re: 6 volt positive ground
 

That is true, well maybe. But I think it is so minuscule to other factors like moisture, normal wear, and road conditions.


6v I'd just stay pos ground. Keep it simple. 12v well... go neg ground.


But maybe these work? I don't know... https://www.youtube.com/watch?v=I2B7ozAEe2w

Re: 6 volt positive ground
 

Just to add to your confusion, you can buy a step-up transformer which converts to 12v neg ground to run modern devices. But you have to make sure they are isolated from the car.

Re: 6 volt positive ground
 

The question is can it be changed to neg ground? The short answer is yes. Others pointed out how to do it but the original post did not say why he wanted to change it around. If he had we might have been able to give him more pointers. I have 6v pos grnd in my 49 but float a power point to run my GPS. Works fine for me.

Re: 6 volt positive ground
 

6-volt systems always needed all the help they could get for reliable service. It was known after the Model T era that the flow of electrons worked better for positive ground. Once the 12-volt era change came in, it was determined that the higher voltage would be fine using negative ground. A lot of electronics were already based this way for non automotive use so it was natural to go this route. In the UK, they still used positive earth on 12-volt systems for a while since they went to 12-volt first but it was eventually changed over for essentially the same reasons.

Re: 6 volt positive ground
 

Not with this one. http://www.antiqueautomobileradio.com/


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