View Full Version : Just 1 stupid question--12 volt vs. 6 volt positive ground

01-17-2013, 07:13 AM
I'm to the point of rewiring my 50 stude champion . The interior is 90% done, the painting is near done, motors half way back together blah, blah, blah...... I need to re wire before I put the rear bumper back on. And I think I will go o the 12 volt negative ground. My question is---On a 6 volt positive ground my entire car is energized right? So how come when the jack goes under the car-that is not a direct short?
Just curious----and no, I am not an electrician. I'm an HVAC guy.:confused::cool:

01-17-2013, 07:40 AM
Rick, on a motor vehicle, ground only refers to which battery terminal goes to the vehicle's frame and, thus "common" side of the vehicle's electrics. It has nothing to do with Mother Earth.

Really, unless you want to use a late-model engine with a sound system and other contemporary electrics, I personally consider it inadvisable to change a 6-volt Studebaker vehicle to a 12-volt system. Those systems worked well when those vehicles were new and will continue to do so if properly restored and maintained. Changing to a 12-volt system introduces even more variables to the vehicle's electrics....and if you're shaky on electrics to begin with, why complicate matters?

Nothing like an unsolicited opinion, I realize, but fielding Turning Wheels Co-Operator questions for some 30-odd years has given our Advisors the thickest possible folder of problems arising when people loused up 6-volt vehicles trying to make them 12-volts "just because" it seems like everyone else is doing so. :ohmy: BP

01-17-2013, 07:42 AM
The positive or negative ground on a car is in reference to the cars battery not the Earth under the car. the Earth has no electric reference to the Battery as there is no connection between them. Electricity can not flow from the cars battery to the Earth unless there is metal contact between the Car battery and the Earth and a way for the electricity to return to the battery's other post.
To further confuse the subject; electricity flows from negative to positive. A car will function just fine with either the positive or negative connected to the cars frame. That is as long as every other component is connected correctly. The any electronic devices, alternator, regulator and the radio are the most critical.


01-17-2013, 08:04 AM
Thank you,,,the car ran when I pulled it into the garage...I think I will stick with the 6 volt. I like the AM push button radio. Can I get a 6 volt AM-FM somewhere for the glovebox?

01-17-2013, 08:09 AM
Thank you,,,the car ran when I pulled it into the garage...I think I will stick with the 6 volt. I like the AM push button radio. Can I get a 6 volt AM-FM somewhere for the glovebox? Rick

Sure, Rick; check some of our Turning Wheels advertisers, or vendors under Services Offered in Hemmings Motor News and such. It shouldn't be a problem getting your existing radio discretely fitted for FM. And congrats on leaving the car 6-volt, positive ground. You will not regret it. :!: BP

01-17-2013, 08:57 AM
Whether you intended to or not, I think you asked two questions:
1. Should I convert from 6 volt Pos. ground to 12 volt Negative ground?

2. Should I re-wire my 1950 Champion?

Bob has ably answered the first question. The answer to the second question depends on the condition of your current wiring loom. Is it the original wiring? If so, I would recommend that you re-wire the car to avoid a lot of electrical headaches and the potential for short circuits, even fire, after you get everything else back together. Furthermore, if you have the engine out of the car now, this is a great time to rewire. And don't just fix what you have or cobble together some homemade wire loom. Studebakers West makes picture-perfect, color-matched OEM replacement wiring harnesses at reasonable prices. Using their harness and the manufacturer's wiring diagram, you could completely rewire this car in a weekend or two. Finally, even if you do decide at a later date to convert to 12 volt, the replacement 6 volt harness will be more than adequate for 12 volt.

01-17-2013, 10:08 AM
Hey folks...this thread got me to thinking:ohmy: (very dangerous exercise for me). Seems like years ago... but somewhere in the dark recesses of my memory lurks a faint recall that there was an article in Turning Wheels about the six volt positive ground to 12 volt negative conversions. I believe the article discussed that the conversion is not so simple as adding voltage reducers to the gauges and changing polarity. Something about how the gauges are wired that will not allow them to read accurately when used in this manner.

Anyway...I decided to attempt some internet research before jumping in on this discussion. In doing so, I stumbled across this link...


Check it out...lots of good information for folks interested in learning about how circuits work.:)

When I did my first hot rod (Good grief!...nearly 50 years ago)...I bought a 12 volt to 6 volt converter. It was a simple ceramic device with two terminals and a wire coil. I think that what the device did was simply burn off 6 of the volts by heat and only allowed 6 volts to pass through. Crude little device but, it worked. In retrospect, I think it could also be dangerous, because it got so hot, it would burn you if you touched it. Wouldn't want it to be exposed to raw gas fumes.

Currently, I have three Studebakers that came with 6 volt systems and have kept them in their original configuration without any problems.

55 56 PREZ 4D
01-17-2013, 01:06 PM
Rewiring your car with a new, high quality loom will take care of 90% of potential problems that happen with old cars/old wiring.
It eliminates corroded wire and corroded/loose terminals.
To have a truly trouble free system requires attention to detail.
----Bare, clean, tight connections.
Especially all ground connections, throughout the body and frame.
NO rust, corrosion, paint, primer, dirt, grease, oil, undercoat.
Most components are grounded by connections thru the body or frame. Paint, undercoat, rust, corrosion must be removed where they connect.
[taillights, instruments, turn signals] If a turn signal is mounted on the grill the ground travels thru the grill THEN to the body to the battery.
Three connections, bulb socket to housing, housing to grill, grill to body. ALL connections must be clean and tight.
----Battery cables
#1/0 battery cables are good, #2/0 is better.
[NOT #1 gauge--#1/0 is much bigger]
Copper battery terminals are available, use them.
DO NOT use the cheap bolt on battery terminals found at the parts counter. Soldered or machine crimped, with shrink tube over the terminal/cable.
----The largest Cold Cranking Amp battery you can find.
Commercial 6 volt batteries are readily available.
You have to ask.
[Napa Commercial CCA 650 @ 0 degrees F]
----Generator, generating as it should.
----Regulator, regulating as it should.
----Starter, starting as it should.
Find a GOOD, QUALITY rebuilder to go through your starter, generator.
Turn the commutator, replace brushs AND brush springs, new bushings or bearings at armature.
6 volt positive ground [or negative ground if you decide to change] alternators are readily available.
----The starter is the biggest current draw.
Make the battery ground connection AT ONE OF THE STARTER MOUNT BOLTS instead of at the motor.
This and good cables will usually eliminate the dreaded "hot start, slow starter" problem so many people have.
----Above all - Bare, clean, tight connections.
Whether you go with 6 volt or change to 12 volt you will have to have go through the car and make good connections.

This really should be over in Tech shouldn't it ?

01-17-2013, 03:29 PM
Somehow when everyone started talking about this post, by the end, it probably should have been put in tech....But, the original question (in my opionion) did not warrant that.
My car came with a wiring loom in the trunk that the guy never installed (I got lucky). I have the wiring schematic/ color code and all...and yes it has the original wiring..and yes the motor is out......one more question if you please........I unplugged the old harnesses from the tail lights. From the male/female harness up to the rear lights, I have no colour code, the wires are faded. Can I hook up a 6 volt +battery cable to the car frame and touch the wires with the - to determine brake/running and turn? Or do I just look at the bulb....I assume double element is brake/turn....

01-17-2013, 04:49 PM
Yes you certainly can test your Tail lights with a Batt. in the trunk as you mention.
On the Dual Filament Bulbs, the small narrower filament inside the glass is the Tail Light, the wider, brighter one is for BOTH Turn and Stop on most Cars.

However, I do recall that some '47-'51's had TWO Bulbs because they were equipped with Turn Signals, so in that case the single filament Bulb would be Turn only.
Then the Bright Filament in the Dual Filament Bulb would be Stop only, leaving the dimmer one to be Tail Light.

01-18-2013, 12:48 PM
I purchased a new wiring harness for our '47 Champion from Studebakers West many years ago. When a couple of friends installed it, they found every wire was perfect in gauge, colour, terminals, and position relative to the others. We were shocked (almost literally) by how bad the condition of the original wiring was in the car, and it's probably only luck that the car had never burned. The engine was out of the car when the new harness was installed, which made the job much easier. Be sure to tag every old wire with its location when it is unhooked, then match the new harness to the old and tag each of its wires.