Plymouth Owners Club

General Category => Technical Discussion => Topic started by: mekanic on January 30, 2006, 11:51:14 PM

Title: Pos. or Neg. ground
Post by: mekanic on January 30, 2006, 11:51:14 PM
Howdy fellows, I have  another question for you about my 50 Plymouth clubcoupe. When I got the car it was being started with a 12 volt neg. ground battery. I was told the regulator was unhooked to keep from frying it. I went back to 6 volt battery, I have heard so much about positive as ground on this car, how can you tell whether it was a pos. ground or neg. ground system? Thanks Terry ???
Title: Re: Pos. or Neg. ground
Post by: Jim Benjaminson on January 31, 2006, 12:42:32 AM
All 6 volt Plymouth cars used positive ground, 1928 thru 1955.
Title: Re: Pos. or Neg. ground
Post by: mekanic on January 31, 2006, 08:02:49 AM
Thanks Jim.   Terry :)
Title: Re: Pos. or Neg. ground
Post by: John Hendricks on January 31, 2006, 11:39:38 AM
And make sure u use battery cables that are a big around as your thumb -- u won't have any starting problems.  I had my starter in and out several times and a couple of trips to the starter shop because it had 12 volt cables which simply do not carry enuff amps if there is a little corrosion.  With pos ground, the main corrosion occurs on the ground terminal.
Title: Re: Pos. or Neg. ground
Post by: OldCarNut on January 31, 2006, 02:41:50 PM
I went to a welding supply store and purchased #2 welding cable, then over to my helpful hardware man to buy the end connectors.  Works great.
Title: Re: Pos. or Neg. ground
Post by: Fr Mike on January 31, 2006, 09:06:03 PM
Did the welding cable thing with crimp-on terminals on my '36, too. Works great!

Fr Mike
Title: Re: Pos. or Neg. ground
Post by: mrodady on February 02, 2006, 12:11:21 PM
what was the reason for positive ground? It seams kinda strange.
Title: Re: Pos. or Neg. ground
Post by: POC-Admin on February 02, 2006, 01:29:25 PM
The reason to make the ground negative is that there is a lot of electronics in modern cars. 99.9% of modern electronic devices have negative ground. In principle they can be designed with positive ground, but technologically negative is preferred.  This was not true 20 years ago, when electronics was based on germanium.  When silicon become prevalent, npn and n-channel devices appeared to be more efficient and negative ground became more than common.  Remember the transistor was just starting to show up in 1955 when it had been invented in 1948.

The real reason they made negative ground in the first place is that current flows from Negative to Positive not the other way as one would think.  Why?  Because the basic unit of electricity, the electron, has a negative charge, and it seeks, and will flow to, a positive charge.  Lightning bolts go from ground to sky not the other way.