Question about positive vs negative ground

[Member 10617]

Since I am new to positive ground cars, I need to make sure I understand:

I know that to remove a battery on on a negative ground car, detach and remove the negative cable first and then detach and remove the positive cable. To replace the battery, attach and tighten the positive cable first, and then attach and tighten the negative cable.

On a positive ground car, I assume that the procedure is reversed. Am I right?

 

[dklawson]

That is correct.

It's easy to remember if you focus only on removing and re-attaching the cable connected to the car body first.

 

[SaxMan]

What was the thought process in having a positive-ground system? It seems counter-intuitive.

 

[Pythias]

What was the thought process in having a positive-ground system? It seems counter-intuitive.

In the beginning.... . they (automobiles) were all positive ground. I believe it had to do with the direction of the flow of electrons, which actually move from the negative (more free electrons) to the positive.. It's been said (anecdotal evidence) that the batteries are less likely to lose their charge in a positively grounded car when its just sitting... I haven't converted mine to neg ground and I haven't needed a battery for ... WOW, not that I think about it.. I bought this battery before I move into this house, over 16 years ago. During the winter months (the rainy season in Washington state runs from late October till March) I try to drive it once a month and it's always held it's charge.

 

[Roger]

In the very beginning they were negative ground. Positive ground appeared in the thirties to preserve batteries.

 

[JPSmit]

Interesting responses - I just naturally assumed that because they were British - of course they would be counter intuitive!

 

[Member 10617]

Many thanks. There are some very interesting articles on the Internet about the pros and cons of positive grounding. Seems that not only do batteries last longer, but positive grounding apparently is less destructive of the old plastic coating on wires (?) and other benefits.

My car came with positive ground, and I will keep it. But with positive ground, I cannot install or plug in any modern devices or they will be destroyed.

 

[nomad]

Wow, I was aware of the battery issue but didn't realize it was that dramatic! Bill L are you sure you didn't forget at least one!

LexTR3, just a matter of wiring up a separate outlet or isolating metal bits. I'm going to put a GPS charger in my 65 that is still +.

Kurt.

 

[Pythias]

My car came with positive ground, and I will keep it. But with positive ground, I cannot install or plug in any modern devices or they will be destroyed.

Go to Radio Shack and get a fully insulated one. Tuck it up under the dash when not in use and pull it out to plug stuff (like a Garmin or a cell phone charger) in.

 

[histerical]

In the very beginning they were negative ground. Positive ground appeared in the thirties to preserve batteries.

So, why did they change it ?

 

[Pythias]

So far as I can tell, they changed it because everyone THINKS electricity flows from Positive TO Negative.

 

[dklawson]

I don't know how much research went into the article linked below but you may find at least one explanation for positive ground and the change to negative ground in the article linked below.

https://lajagclub.com/the-argument-for-positive-ground/

For additional thought, it was not just British cars that were positive ground. During the days of 6V electrical systems many American cars were also positive ground (but generally not GM) .

 

[Bayless]

Doug that article jogged some old memories. That is exactly how it was explained to me many years ago when I first got interested in LBCs and wondered why their electrics were "backwards."

 

[Member 10617]

Yep.... That is the interesting article I was referring to. Some friends have recommended that I swtch my car to negative ground, but I think I'll leave well enough alone.