Current flow

[Marc]

"Conventional" current flow discussions presume positive-to-negative flow. In truth, electrons flow from negative to positive - but for our purposes no harm is done by thinking in terms of conventional current with one notable exception: sparkplugs fire better when the electrons leave the hot electrode and jump to the cooler one. Although inverted on most oscilloscope displays, the actual voltage leaving the ignition coil is negative with respect to ground.
http://www.allaboutcircuits.com/vol_1/chpt_1/7.html

[500LbGorilla]

Yeah, I was going to talk about this, but it seemed like a lot of the posts here are not about VWs.. they seem to be about theory, and too much so.. much information here is not really used to deal with our cars. But yeah, conventional thinking is to refer to the displacement in terms of "holes". That is, as electrons move from anodic to cathodic relative charge, the displacement is thought of as holes between electrons being moved in the direction of current flow.

I *knew* I would use that EE degree before it was all over for me. There you are.

Thanks for bringing it up Marc.

[Marc]

a lot of the posts here are not about VWs.. they seem to be about theory, and too much so...

If it were left to me there would be no electrical forum, since I foresee it creating as much confusion as it resolves since so many of the problems/solutions are model-specific and best covered in the appropriate existing forum...unless they have a solid background in theory and possess basic troubleshooting skills, people trying to troubleshoot their own electrical problems will always need "cookbook" answers (i.e., "turn on the key and see if there's power where the black wire with the yellow stripe connects to the headlight switch") which often only apply to certain models/years.

But since the Electrical Forum is now here, what better place to cover the basic theory that applies to ALL electrical matters?

http://www.sengpielaudio.com/calculator-ohm.htm
www.autoshop101.com/forms/toyOH_2.pdf

http://www.shoptalkforums.com/viewtopic.php?p=756393

[sagaboy]

Why is it that my 1963 bug original battery positive terminal red wire is 3 times thicker (5/8 inch) than the earth wire (1/4 inch) connecting from battery negative to car chassis.

Wouldn’t it be obvious to VW German electrical engineers in the 1960s that electrons flow from negative to positive therefore, the earth wire should be equally as thick as or thicker than the positive wire?

In fact I have see many modern cars having the red battery wires double the thickness compared to the earth wire.

[Marc]

The direction of electron flow has absolutely no bearing on the size requirement of the cables.
It's not surprising that the insulation might be thicker on the positive cable in a negative-ground system, considering how much more dramatic its failure would be compared to the negative cables's. Some cars (including VWs) don't even use any insulation at all on the negative cable, so it appears far smaller than the positive cable.
Does your `63 still have its original flat-woven ground cable? It can handle just as much current as the 25mm² positive cable. If it has instead a round black-covered cable, someone has replaced it, possibly with one which isn't really big enough for a 6V system).

[All_talk]

Also, the length of the cable is one of two key factor in in its sizing, current flow being the other. Positive cables tend to be much longer than grounds.

Gary

[sagaboy]

Yes, it is flat woven copper from battery negative to chassic same size as the woven copper earth connecting between the tranny and body