Batttery Cable Hookup

I"m sorry to waste your time with what I am sure is a simple question for you experts. My "52H is finally back together and the last thing I need to do is hook up the new battery. The system was converted to 12V some time ago and I have an alternator installed. Do I hook the ground strap to the negative or postive terminal on the battery? Thanks,

Josh

In fact smaller cables may actually help extend starter life by somewhat limiting starter "inrush" current. This in turn reduces shock on the starter and drive when you first hit the starter switch.

But even the smaller cables still let the starter spin the engine way faster than the stock 6 volt system ever could.

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Josh - Like Jim says: Unless you have a real oddball alternator arranged (and marked) for positive ground, the negative battery cable is the one that must be grounded.

John T

PS Looks like Im only doing the Wico Mag Workshop at New York Expo in July (Friday 10 AM I think) but we have several open round tables where anything may be asked, maybe you better be there if I get stuck??

After I first converted my Super M to 12 volts (and retained the original 1/0 cables) when the starter engaged the mechanical shock was so severe you could feel it even in the seat. After a couple seasons of getting slammed like that the bendix blew apart and had to be replaced.

On the advice of the guy at the starter shop I substituted a lighter #4 for the #1/0 hot cable when reinstalled the starter. Discovered this noticably softened the initial shock of starter engagement, yet still permitted the starter to crank the engine extremely fast.

My theory: The slight added resistance of the smaller cable reduces the initial starter inrush (locked rotor) current and initial armature acceleration. This then reduces the mechanical shock of bendix engagement. However once the starter gets spun up, the faster armature RPM results in higher back EMF which causes the starter to draw LESS current than it does on 6 volts. (Higher armature RPM = greater back EMF = less running current). At this point the higher resistance of the #4 cable becomes essentially inconsequential.

(Disclaimer: I could be all wrong. This is simply how I rationalized what I've observed and stuff I remember from EE courses taken 35+ years ago...)

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"maybe you better be there if I get stuck??"

Come on John T!!! Unless you "get stuck" in a muddy parking lot at the Expo and need a tow, I doubt there's much I'll be able to help YOU out with...

Heck - I can barely SPELL "Wico", let alone answer questions about 'em!

John T (old n rusty but still wanna learn)

Ie. a #1/0 1045 strand copper welding cable, #1/0 273 strand locomotive cable, #1/0, 133 strand automotive battery cable, #1/0 19 strand aerial cable and a 0.083" square inch solid copper bus bar all exhibit exactly the same DC resistance per unit length. The only reason for different strand diameters/numbers of strands is to provide the degree of mechanical flexibility required for a particular application.

However for AC currents at RF frequencies all I know is skin effect and conductor surface area become VERY critical. (Beyond that RF is a field which I don't begin to comprehend!)