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Battery wire gauge

Started by Katfish, November 09, 2022, 12:08:13 PM

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anlauto

I'm leaning towards the starter too  :dunno:
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration

Katfish

More info, went back and looked at the cable I bought and learned they are CCA.
Apparently that is copper clad aluminum, and not very good.
I did a cold start, will try to load the video, it did start immediately, but voltage dipped all the way down to 8V and 7V after hot.
So either the starter is drawing excessive current, or there is a big drop on cable.
Best I can do is pic, 1st is cold, 2nd is after car idled for 10min and then started after sitting for 10min.

Dmod1974

An amp clamp will tell you the other missing piece of the puzzle and whether the starter is drawing too much, or you somehow have a connection issue only when hot. Still leaning toward a starter issue....


anlauto

When the car is hot and not starting, is any part of the cable or battery connection too hot to touch ?
I've taught you everything you know....but I haven't taught you everything I know....
Check out my web site ....  Alan Gallant Automotive Restoration

Katfish

I'm definitely getting new copper cable to remove that variable, this CCA stuff isn't right for high current.
I agree, the hot part of the equation  doesn't make sense.
I'll take some measurements, and test drive it,  when the new cable.arrives and then go from there.

Katfish

Updating this to maybe help someone else.
My trans took a crap, so I was dealing with that.
Now that the trans issue appears fixed, I was able to verify the hot start issue is fixed.

I replaced the CCA (copper clad aluminium) wires with 00awg copper and that fixed the issue.
I now measure a 2V improvement in voltage drop when cranking the motor (9.5V vs 7.5V).

Not sure why it was only an issue when hot, but the pure copper wire works.
I guess there's a reason the CCA wire is 1/2 the price........

dodj

Quote from: Katfish on February 11, 2023, 06:53:25 PM


Not sure why it was only an issue when hot, but the pure copper wire works.
I guess there's a reason the CCA wire is 1/2 the price........
Electrical resistance in wires increases with heat.
"There is nothing your government can give you that it hasn't already taken from you in the first place" -Winston Churchill