Butt coupler / joint vs continious run for resistance loss

1840 Views 29 Replies 6 Participants Last post by kennybobby, 4 mo ago

Jeep Man

Discussion Starter · 4 mo ago

So, any super nerds out there that can help - I'm using Amphenol's G2 series 300 connectors for my 2/0 cable.

All these high-end connectors require multiple tooling and time to assemble - man tear ($$$) are at the feet of stupid mistakes like forgetting to mount a ring before you did this-or-that and now it can't be undone or reversed or blah blah blah (<cursing and being forced to order a new $100++ connector).

So, the question I have is, would a pig-tail design reduce the resistant of the overall run - point A Connector to point B connector vs point A Connector to butt joint to point B connector.

I can build a G2 connector in a controlled environment (my dinning room) attached to say a 24" length of 2/0 cable then make my run in the vehicle, join the butt to butt end to the pig-tail and Bob's you Uncle.

The question is, how much do I loose in resistance with a butt joint?

Obviously, I would use an industrial, hex crimped, tinned, copper connector then a double wall, adhesive heat shrink over it for both strength and water proofing.

Thoughts?

- Patrick

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kennybobby

· #3 · 4 mo ago (Edited)

It looks like a good solution; probably couldn't measure any significant resistance increase unless the crimp wasn't done well.

What is the overall length of the 2/0 that would be used x (0.000080 Ohms per foot) --kinda hard to measure resistance that low.

In my book the Green One is the expert on crimping, Hammer Time ; couldn't find his dissection pictures but those are must see.

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kennybobby

· #6 · 4 mo ago

That is a link to one of his posts with a video, from there you can search all of his posts. run your mouse over it should be underlined, click it and go.

Orange is the standard color to identify HV cables on EVs.

The losses due to a good crimp will be very small and below your level to detect unless you have some expensive equipment.

What is the max or peak current that you expect or want to carry?

You may need some extra measures to increase the insulation of the crimped joint; tape and heat shrink wouldn't cut it. Look for the industrial solutions.

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kennybobby

· #10 · 4 mo ago

You didn't mention it was shielded cable initially; i don't know why you omitted that detail.

If these are for your motor wiring (3-phase) then just use a solid run without a crimp; the break in the shield will negate using a shield.

If these are for the + and - of the HV run from the pack then crimp might be okay, but i don't understand about using a shield on a single wire in a pair.

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kennybobby

· #30 · 4 mo ago

Get a drill bit that will fit into the connector and use it like a file by hand pushing and pulling while rotating to get an even "cut" off the ID. Or,
Use a rat-tail file.

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