DIY Electric Car Forums banner

Butt coupler / joint vs continious run for resistance loss

1835 Views 29 Replies 6 Participants Last post by  kennybobby
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.


- Patrick
1 - 1 of 30 Posts
Interesting discussion. Although is is intuitive to assume a lug connection you can swing across a pit of alligators on is better than one that is (just enough) electrical connection. My understanding is that stranded wire has higher ampacity than a solid copper crossection, which is what you are doing when you crimp the hell out of a stranded wire into a solid copper wad at both ends of a butted connection. So maybe the goal is to size your butt connector to allow for some interlacing of the strands inside the butt and then just crimp over the area of this interlacing. Also, to back up to ensure more "mental insurance" consider the need to be concerned at all about this issue and look up the time to heat up under actual intended load. Here is a website/calculator that will tell you how long it will take to max the insulation rating for your wire. If you are using 00 wire and it says 350A constant load capacity, then why does Tesla use this size wire and hook it up to a motor that can see 1300-1500A for short durations. Using the website below you can play with figures that you get from measuring the resistance of your butt connection vs a un-butted length of wire.

See less See more
1 - 1 of 30 Posts