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source for braided interconnects?

6332 Views 28 Replies 11 Participants Last post by  mizlplix, 
dtbaker
I have been tossing drawings around to various places, but can't find a US source willing to go less than $7.95 each for braided interconnects.

I would LIKE to have braided to lower the 'jiggle strain' on terminals, and fit both orientations of cell stacking without modification...

Anyone have a less expensive source? The AU source EVworks.com has them listed, but out of stock...
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E
maybe these guys can make them custom- they have a good selection of all different types/sizes and also a custom order sheet. I have no idea of costs though....
http://www.ags.bz/

mike
www.EV-propulsion.com
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EVfun
You must be looking for the 80-8 size. You could shoot an e-mail off to them asking about a time frame to get them back in stock. They where pretty good about getting the parts I needed back in stock. Popping over to their site it looks like the price for 50, shipped to the USA would be about $271 US, less than $5.50 each.

Disclaimer :) I get nothing from EVworks for saying nice things about them. I am a regular customer who has been very satisfied doing business with them on several occasions. Plus, they have some cool things I don't see available from local suppliers.
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Jimdear2
You can buy the raw braided stock in lengths from wire supply houses.

For small low amprage jobs, de soldering braid works nicely

Cut to length.
Use a properly sizes tapered tool to force a hole in the braid.
Get good solder and paste flux
Clamp a heat sink (two big chunks of something like steel) to the braid where you want the soldered portion to stop.
Apply flux and heat end of braid with Big Iron or sutible Propane Torch.

Method One:
Apply solder to braid up to edge of heat sink, then let cool
Use taper tool and dead blow hammer to final form

Method Two
Place a suitable brass washer on end of braid
Solder washer to braid and then braid up to the heat sink
Use taper tool and dead blow hammer to final form

Method Three
Wrap suitable thin brass or copper sheet around end of braid
Solder sheet to braid and then braid up to the heat sink
Use taper tool and/or drilland dead blow hammer to final form

I've used these methods, with a little pratice and you can turn out professionl quality braided conductor strips.

Hope this helps,
Jim
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dtbaker
Jimdear2 said:
You can buy the raw braided stock in lengths from wire supply houses.
...
I've used these methods, with a little pratice and you can turn out professionl quality braided conductor strips.
Click to expand...
I hadn't thought of DYI braid connectors, but I guess it would be no more labor intensive than building our own welding cable connectors for floodies. If I can get manufactured ones for less than $5 ea though, it would be worth the time savings to buy them.... so far the low-bid US is $7.95. The AU evworks.com has them advertised for less, but shipping would bring it back up a bit....
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Jimdear2
dtbaker said:
I hadn't thought of DYI braid connectors, but I guess it would be no more labor intensive than building our own welding cable connectors for floodies. If I can get manufactured ones for less than $5 ea though, it would be worth the time savings to buy them.... so far the low-bid US is $7.95. The AU evworks.com has them advertised for less, but shipping would bring it back up a bit....
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Dan,

Is there anything on an EV that doesn't cost an arm and a leg.:eek:

Except of course, your own labor :D and the current to charge the batteries, but the cost of that power is going up fast :mad:).

Jim
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dtbaker
Jimdear2 said:
Dan,

Is there anything on an EV that doesn't cost an arm and a leg.:eek:

Except of course, your own labor :D and the current to charge the batteries, but the cost of that power is going up fast :mad:).

Jim
Click to expand...

The 'opportunity cost' of my time is high even though the cash value is not... at least my cost of electricity is fixed now that I am fully offset with a big PV on the house.
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B
dtbaker said:
Anyone have a less expensive source? The AU source EVworks.com has them listed, but out of stock...
Click to expand...
I just recieved an email from EVWorks.com.au. They're getting a shipment of something in about a week. Maybe they'll be on it. Can't hurt to ask (email turnaround time was under two days).
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dtbaker
ok folks, I am still pursuing a US source, just because....

I don't particularly see the reason the AU version has slotted their terminal tabs. I am assuming that the braid is flexible enough that we ought to design the connectors with the LONGEST length and 'flex' the braid to accomodate the shorter connections for smaller capacity batteries with the same terminal size. This would allow the tabs to have simple 9mm holes rather than slots, for better clamping force, more area in contact w/ terminal, and less expensive to make.

Is there a problem 'flexing' the braid? why not order the longer ones in all cases so they are all the same?

Seems like 8mm holes would be too small for the 8mm studs to fit thru, shouldn't the holes be 9mm?

Moving on to finalize the design I am requesting a quote for... with TS 100ah cells, the center-to-center distance between terminals is either
1-5/8, or 1-7/16... only 3/16 difference. SO the nominal distance I would ask for the TS 100ah is 1-3/4 to provide a little flex in the 'longest' case.

my question to the group is what is the LONGEST c-c nominal distance on cells having 8mm studs? The AU ones show a nominal pitch of 80mm, but I would like to verify with some of you who actually have TS and CALB cells to actually measure the distances between terminal centers stacking cells both ways.

By designing one size, the quantity goes up, price comes down... as long as we are sure we can 'flex' the braid easily enough to accommodate shorter c-c.
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EVfun
dtbaker said:
ok folks, I am still pursuing a US source, just because....

I don't particularly see the reason the AU version has slotted their terminal tabs. I am assuming that the braid is flexible enough that we ought to design the connectors with the LONGEST length and 'flex' the braid to accomodate the shorter connections for smaller capacity batteries with the same terminal size. This would allow the tabs to have simple 9mm holes rather than slots, for better clamping force, more area in contact w/ terminal, and less expensive to make.

Is there a problem 'flexing' the braid? why not order the longer ones in all cases so they are all the same?

Seems like 8mm holes would be too small for the 8mm studs to fit thru, shouldn't the holes be 9mm?
Click to expand...
The braided straps don't compress very well. That is not a hollow braid, it is pretty much all copper wires the whole thickness. It has the wire of a 1/0 cable in about 1/8 inch of thickness. I certainly appreciate the slots on my EVworks braided interconnects.

I have the short 60-6 interconnects. They flex fine up to perhaps 1/16 inch difference in height and perhaps 10 degrees. Small amounts of movement are easy but the copper starts fighting you if you want to make bigger movements. I'm sure the flex improves as they get longer.

I can't speak to the 8mm holes because I have the straps with the 6mm holes. I had no problems putting a 6mm bolt through the holes. They left a little breathing room on the size.
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dtbaker
EVfun said:
The braided straps don't compress very well.
Click to expand...
I wouldn't expect compression... but would hope that the braid is flexible enough to hand-form a 'hump' if needed to adjust the c-c distance. The vendor I am speaking to is telling me that they would need to use TWO braids to safely carry continuous 400amps.... and can't get the cost down below about $7 per piece with copper prices being what they are...

so, I guess the evworks.com is the best source for time being.

Did they include any info about continuous amp rating?
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DIYguy
Bump... Hey DT. Any luck with this pursuit?

Thx
Gary
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dtbaker
DIYguy said:
Bump... Hey DT. Any luck with this pursuit?

Thx
Gary
Click to expand...

I did order 4 for evaluation.... they are significantly more expensive at $7-ish compared to the $3.50-ish for bus bars. I did play around with them a little, and it IS possible to manually shorten by making the hump bigger. I'll take some pix sometime and post. The ones I got are 'double braid' and look like at least as much, or more copper than bus bars to carry amps.

My conclusion at this point is that it probably is not worth the extra cost over manually adjusting a regular bus bar... but is an option.
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DIYguy
yes, well... I was thinking more about the stress on the terminals. I bought the copper connectors with my batts for... I think it was $1.30 each.

I worked with a company that made all kinds of air cooled and water cooled, jumpers and shunts of all kinds for resistance welding. I did fwd them a few dwg's of what we would like to see. I know they are capable of making them as they do some similar straps now that are longer. They use to do some pretty custom stuff for me in industry. We'll see what comes back. If I don't hear back from them by tomorrow via email, I'll give em a call.
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DIYguy
Got a reply. No problem making them. They will prepare a quote. There may be a price break on quantities.. if anyone is interested.... not sure yet. Will advise.
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dtbaker
I am interested.... if the price can come down a little. I do think the braided connectors would be easier on the terminals. As an engineer, I am a believer in avoiding solid connectors across joints that are likely to vibrate, and may have significant thermal expansion/contraction if possible.

I hacked up a quick drawing.... and specced a 'double braid' to carry a continuous 500amps. The final price for 1-100 units was $6.17 ea, and dropped a little for higher quantities

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major
dtbaker said:
.....to carry a continuous 500amps.
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Don't you think that is overkill? Unless you're running dual 11 inch motors ;)
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dtbaker
maybe 'slight' overkill, but not much for systems running at lower voltages. I know that at 96v, my motor/controller was pulling a steady 250 amps at 50mph coming up just a slight grade, and even my wimpy curtis 1221 is rated to pull a constant 400 amps if need be for highway travel. This is in part why I went with 2/0 welding cable for the other HV connections in the traction pack.

In my particular case, with 100ah cells and upgrading to 120v, I hope to not have extended pulls over 300 amps. But, in a more general case where people are installing 200ah cells, and 1k Zillas, it would be silly to under-spec the bus bars.

I think it would be penny-wise, but dollar-foolish to spec the bus bars lower capacity than the controller.
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major
dtbaker said:
I think it would be penny-wise, but dollar-foolish to spec the bus bars lower capacity than the controller.
Click to expand...
Hi dt,

500A continuous is like twice the rating of 2/0. And that will make these braided connectors stiff, hard to handle and costly. For the rare installation which requires the extra capacity, just use 2 of them, where each is more suitably rated at 250A.

My opinion,

major
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DIYguy
DIYguy said:
yes, well... I was thinking more about the stress on the terminals. I bought the copper connectors with my batts for... I think it was $1.30 each.

I worked with a company that made all kinds of air cooled and water cooled, jumpers and shunts of all kinds for resistance welding. I did fwd them a few dwg's of what we would like to see. I know they are capable of making them as they do some similar straps now that are longer. They use to do some pretty custom stuff for me in industry. We'll see what comes back. If I don't hear back from them by tomorrow via email, I'll give em a call.
Click to expand...
I got this price last week. Not worth talking about. Way too high. They do have silver plating instead of tin...but still, they can't touch the lower pricing.
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