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Choosing flexible busbars

brum

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I ordered two different types of flexible busbars in order to compare them. Flexibility comparison is done without measurements. Just by the feeling I got while flexing them. The two types of busbars that I've tested are on the image below. The first is the laminated one from Weber Power Tech. The second is the braided one from the Minerals Official Store.

And here are the results:
  1. Axial flexibility - the braided busbar is the winner. The laminated one requires a lot more force to change its length.
  2. Radial flexibility seems equal.
  3. Contact area - the braided one wins. The laminated one has an oval hole while the braided one has a round hole.
  4. Price - the braided one is cheaper.

The most important aspect is axial flexibility. This is what the busbar should mitigate while cells are expanding and contracting. For me the winner is clear.

Docan also offers braided busbars. The price is even lower, but the middle part is not tinned according to the pictures. I'll be using these for my build due to the price difference.
 

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Interesting topic.
Another important aspect is the hability to be able to drill and tap a hole to join BMS cables
 
I see different options for that. Soldier the wires directly or use the cell stud to connect them. I'm likely going for soldered balancing leads.

The laminated one is a kind of monolith at the ends. And it should be straightforward to drill and tap it. I'll probably try this on the braided sample I have, but my expectation is that it won't be reliable.
 
I see different options for that. Soldier the wires directly or use the cell stud to connect them. I'm likely going for soldered balancing leads.

The laminated one is a kind of monolith at the ends. And it should be straightforward to drill and tap it. I'll probably try this on the braided sample I have, but my expectation is that it won't be reliable.
Looking forward for your experiences in the braided busbars!
What is the max amperage they handle?
 
The braided one is advertised for 140A. The other one does not state max current.
 
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Some have reported the braided busbars will not hold torque as they tend to 'squish' after some time requiring constant retorqueing.
 
Braided cable was only used as grounding strap when I worked as a technician. I've always been reluctant to install a braided busbar. The flexibility is awesome, I just would not want to run it at near full power for any length of time, day after dya, month after month, year after year.
 
Some have reported the braided busbars will not hold torque as they tend to 'squish' after some time requiring constant retorqueing.
The one that was given as an example back then was just plain braided wire (no crimped copper tube at the end). I have serious doubts that the one that I've pictured will have that issue.

But I can test that with the sample I have. I'll torque it down to 8Nm. The same will be done with the laminated one. In a week I'll check to see if there is a difference.
 
The one that was given as an example back then was just plain braided wire (no crimped copper tube at the end). I have serious doubts that the one that I've pictured will have that issue.

But I can test that with the sample I have. I'll torque it down to 8Nm. The same will be done with the laminated one. In a week I'll check to see if there is a difference.

Mine are 1” four ply, they were soldered in fixture and squeezed while hot. Then embossed in the terminal/nut contact area to cold work and make parallel the metal with a force of 10,000 lbs. After all that I still had to re torque it ten times before it wouldn’t give anymore. Finally after six months they don’t move. Apparently the metal cold flowed. This would have been a disaster if it was in an enclosure where you wouldn’t check it. For all my work, I rate that as a fail.
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This is the "stock one".
 

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Mine are 1” four ply, they were soldered in fixture and squeezed while hot. Then embossed in the terminal/nut contact area to cold work and make parallel the metal with a force of 10,000 lbs. After all that I still had to re torque it ten times before it wouldn’t give anymore. Finally after six months they don’t move. Apparently the metal cold flowed. This would have been a disaster if it was in an enclosure where you wouldn’t check it. For all my work, I rate that as a fail.

Not to derail the thread, but how do you like the active balancer?
 
They worked fine, but they need a voltage switch to turn them on above 3.42 volts per cell and they need time above that voltage to do the job. That’s an old picture. I went to a Neey smart active balancer and that has many times the balancing power but then the Daly bms got weird. So the smart simple move is I got two 200amp JK bms’s and get new buss bars/jumpers. So the Heltec is retired and the Neey/Daly will be retiring. What I made is diagonal 2/0 cables jumpers because I didn’t like the 7mm wide slot in the laminated buss. I thought it would greatly reduce the contact area and current capacity versus 1/4” of a lug. Found out that the Ancor cable/Selterm lugs with a small bow in it for flexibility had .08/.07 M ohms versus the stock buss .06 which isn’t bad. Brum noted the laminated has .09 M ohms and that’s still excellent. The problem I just realized is with cable jumpers is when the ends are free, it’s quite flexible but once you lock down the lug angle (torque the terminals) it’s as stiff as a rod! So my thinking is despite the overly large slot and no reports of frequent re torquing, the laminated buss may be the way to go if they can handle the current with small terminals. My problem is I already made 31 jumpers so I’m going with them. They may be pivoting at the terminals because my antioxidant is “green grease” and they are torqued only to 4Nm with a Bellevue washer. I’ll checking torque. Hey, life is learning.
 
They worked fine, but they need a voltage switch to turn them on above 3.42 volts per cell and they need time above that voltage to do the job. That’s an old picture. I went to a Neey smart active balancer and that has many times the balancing power but then the Daly bms got weird. So the smart simple move is I got two 200amp JK bms’s and get new buss bars/jumpers. So the Heltec is retired and the Neey/Daly will be retiring. What I made is diagonal 2/0 cables jumpers because I didn’t like the 7mm wide slot in the laminated buss. I thought it would greatly reduce the contact area and current capacity versus 1/4” of a lug. Found out that the Ancor cable/Selterm lugs with a small bow in it for flexibility had .08/.07 M ohms versus the stock buss .06 which isn’t bad. Brum noted the laminated has .09 M ohms and that’s still excellent. The problem I just realized is with cable jumpers is when the ends are free, it’s quite flexible but once you lock down the lug angle (torque the terminals) it’s as stiff as a rod! So my thinking is despite the overly large slot and no reports of frequent re torquing, the laminated buss may be the way to go if they can handle the current with small terminals. My problem is I already made 31 jumpers so I’m going with them. They may be pivoting at the terminals because my antioxidant is “green grease” and they are torqued only to 4Nm with a Bellevue washer. I’ll checking torque. Hey, life is learning.
Let me know how it goes with the JK bms.

I'll probably be doing 2/0 jumpers diagonally and compression.
 
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