Flexible Buss Bars

upnorthandpersonal

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He got back to me. The issue I see is he said they are rated at 70 amps . Even at the 2mm thickness. Up north said his were fine at 150. So I'm leery of bringing them in for others. My system devidesb250 amps between 6 battery sets so I'm not worried.

Thoughts?

Do you have the specifications of the braid itself? From the picture it looks similar, but this can be deceiving.

For everyone else, as a reference, these are mine. Width of the copper braid is 25mm (1 inch basically).

nickel_pated-jpg.39049
 

jamiegreen

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weldibg cable will add double the resistance per connection to a busbar
I'm not sure about doubling it? A good hydraulically crimped lug should offer very little resistance, although not as good as a straight busbar I agree.

My main concern is, I've gone through the effort of using springs to allow my batteries to expand and contract, I'm not going to stress the terminals with solid bars even if that takes several years to show it's effects
 

jamiegreen

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houseofancients

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I'm not sure about doubling it? A good hydraulically crimped lug should offer very little resistance, although not as good as a straight busbar I agree.

My main concern is, I've gone through the effort of using springs to allow my batteries to expand and contract, I'm not going to stress the terminals with solid bars even if that takes several years to show it's effects
ray made a cool little movie about it:

 

Marinepower

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These above linked busbars arrived. Long wait.

The quality and fit appears to be quite good and they are very flexible, able to easily expand and contract 2 - 3mm. Have not load tested them, but they are beefier than the solid busbars that come with the cells - which were fine for my maximum power draws / charging rate.

MP
Here is a video i discovered today showing the same busbars I purchased from Aliexpress (see above). Much better depiction than my snap shot and shows various options. Also demonstrates how flexible they are. Skip to minute 2;50.

For the price, they seem to be a winner.

 
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erarnund

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Now if only their holes were smaller to make better use of the terminal surface area... any thoughts on that?
 

upnorthandpersonal

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You can't spot weld copper to aluminium easily. Friction welding would be possible, but again, not something you quickly do without special equipment. Laser welding would be the best solution, but again, not something you quickly do in a garage.

Having all that said, I don't think it matters. We're talking solar applications, so we're usually not drawing 1C. Everything we do is a bit of a trade-off, but in my opinion your system will be more reliable with flexibility in the bus bar compared to finding the ideal connection between terminal and bus bar. Perfect is the enemy of good.
 

cmburns

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Has anyone tested any of these braided, or sandwiched layers of busbars, not just for actual current capacity, but movement failure? It's one thing to flex and unflex a handful of times, but I want this to last for thousands of cycles. I worry that at some point you get cracking and then some bad stuff starts happening.
 

upnorthandpersonal

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Has anyone tested any of these braided, or sandwiched layers of busbars, not just for actual current capacity, but movement failure? It's one thing to flex and unflex a handful of times, but I want this to last for thousands of cycles. I worry that at some point you get cracking and then some bad stuff starts happening.

Considering that we're talking only small amounts of movement from slight expansion and contraction I doubt this will be a problem.
This paper has some details and test results:

 
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