Cell Terminal Strain Relief, bus bars, and compression

HRTKD

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Somewhere South of Denver
The initial question I was responding to was something to place the batteries on to isolate some of the vibration from travel so it doesn't reach the batteries as much. I wasn't thinking about space the individual cells with the mat material. I haven't decided yet if I'll find something thin to put between the batteries that still permits the use of the supplied bus bars for interconnect or whether I'll use built cables for that purpose.

I don't know how much you can isolate the batteries from the vibration that the rest of the vehicle gets. The batteries need to be securely fastened down to ensure they don't move should there be abrupt changes in motion (emergency braking, big potholes, etc.). That connection to the vehicle is going to transfer vibration.
 

Gazoo

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It's my understanding the CALB style busbars have thin busbars stacked on top of each other. The Aliexpress busbar appears to be one piece.
 

jwelter99

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Dec 6, 2020
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These look nice, but how flexible can they really be?

They are a bunch of 0.1mm thick thin sheets stacked and somehow fused at the bolt ends. 30 layers to get 3mm. I have tried these and they work but my fear would be corrosion between the 28 layers of raw copper as only the top and bottom are tin plated.

They do flex a bit -- more that enough to absorb the max of 1mm of cell swell/shrink over the entire SOC (0.5mm per cell)

Think 30 layers of copper like foil layered.
 

Marinepower

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These are the bussbars Calb sells to use with their cells.
These are my EVE 280 cells with the CALB bus bars. These CALB bus bars were used to replace the solid buss bars that came with the EVE cells to hopefully allow for some movement btw cells. This is in a mobil application.

Too bad they are not zinc plated. I use some dialectic grease on the cell contact to try to protect from oxidization.

This set up is still a work-in-progress. I still need to add some insulation btw each cell and do a bunch of cable management.
 

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jwelter99

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These are my EVE 280 cells with the CALB bus bars. These CALB bus bars were used to replace the solid buss bars that came with the EVE cells to hopefully allow for some movement btw cells. This is in a mobil application.

Too bad they are not zinc plated. I use some dialectic grease on the cell contact to try to protect from oxidization.

This set up is still a work-in-progress. I still need to add some insulation btw each cell and do a bunch of cable management.

Like the BlueSea contactor - using a 7713 myself. How/where did you get those bus bars from the contactor to the class-t?
 

Marinepower

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Like the BlueSea contactor - using a 7713 myself. How/where did you get those bus bars from the contactor to the class-t?
The ML 7713 works great in this application. On the charge side, I am also using a 220amp Victron BatteryProtect as a relay for a high-voltage lockout ( as a second 7713s was a bit pricey).

If i understand your question correctly, the bus bar from the class-t fuse the ML 7713 relay is just one of the busbars that came with my cells, bent into a 'L' shape. Not ideal and I should consider doubling it up or finding thinker bar stock. However my sustained loads are less than 75amps typically and it seems to stay cool, even under larger loads.
 

self_sufficient_25

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I would like to share my findings.
I build my packs with 1/4 aluminum plates held by C channel with spacers in the center.
Which serves two purposes one to apply pressure to the center and to give it a little spring.

Also I have a solid layer of anti slip drawer mat, in between the cells.

What I found is from a low charge to full, there is no overall expansion of the pack. I believe the anti slip is taking up the swelling.

So I believe that would address the concerns on buss bar stress.

Also the fact that it is anti slip, makes the cess stick together to form a solid bank. So very little to no movement between the cells.
 

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chrisski

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Is that aluminum plates for mobile like an RV or fixed like a house?
 

self_sufficient_25

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These are my EVE 280 cells with the CALB bus bars. These CALB bus bars were used to replace the solid buss bars that came with the EVE cells to hopefully allow for some movement btw cells. This is in a mobil application.

Too bad they are not zinc plated. I use some dialectic grease on the cell contact to try to protect from oxidization.

This set up is still a work-in-progress. I still need to add some insulation btw each cell and do a bunch of cable management.
Dialectric means not conductive.
What I use and recommend is a antioxidant like Ox-Gaurd.
 

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Marinepower

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Dialectric means not conductive.
What I use and recommend is a antioxidant like Ox-Gaurd.
Thxs SS-25 for the tip on the contact grease.

All the marine guys seem to be irrationally keen on this product. "NO-OX-ID"

See: https://www.sanchem.com/electrical-contact-lubricant.html

I have never been able to find NO-OX-ID in Canada and have been using the Permatex dielectric as an alternative. https://www.permatex.com/products/s...tenance/permatex-dielectric-tune-up-grease-2/

No OX ID Seems similar to what you are recommending.

MP
 

BobR

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Thxs SS-25 for the tip on the contact grease.

All the marine guys seem to be irrationally keen on this product. "NO-OX-ID"

See: https://www.sanchem.com/electrical-contact-lubricant.html

I have never been able to find NO-OX-ID in Canada and have been using the Permatex dielectric as an alternative. https://www.permatex.com/products/s...tenance/permatex-dielectric-tune-up-grease-2/

No OX ID Seems similar to what you are recommending.

MP
Ox Gard is what I use.
 

self_sufficient_25

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Thxs SS-25 for the tip on the contact grease.

All the marine guys seem to be irrationally keen on this product. "NO-OX-ID"

See: https://www.sanchem.com/electrical-contact-lubricant.html

I have never been able to find NO-OX-ID in Canada and have been using the Permatex dielectric as an alternative. https://www.permatex.com/products/s...tenance/permatex-dielectric-tune-up-grease-2/

No OX ID Seems similar to what you are recommending.

MP
Yes I also live in Canada. And also couldn't locate, No Ox.

You should be able to find Ox-Gaurd
At Home depot and Home Hardware.
 

APhoton

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I'm sure everyone is tired of talking about cell compression. I know I'm tired of reading about it (I've read many posts on many threads about it).

What I'm hoping to discuss in this thread is compression and bus bars, but only as it relates to the integrity of the terminals. I have 16 EVE 280ah from Amy on the way, and I'm coming up with my pack design, which will be a 4P4S design. My original plan was to build a threaded rod box with aluminum end plates, snug them lightly at 50% SOC, and use the bus-bars supplied by Amy (2mm x 20mm). However, all this reading about compression has got me worried about the strain on the terminals when the cells expand and contract.

What I'm asking for is 1st hand experience or informed opinions on whether the fixturing discussed above would mitigate strain on terminals with solid bus bars. Since I'm building the pack for a boat, and I'm already slightly nervous about the physical durability of these big 280ah cells, my first priority is reducing any physical strain on the cells. Improved cycle life is far down the list.

I just don't have a sense of how much force the terminals would experience (Usually charging less than 0.2C and discharging less than 0.3C) with such a setup.

At this point, I'm getting so concerned about terminal strain that I'm leaning toward interconnecting with curved pieces of wire and lugs, maybe 1/0 or 2/0. Alternatively, I'm also thinking of putting spacers between each cell (corners and edges) and letting the middles of the cells "breath" even though I'd give up cycle life, maybe this would reduce strain and I could keep the rigid bus bars.
Thanks for starting this thread. I'm thinking about same issue and considering connected cells with wire and lugs. Now, I too have 2mm x 20mm busbars. 2mm x 20mm = 40mm, so 1 AWG having a diameter of 7.35mm would have an area of 42.43mm. Would not 1 AWG wire replace a 2mm x 20mm busbar???
 

Marinepower

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I bought Ox-Guard at RONA and HomeDepot in Canada, as well as BMR carry it.
On SS-25s reco, I bought some Ox-Guard. Amazon.ca. also seems to cary it. It was about $5 for a small tube - free Prime delivery within 24hs.
 
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