EVE-280 cells should these be clamped tight or spaced for expansion?

HRTKD

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The threaded rod can stretch. The longer the rod, the more stretching. How much stretch when only 10 inch pounds is being applied? I wouldn't think it would be much, but maybe enough to require retorquing. The weight bearing specs for the 10' threaded rod (1/4" diameter) I bought was surprisingly high. Much higher than I would ever put on it.

ArthurEld, that's quite the pack! Cell 9 (from the left) has some gap on both sides). Better get on that.
FIREdevil.gif
 

ArthurEld

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The threaded rod can stretch. The longer the rod, the more stretching. How much stretch when only 10 inch pounds is being applied? I wouldn't think it would be much, but maybe enough to require retorquing. The weight bearing specs for the 10' threaded rod (1/4" diameter) I bought was surprisingly high. Much higher than I would ever put on it.

ArthurEld, that's quite the pack! Cell 9 (from the left) has some gap on both sides). Better get on that.
FIREdevil.gif
Yea, I noticed you could see some gaps in that pic. I don't think that is any danger.
I might sort my cells but swelling hasn't been considered in the sorting process.
So far the only difference I have found is small capacity differences. I'll sort by that if I can't find anything else.
I'm using 3/8" threaded rod. 10 inch pounds barely pulls out the sag.
 

HRTKD

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Yea, I noticed you could see some gaps in that pic. I don't think that is any danger.
I might sort my cells but swelling hasn't been considered in the sorting process.
So far the only difference I have found is small capacity differences. I'll sort by that if I can't find anything else.
I'm using 3/8" threaded rod. 10 inch pounds barely pulls out the sag.

I just yankin' yer chain, having a little fun. :) It looks great!

I do wonder if the torque needs to change as the number of cells increases. Somewhere there's some math involved, but I can't imagine that 10 inch pounds for a 4s is enough for 32s.
 

Greybeard

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Mine may not be as pretty as the aluminum ones but I'm a wood guy. I built boxes just wide enough for 2 cells snuggly. Then an extra 2 inches beyond 4 cells deep. I cut a spacer plate and 2 wedges just tight enough to tap on with my palm when the cells were new and not charged up.
Bms is mounted to the spacer between the wedges. It works, they're heavier then I expected at 8 cellsPXL_20201102_000629034.jpg
 

ArthurEld

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I just yankin' yer chain, having a little fun. :) It looks great!

I do wonder if the torque needs to change as the number of cells increases. Somewhere there's some math involved, but I can't imagine that 10 inch pounds for a 4s is enough for 32s.
I haven't even charged those yet. It's going to get worse. Temporarily.
They might settle back into shape a little but people say they don't.
I suspect the cells scoot around from expanding and contracting.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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Well done, I see you thought ahead and put handles into the sides. Wee detail hat many leave as an after thought after some Blue Air is generated.

I'm also a Wood Guy, similar to your idea but I have hinged Clear Polycarbonate tops and heavy handles on the sides.
Sure makes things easier trying to heave about 40-44kg / 88-97lbs worth of battery (especially when heaving them up onto shelves !)
Why clear top ? Easier to look inside, thinner than 3/4" ply ! and when on shelves, you want to make sure there is no chance of something / anything getting into the battery pack, bugs, rodents, errant bits of metal (oopsie protection) etc. Can't be too safe with the amount of juice sitting there.
 

ArthurEld

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Mine may not be as pretty as the aluminum ones but I'm a wood guy. I built boxes just wide enough for 2 cells snuggly. Then an extra 2 inches beyond 4 cells deep. I cut a spacer plate and 2 wedges just tight enough to tap on with my palm when the cells were new and not charged up.
Bms is mounted to the spacer between the wedges. It works, they're heavier then I expected at 8 cellsView attachment 27577
It looks well thought out and functional. It's a battery. I like the Plexi glass cover idea.
 

Greybeard

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Well done, I see you thought ahead and put handles into the sides. Wee detail hat many leave as an after thought after some Blue Air is generated.

I'm also a Wood Guy, similar to your idea but I have hinged Clear Polycarbonate tops and heavy handles on the sides.
Sure makes things easier trying to heave about 40-44kg / 88-97lbs worth of battery (especially when heaving them up onto shelves !)
Why clear top ? Easier to look inside, thinner than 3/4" ply ! and when on shelves, you want to make sure there is no chance of something / anything getting into the battery pack, bugs, rodents, errant bits of metal (oopsie protection) etc. Can't be too safe with the amount of juice sitting there.
I'm going to put lexan on them.
I underestimated how heavy these buggers would be. I may build a new heavier set of boxes with heavier handles for sure
 

SherylinRM

GO GO JUICE BOOMER ZOOMER MAKER
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Mine may not be as pretty as the aluminum ones but I'm a wood guy. I built boxes just wide enough for 2 cells snuggly. Then an extra 2 inches beyond 4 cells deep. I cut a spacer plate and 2 wedges just tight enough to tap on with my palm when the cells were new and not charged up.
Bms is mounted to the spacer between the wedges. It works, they're heavier then I expected at 8 cellsView attachment 27577
A woodworker myself and it is how I made mine as well. :)
I made two 4 cell boxes though.
Getting old and losing strength. I expect to be as strong [weak?] as man by the time I reach my 80's :p LOLOL 😁
Good job. :)
 

Steve_S

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I'm going to put lexan on them.
I underestimated how heavy these buggers would be. I may build a new heavier set of boxes with heavier handles for sure
This is what I ended up with.
The pair of 24V/175's and that's one of my 280's
2x-175AH-8S with QNBBM-8S.jpg 280AH-with QNBBM.jpg

This is the actual Optix Product I used, which I bought on sale at HomeDepot. I bought a large sheet, so after making my "tops" I had plenty left for another project, not cheap :-( but dang, tough stuff the 10mm which I got.
 

Ampster

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Here is a closer view of the top of my pack. The acrylic top rests on the 8 studs and is fastened with 3 socket head cap screws. The BMS is an Overkill and can be monitored from a cell phone. The next iteration I might mount the BMS on the top of the acrylic along with the laptop power supply and CCCV voltage converter that regulates charging (not shown in pictures).
 

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Greybeard

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I was going to build a 16 cell box. Glad I didn't lol. I'm going to make some new ones, maybe on wheels. These have to fit into boxes to ship over to the Philippines and these 8 cell boxes may be a bit too heavy I don't want them to destroy the boxes. I was thinking of lining the inside of the total box with 1/4 in plywood to keep it supported. Weight is unlimited it just needs to hold up.

Looking at the packs with just ends and the rod I may do 4 of them and make them modular so the stack and then I can add my 8s overkill bms's
 

Bob B

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Solarfun4jim

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For all those who are actually interested in the idea of using springs to optimize cell / pack compression, I have started another thread. That way, those who are not interested or think it is a bad idea won't have to suffer through more posts about how to do it or see pics from those who have done it.
The new thread is over here .... https://diysolarforum.com/threads/pack-cell-compression-optimized-by-using-springs.14751/
I was one of the culprits(not deliberate) that perhaps took the thread off course a little....i apologize. I offered an opinion on how difficult i thought it would be to control all the variables, and rather than simply talk down the idea, i offered my solution to the the issue.
Will try to stay on track more in the future. :)
 

Bob B

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I was one of the culprits(not deliberate) that perhaps took the thread off course a little....i apologize. I offered an opinion on how difficult i thought it would be to control all the variables, and rather than simply talk down the idea, i offered my solution to the the issue.
Will try to stay on track more in the future. :)

I don't think any opinion posted on this thread is out of line .... not need at all to apologize. This thread has a LOT of opinions on the subject of cell compression, so I don't see any post as being out of line.

I just thought it would be good for those who are interested in the idea of using springs have a separate thread specifically for that idea.

I'm sorry if I presented the idea of a separate thread incorrectly.
 

Jeremiah

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Mars
Basen said the Lishen are normally 272ah, but a 'good matched' set will deliver 280ah. The EVE are 280ah normally. I'm guessing better quality/standards, but who knows. Specs even put the Lishen's 3mm or so taller. I'll post what they say about the grades.
I've bought both. Recently got some Lishen's in; they look (cosmetics only) better than the 280 Eves I've used.
I haven't tested the Li shens yet but I was really impressed at the presentation.
 

stobbie

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Aug 25, 2020
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I've 3d printed end plates for my lishen 273A batteries. I've compressed the cell bij tightening the thumbscrews I've printed by hand at 50% SOC.
The end plates have 20% infill, so they are a little bit flexible.
When I charge to 3.4v you can hear the plates are being compressed.
20201216_182727.jpg
 

Dzl

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I am bitterly jealous of 3 groups of people here:
1. Y'all with 3D printers
2. Y'all with the skills to program shit to make it do what you want
3. Y'all with a deep understanding of the fundamentals of electricity
😄
 
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