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

BiduleOhm

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If these cells need room for expansion and don't have it due to a fixed compression frame, wouldn't the vents be popping more than a series of wildcat wells that had just struck a high pressure crude oil pocket?

Pretty sure the expansion is because of the material migration and not because of some internal gaseous pressure. But I can be wrong, I'm not specialized enough on that subject to say for sure.
 

conquistador

New Member
Joined
Sep 21, 2021
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(that's my build).
Let me first say that your whole setup looks impressive.
I'm just at the beginning and have crimped a "flexible" connection with cable and lugs today.There I realized that the lugs turn when I move the batteries a bit. (they were not screwed tightly)
Now I feel the need to build a mOhm meter first, as I don't trust the lugs and crimping, and soldering lugs to cable seems to be considered a sin LOL.
Was the resistance the reason why you moved away from "flexible" ?
 

100 Proof

"Please Lord, don't let me do something stupid."
Joined
Feb 14, 2021
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95
Yes almost 100% at 100% SoC gets me the PSI specs I was looking for. They're long springs so even the 16*0.5mm of movement that could occur still gives me great compression at 0% SoC
Just as an fyi, you might want to talk with your spring vendor about the effects of full compression of the springs. Some springs need to be de-rated if they are ever compressed beyond a certain percentage, often 70%. Having said that, we are not exactly building furniture with a spec that has a +/- 50% tolerance.
 

cinergi

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Let me first say that your whole setup looks impressive.
I'm just at the beginning and have crimped a "flexible" connection with cable and lugs today.There I realized that the lugs turn when I move the batteries a bit. (they were not screwed tightly)
Now I feel the need to build a mOhm meter first, as I don't trust the lugs and crimping, and soldering lugs to cable seems to be considered a sin LOL.
Was the resistance the reason why you moved away from "flexible" ?

Thanks! I moved to bus bars due to relatively high resistance (I believe skin effect caused by the AC waveform induced on the battery pack by the inverters) which was confusing the BMS due to wild voltage fluctuations at the per-cell level. Indeed I was also concerned about the rotational force on the terminals as the batteries expanded & contracted, causing the cables to exert different rotational forces on the terminals ... and whether that would cause a problem in the terminal or the connection loosening up. But the main concern was the resistance. I don't think I would have made the change just on the terminal forces concern alone.
 

cinergi

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Pretty sure the expansion is because of the material migration and not because of some internal gaseous pressure. But I can be wrong, I'm not specialized enough on that subject to say for sure.

From what I remember reading, this is correct.
 
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