What is the Consensus on Cell Compression Force on EVE 280ah?

[PeSCaLo]

Hi Guys, After so many Years of testing, what is the consensus on Pressure for Compression on Eve 280 or 300 Cells?

 

[AntronX]

What years of testing? There is no consensus. Another horse beating thread incoming?

 

[S Davis]

What years of testing? There is no consensus. Another horse beating thread incoming?

Yes, good luck with that, I agree just read the numerous threads trying to justify not using compression even though most manufacturers don’t even rate their cells with out it.

I compress my cells, 2.5 years in a rough mobile application.

 

[SparkyJJO]

Consensus? None. Contentions? Plenty.

 

[AntronX]

I compress my cells, 2.5 years in a rough mobile application.

I compress mine as well. For science!

 

[S Davis]

I compress mine as well. For science!

Mostly trying not to burn down my $100,000 work rig drawing 250-300 amps through faulty connections from moving, shifting cells.

 

[Ampster]

I compressed mine enough to not strain the terminals when the cells tried to expand. Proof of the pudding was when I disassembled the pack, after unbolting the bus bars the pack expanded from a few cells which had expanded. I had 48 cells in two rows of 24 which was almost six feet and the entire pack moved 1 1/2 inches. That was three of the 24 cells on one side but a quarter inch per side of the three cells. Initiallly it was five turns of the nuts on 1/4 thread rod. It was a lot more turns to release the pressure. The thread rod was in a lot of tension and I am sure stretched under the load. This is just an explanation of what I did and is no attempt to influence the consensus one way or another. I do believe there was value in compressing that pack. I also believe it would be worthless to argue whether 4 turns or 6 turns of those nuts would have made a difference.

 

[Airstream]

Yes, good luck with that, I agree just read the numerous threads trying to justify not using compression even though most manufacturers don’t even rate their cells with out it.

I compress my cells, 2.5 years in a rough mobile application.

Hey, I am about to build a 8s EVE 280 pack in a 2x4 configuration for my travel trailer. Interested in your experience. I plan on compressing if nothing else just to provide stability in a mobile environment. However, I am afraid of locking them down too tight. I don't plan to put a bottom on the battery bank sandwiched together. They will sit on a plywood floor where I will bolt the whole sandwich down. Hence, I need a decent amount of force, but maybe that is a bad plan?

 

[S Davis]

Hey, I am about to build a 8s EVE 280 pack in a 2x4 configuration for my travel trailer. Interested in your experience. I plan on compressing if nothing else just to provide stability in a mobile environment. However, I am afraid of locking them down too tight. I don't plan to put a bottom on the battery bank sandwiched together. They will sit on a plywood floor where I will bolt the whole sandwich down. Hence, I need a decent amount of force, but maybe that is a bad plan?

I just used four 160# die springs this gives me just under the recommended 680lb on the face of the cells, i also mounted mine on 1” vibration dampers.

 

[HRTKD]

Hey, I am about to build a 8s EVE 280 pack in a 2x4 configuration for my travel trailer. Interested in your experience. I plan on compressing if nothing else just to provide stability in a mobile environment. However, I am afraid of locking them down too tight. I don't plan to put a bottom on the battery bank sandwiched together. They will sit on a plywood floor where I will bolt the whole sandwich down. Hence, I need a decent amount of force, but maybe that is a bad plan?

I used a torque wrench to A) ensure that I didn't put too much force on the cells and B) make sure that all of the threaded rods were under the same tension.

If you don't have a torque wrench, use a nut driver (handheld, not powered). You probably won't put too much tension on the rods by hand. If the cells don't drop out of the compression fixture when it's lifted, it's probably close enough.

 

[Airstream]

I used a torque wrench to A) ensure that I didn't put too much force on the cells and B) make sure that all of the threaded rods were under the same tension.

If you don't have a torque wrench, use a nut driver (handheld, not powered). You probably won't put too much tension on the rods by hand. If the cells don't drop out of the compression fixture when it's lifted, it's probably close enough.

That's my thought, I do have torque wrenches. What torque spec did you use? I see between 5-10 INCH LBS per bolt which seems like nothing to me, but my mind is usually in car bolt torque figures

 

[HRTKD]

It's been a few years, but I think I used 12 inch pounds.

You're trying to get the cells snug but not tight.