How do you know when you’ve pierced a terminal bottom on an EVE 280Ah cell?

fafrd

Solar Addict
I have not personally messed with these threads/cells yet, but my prior experience with aluminum is that it can be prone to sloppy machining resulting is loose tolerance. Thread locker is good at preventing a bolt from turning in the hole, but most flavors are not good at filling gaps and providing additional structure where needed. When my cells arrive, I plan to assess the tolerance and make a call. My preference would be thread locker, but I'll consider an epoxy approach if things are really loose. My batteries are going in a van, so I don't want any questions on torque or reliabilty
That’s a good plan.

I didn’t have the wherewithal to check my thread depth and tightness of fit when my new EVE 280Ah cells came in (too excited ;).

I went straight to balancing and then capacity testing using the bundled busbars and bolts, only tightening by hand/finger, but I now know that means as much as 20 inch-lbs.

Each cell was only threaded and unthreaded 4 times through this process but the bottom line was that after I’d partially stripped a thread torquing to 35 inch-lbs and began planning to convert all terminals with grubscrews, the aluminum threads were all looser than I was comfortable with.

They could have arrived that way from the get-go or galling of stainless bolts in soft aluminum threads may have worn off some thread material and loosened them up after only 4 gentle threadings/unthreadings, but the bottom line is that after seeing how loose they were and discovering how effective JB Weld was, it was an easy decision to use JB Weld on all the loose threads.

I’m also shocked at how much JB Weld ends up being absorbed by the threads. I’m putting in two matchstick-head-sized dollops per thread, and once it starts oozing out, some of that is obviously not staying in the thread, but the total volume of the HB Weld I’m cleaning out around the threads at the top is less than 25% of the volume of what I added at the beginning.

Each ‘dollop’ is probably close to 2 drops worth, so about 4 drops going in and less than one drop coming out.

It’s a pretty painful process - I think it’s taking me about an hour for each cell, but it is very satisfying to see how well it comes out...
 

fhorst

making mistakes so you don't have to...
Personal experience, I've got too deep.
I could tell as there suddenly was no "stop"

I did not go all the way down!

What I did do (with all my threaded rods) is secure it with Locking agent (Loctite) with it, creating a new air tight seal.

If it was vacuum, it would have sucked in "contaminated air".
If it have stable pressure, then "nothing happened)

After 3 months of usage, I can not see or measure any difference between that cell and all the others
(32* 280Ah)

I hope this helps :)
 
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