To make sure we are on the same page, the threads in my cells were not tapped all the way to the bottom. There was quite a bit of space between the the bottom thread, and the bottom of the terminal. I would be willing to bet all of the threads were engaged. But I will call the bet off since that stud is holding so far with the JB Weld...lol.
Cell terminal bolt torque - you might be wrong!
- Thread starter cinergi
- Start date
You are probably correct. Does that change anything? I’m pretty sure the plating on the busbars and the lugs is the same (looks the same).
Does Tin plating interact with zinc-plating?
Where’d you purchase your cells from? Mine seem to go all the way to the bottom (5 full threads). I suppose I could measure to be sure (feeler gauge versus threaded bolt).
zzyzx
Apprentice Neanderthal
- Joined
- Aug 20, 2020
- Messages
- 109
As I await delivery of my Lishen 272 cells, the thought of stripping a terminal thread scares me, as I read what has happened to others. The following video shows a HeliCoil being inserted on purpose (10 sec point) into a "virgin" tapped hole. This was meant to strengthen the aluminum threads before first use. To my simple mind, this makes sense doing before I even put a grub screw in the first time. Thoughts?
Question: How do you remove the tang without damaging the cell? Leave it or use "tangless" coils?
Question: How do you remove the tang without damaging the cell? Leave it or use "tangless" coils?
So zinc-plated studs against tin-plated busbars is a bad idea?
Would stainless grub screws be better? (So stainless against tin)
I’m not understanding what you mean by ‘jacked out’ - are you talking about purposely stripping out the remaining aluminum thread?
Does JB Weld require a particular volume / space to be effective (so it will not weld a grub screw into an intact thread as effectively as Loctite?
if this is correct, I think I’ll start with Loctite and save JB weld for any terminals that strip.
Even my ‘stripped’ terminal (which was stripped with an apparently-undersized bolt) has 3 partial threads and 2 unused / pristine threads, so I think I’d rather try holding with those existing threads as well and save further thread removal for a recovery step in case the remaining threads prove insufficient for the task.
Get the idea but don’t understand whether this needs to be done for the initial use of JB Weld in a threaded terminal or only if/when grubscrew removal and replacement after attachment with JB Weld ever proved necessary...
ArthurEld
Solar Wizard
Adding helicoils from the start is a good idea. I wouldn't leave the tang on or in the hole.
Don’t Helicoils remove close to half the Aluminum contact area? You guys are not concerned about that?
schmism
Solar Addict
I thought we established that the area of effective contact was the underside of the cable lug and the surface it touches. Only minimal amount current is passed through the hardware via the threads.
Yes, I remember (and that is the reason I’ve been concerned about the Helicoil).
He seems to be implying that the pier surface of the Helicoil is flat and co-planar with the surface of the terminal, and so ‘counts’ in terms of the surface area contacted by the lug or busbar...
Glad to hear there may be some hope for your terminals without having to use a drill/tap to make a larger hole. Somebody tried to save money on screws that aren't as wide as they should be.
As far as a reason to back off of the bottom of the terminal hole, do that if you're not sure you can solidly hold the grub screw from turning while you tighten the nut. It gives you a little room for error. If I was using grub screws, I would want them to have hex tops, not slotted (screwdriver) tops.
Check a galvanic series table to see how bad it is. It may be fine, it may be bad.
Certainly not half.
You're splitting hairs ^^ (and that comes from someone who is usually the one splitting hairs...)
The lost area is very small, don't worry about it
Thanks.
And yeah, I’m leaning away from aluminum or plated and back to stainless (hex) grubscrews.
And if the only reason to back off is a safety margin, I’m probably more concerned with using maximum remaining aluminum thread for strength than I am for margin in case the Loctite doesn’t hold.
I’ve used Loctite before but never JB Weld. One poster is making it sound like JB Weld needs the aluminum threads removed before it can be used. If that’s the case I’ll start with Loctite and save JB Weld as a fall-back in case the remaining threads don’t hold...
My EVE cells came from Basen. I purchased them from the group buy thread.
ArthurEld
Solar Wizard
How about this? https://supergluecorp.com/product/red-permanent-threadlocker/
ShenzenBasenTechnologyCo is where my 280Ah cells came from as well (direct, didn’t know about a group buy).
If our thread depths truly are different, it’s pretty much affirmation that resellers / trading companies like Basen purchase their EVE 289Ah cells from multiple wholesalers / middlemen and also that the aluminum terminals are tapped by those middlemen and not by Shenzen themselves...
Interesting. How are you thinking this would compare to Loctite and/or JB Weld?
Stronger and more permanent than Loctite but compatible with remaining threads (compared to JB Weld which may not be)?
Do you know if anyone on the Forum has used this on M6 aluminum terminals yet?
ArthurEld
Solar Wizard
I am trying to figure out which one strengthens the threads the most
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