Correct Battery Torqueing???

[HRTKD]

How do you feel about terminal spray post torque on these 280ah batts?

Corrosion inhibitor between the terminal and the bus bar/lug, yes. After install, if the bus bars corrode on any surface other than where they mate with the terminal, I couldn't care less. At that point, it's just aesthetics, not functionality.

If you're using aluminum bus bars against an aluminum terminal, the likelihood of corrosion, due to dissimilar metals, is almost zero. However, if the mating surface is not airtight (highly unlikely that it is airtight), a thin layer of noalox or no-ox-id is appropriate.

 

[time2roll]

I see grade 2 steel M6 torque rated at 3 ft/lbs or 36 in/lbs with 55,000 psi material strength given.
I see aluminum at 42,000 to 14,000 psi.
This on top of a poorly cut thread.

I am no expert on this but it keeps looking like people might be stripping out the threads.... and they are.

 

[jwelter99]

The pole is the entire terminal. It's like an iceberg. There's more below the top of the cell that you can't see. Maybe it's a bad translation to English. Nobody that has any respect for their cell will tighten to 8 Nm.

Thats being a bit of a drama-queen. I ran my Eve 280's at 7Nm for quite some time. Zero issues. No pull out. And plenty of respect for my cells.

I understand some do not have the ability to properly fix their cells if the threading was badly done. So we see people trying goop to solve it, and/or lowering the torque setting.

All this might work, but the risk is that if the threads pull out further you can get oxidation (from not having an oxygen free connection) and when under load terminal erosion. Once the terminal is pitted it's pretty hard to salvage the cell.

As for the ice-berg the cell terminals are fastened to the cell top and they don't want you torquing harsh enough to tear the terminal out of the cell top. The torque you are applying to the bolt or nut is not all transferred to the terminal as the interlinked bus bar will be the friction surface that the nut is rotating against (and they can't rotate due to being interlinked), and the terminal itself will only see a small rotational torque that is transferred down the stud into the terminal. You should never torque a nut down on the bare terminal as it's a sure fire way to hurt the terminal surface and/or tear it from the cell top.

 

[curiouscarbon]

I think they don't specify that because they don't supply them with the threaded terminals .... just a smooth top terminal that can be laser welded or tapped .... I think they are being tapped for or by the aftermarket folks...... I could be wrong.

Smooth top terminal is what I’m under the impression cells look like “fresh” for at least one form factor. Those selling the cells by the sea shore with tapped terminals seem to be buying raw cells flat top and adding tap as value added service.

 

[HRTKD]

Thats being a bit of a drama-queen.

Oh, you wound me! I must take personal offense at such malicious statements. Pistols at dawn can be my only recourse! LOL! Man, only my wife gets to call me a drama queen.

OK, maybe it was a bit dramatic.

I ran my Eve 280's at 7Nm for quite some time. Zero issues. No pull out. And plenty of respect for my cells.

What are you using for a torque wrench?

As for the ice-berg the cell terminals are fastened to the cell top and they don't want you torquing harsh enough to tear the terminal out of the cell top. The torque you are applying to the bolt or nut is not all transferred to the terminal as the interlinked bus bar will be the friction surface that the nut is rotating against (and they can't rotate due to being interlinked), and the terminal itself will only see a small rotational torque that is transferred down the stud into the terminal. You should never torque a nut down on the bare terminal as it's a sure fire way to hurt the terminal surface and/or tear it from the cell top.

Not all terminals are covered by a bus bar. There are two that have a cable lug on them, which certainly can rotate.

 

[Bob B]

Some of the old torque specs actually showed an internal M4 screw instead of the M6 .... but still showed the 8 nm torque for the pole was still listed.

There are several different versions of the EVE spec sheet .... and it's kinda confusing because the newest on is Version A (Dec 2019) .... while the one previous to that Version E (April, 2019)

This is because there is a new generation of the 280 ah EVE cells introduced in Dec of 2019 the 280N .... I imagine that is the cell most if not all are getting now that the old ones have sold out.

The spec sheet for the 280N doesn't even mention the pole torque like the previous ones did .... the spec sheet for the 280N only gives the cycle life specs if compressed to 300 kgf .... it does not include the un-compressed spec like previous .. only different temperatures.

The picture of the cell in the new spec shows a terminal that isn't tapped.

The 280N spec sheet is in resources .... Here..... https://diysolarforum.com/resources/eve-lf280n.139/

 

[Gazoo]

Thats being a bit of a drama-queen. I ran my Eve 280's at 7Nm for quite some time. Zero issues. No pull out. And plenty of respect for my cells.

Anyone can torque to their hearts content and get lucky...as you did. 4nm is enough. You can search for the tables that show it. 4nm is equal to 700 pounds of bolt clamp force. 3nm is equal to 500 pounds of bolt clamp force. There have been too many stripped terminals and using caution is better than ending up with a stripped terminal.

All this might work, but the risk is that if the threads pull out further

If the threads pull out then there will be a bad connection that can get very hot and that's a big no-no. There are several ways to help avoid this:

1: Use a thread locker and use studs instead of screws no matter what condition the cells terminal threads are in. If I had thought of using JB Weld than I would have used that instead of Loctite. I think the standard or original JB Weld has the highest tensile strength of anything I looked at. Loctite that doesn't not require a primer would be a good choice too.

2: Do not torque more than 4nm to 5 nm.

3: Used braided busbars or cables for the interconnects instead of solid busbars.

4: Ensure the cells are clamped securely keeping in mind they will move slightly due to expansion and contraction.

I know there are some who have used the hardware that came with the cells. Screws and solid busbars and have so far have had no problems. I am thinking long term use and am concerned for those using the cells in mobile environments. My cells are stationary and I am still applying the steps I posted.

 

[Gazoo]

How do you feel about terminal spray post torque on these 280ah batts?

I would use something I can apply with a small brush or q-tip to avoid getting any on the threads. Something like this:

Amazon.com

I haven't used anything but when I rebuild my pack I will use something. But not a spray.

 

[Bobs RV 36']

Anyone can torque to their hearts content and get lucky...as you did. 4nm is enough. You can search for the tables that show it. 4nm is equal to 700 pounds of bolt clamp force. 3nm is equal to 500 pounds of bolt clamp force. There have been too many stripped terminals and using caution is better than ending up with a stripped terminal.

If the threads pull out then there will be a bad connection that can get very hot and that's a big no-no. There are several ways to help avoid this:

1: Use a thread locker and use studs instead of screws no matter what condition the cells terminal threads are in. If I had thought of using JB Weld than I would have used that instead of Loctite. I think the standard or original JB Weld has the highest tensile strength of anything I looked at. Loctite that doesn't not require a primer would be a good choice too.

2: Do not torque more than 4nm to 5 nm.

3: Used braided busbars or cables for the interconnects instead of solid busbars.

4: Ensure the cells are clamped securely keeping in mind they will move slightly due to expansion and contraction.

I know there are some who have used the hardware that came with the cells. Screws and solid busbars and have so far have had no problems. I am thinking long term use and am concerned for those using the cells in mobile environments. My cells are stationary and I am still applying the steps I posted.

I like the idea of using original JB Weld as it actually has metal powder in the epoxy. As long as you Applied to the inside threads and not accidentally the face of the terminal. I would think no more than 4nm on stud from the lubricant prop of the epoxy.
Where do you get the braided bus bars?

 

[Gazoo]

I ordered these but I have not installed them yet. The actual length end to end is 4.5 inches. There are many other variations available.

Home page

www.galco.com

Full specs are here:

MBJ Grounding and Bonding Braid, Tinned Copper, 120 A Ampacity, 31.57 kcmil, 3.937", 0.256" Hole

www.erico.com

The cross section is 31.57 kcmil which is almost equal to a 5awg cable.

AWG American Wire Gauge (Gage) Converter Calculator

Since they were so cheap I decided to order enough to double them up.