A bolt by any other name, is still a bolt

time2roll

Photon Sorcerer
OK the bus is already copper, the terminal is already aluminum. I think I am using the goo even if stainless is involved.
 

Gazoo

Dumb Dumb
I could use threadlock to the extent it doesn't affect the battery thread to screw current contact area.

I probably won't use a torque wrench on the flange nut, just "prett damned tight" and some threadlock and call it good. 64 times . . .


.
Stainless steel is a very poor conductor. No need to worry about the grub screw making contact with the threads in the cells terminals as far as carrying current. You could use plastic grub screws and it would't matter. The current is carried through the busbars.

No more than 4nm torque is recommended. People have stripped the threads with not much more torque than that.

Personally I would advise against using a threadlocker on the nuts. If you have to remove them for any reason a thread locker could cause problems. People have used regular nuts in mobile environments without a thread locker and the nuts never came loose. But serrated flange nuts are the way to go IMO.
 

Boondock Saint

Solar Addict
I could swear I saw a posting where someone said to stay away from the serrated flange nuts.

I semi agree with you, path of least resistance an all, but since the screw is a conductive metal and it is also touching the nut which is touching the busbar, I'm not convinced that it's a worthless surface area. Since I discovered that the world is really flat after all, I pay attention to these things. :D

So I changed the product to this > https://www.boltdepot.com/Product-Details.aspx?product=12009

You owe me $8.90 for the price difference :D

It seems like the construction method is now to set the screw with </= 4nm torque and use some threadlocker. Wait for threadlocker to set.

Finish by applying serrated flange nut with </= 4nm torque.
 

time2roll

Photon Sorcerer
See and that is part two of my plan in increasing the fastener conductivity. With the additional conductivity I will be closer to 25 inch/lbs. I know that is less than the accepted normal solution but that is how I roll.
 

Boondock Saint

Solar Addict
I literally do not understand any of your past post. There must be some inferences, but they are lost on me, and this isn't my main drinkin night.

You switched to fastner conductivity when you say it isn't important, you switched to inch/lbs from Nm, and you're doing something thay isn't the norm, but not referencing the norm . . . screw it, back to drinkin.
 

Boondock Saint

Solar Addict
Righto, no way I want to over torque the screws.

I'm searching for a relatively inexpensive and small 1/4 torque wrench, preferably one with a digital display. A lot of them don't have the range down to less than 4nm
 
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time2roll

Photon Sorcerer
Presa 1/4" drive torque wrench at Lowes.com works perfectly. 0-9 Nm. 0-80 in-lbs
Sorry not digital and no click. $25 shipped to local store. (US)

14676308.jpg
 

Gazoo

Dumb Dumb
I literally do not understand any of your past post. There must be some inferences, but they are lost on me, and this isn't my main drinkin night.

You switched to fastner conductivity when you say it isn't important, you switched to inch/lbs from Nm, and you're doing something thay isn't the norm, but not referencing the norm . . . screw it, back to drinkin.

4nm is equal to 35 inch pounds which is equal to 700 pounds axial force. That's quite a bit of clamp force applied to the terminal. It doesn't take much torque to provide a good electrical connection between the busbar and terminal provided the cells terminals and busbars are clean, and the busbar is lying flat against the cells terminal. Some corrosion inhibutors will also help electrical connections.

Torque discussion started on this forum when several people stripped the threads in the cells terminals. Some cells come with sloppy or slightly sloppy tapped holes. The fact thet the aluminum cell terminals are very soft is not disputed. If I had to do it all over again I would consider using standard JB Weld because it has a high tensile srength. I used red loctite and didn't realize I should have used a primer with it until it was too late. I have since learned Loctite makes a permanent thread locker that doesn't require a primer.

It's good the newer cells are now coming with laser welded studs which eliminates all of the above concerns for those receiving those cells.

Dont torque the screw. Just run it all the way to the bottom and back off a quarter turn for safety.
I hope everyone is aware we are talking about the torque applied to the nut if using grub screws and nuts and that's what is being discussed.. :)
But you might not like the price.
I have read bicycle torque wrenches are good for this application. However most come with only one torque setting.

Presa 1/4" drive torque wrench at Lowes.com works perfectly. 0-9 Nm. 0-80 in-lbs
Sorry not digital and no click. $25 shipped to local store. (US)
That's what I have... a beam torque wrench. It's big and bulky but works.
 

Gazoo

Dumb Dumb
I think this thread covers the torque thing. I did want to add that no matter what threadlocker one uses some will ooze up to the top of the terminal. Just keep wiping it off. I used a paper towel.
 

zzyzx

Apprentice Neanderthal
I used red loctite and didn't realize I should have used a primer with it until it was too late. I have since learned Loctite makes a permanent thread locker that doesn't require a primer.
Are you referring to Loctite 263?

Loctite 263.JPG
 

BobR

Solar Enthusiast
I dunno bro, I'm getting a bad oxidation / corrosion / reaction / petina vibe there.

I'm sticking w the SS and calling it good without smearing that goo on it.
I used 6mm all-thread stainless steel rod cut to the correct length and then flat washer, lock washer, and a nut. That way you utilize all the threads on the cell; loctite them in. The current is passed through the flats on the terminal.
 
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ken morgan

Solar Addict
Presa 1/4" drive torque wrench at Lowes.com works perfectly. 0-9 Nm. 0-80 in-lbs
Sorry not digital and no click. $25 shipped to local store. (US)

14676308.jpg
sorry but something like that is probably not accurate enough at the lower end to want to use on our batteries. remember a beam type torque wrench is only truly accurate in the middle of its range, so the 1st quarter 0-20 the range we are concerned with is probably 5-10% out of spec. as well as the last quarter of the range. better to get one with a smaller range that places the actual torque you want in the middle of the range for accuracy.
 

time2roll

Photon Sorcerer
sorry but something like that is probably not accurate enough at the lower end to want to use on our batteries. remember a beam type torque wrench is only truly accurate in the middle of its range, so the 1st quarter 0-20 the range we are concerned with is probably 5-10% out of spec. as well as the last quarter of the range. better to get one with a smaller range that places the actual torque you want in the middle of the range for accuracy.
So 4 Nm in the scale of 0-9 is not close enough to the middle?

10% out of spec? So I might be 3.6 or 4.4 Nm? I read beam style is closer to 2% compared to clicker at 4%.

I think I am OK. I believe this Presa torque wrench works perfectly well for these batteries.
 
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