LiFePo4 bolts

[MartyByrde]

Hi I lost two of the bolts for my 16s LiFePo4 battery. Are these M6 bolts safe to use? They aren’t flange bolts and have a black rubber lining. The left is what I bought and the right is what came with the cell for comparison.

 

[Samsonite801]

You could use them, but I would throw a flat washer underneath it (one with good fit around the stud, not all sloppy and loose)...

 

[MrThisIsME]

You could use them, but I would throw a flat washer underneath it (one with good fit around the stud, not all sloppy and loose)...

^ what he said.

I would use them until I found a replacement flange bolt.

 

[MartyByrde]

Thanks guys

 

[MartyByrde]

You could use them, but I would throw a flat washer underneath it (one with good fit around the stud, not all sloppy and loose)...

Should I remove the black rubber inside the bolt or doesn’t make a difference?

 

[740GLE]

That’s nylon not rubber, and it’s a thread locker, kinda similar to how the flanges nuts bite into the bus bars to prevent backing off.

I’d leave the nylon on there if you have terminals that get hot enough to melt the nylon you have bigger issues you should have been addressing sooner.

If you’re particular about matching hardware a decent Ace Hardware should carry m6 flange nuts in the pick and pay area just gotta hunt for them, if not Amazon can get them.

 

[timselectric]

FYI
If that nylon gets hot, it will weld the nut to the stud.

 

[740GLE]

What’s melting point of nylon? If the terminals get that hot, undoing the bolts is the least of his concern.

 

[BigGun]

If you have those cells with the shallow threads, I wouldn't use those nuts. It takes a little bit of force to push the stud through that nylon (you're basically threading the nylon as you go through it ) Just use standard nuts with a lock washer and flat washer . Then torque

 

[timselectric]

What’s melting point of nylon? If the terminals get that hot, undoing the bolts is the least of his concern.

It doesn't take much, surprisingly. Nylon nuts are spec'd on a lot of work that I used to do. And I had to constantly tell my new guys not to install them with anything other than hand tools. Because turning them on too fast was enough to weld them in place. Then we had to cut them off, for final adjustments.

 

[740GLE]

Don’t think he’s going to be speed threading these on.

Either way we can all agree heat on terminals are bad.

 

[timselectric]

Many reasons for not using them, in this situation.

 

[toms]

Don’t use the nylocs, they are a real risk of sticking on stainless thread, and it isn’t possible to control the low torque you will be needing to achieve.

Plain nuts with serrated washers are the go.

 

[Samsonite801]

BTW, I bought these before on Amazon (Prime One-day):

M6 x 1mm Thread 304 Stainless Steel Serrated Flange Metric Hex Lock Nuts 26PCS: Amazon.com: Industrial & Scientific

M6 x 1mm Thread 304 Stainless Steel Serrated Flange Metric Hex Lock Nuts 26PCS: Amazon.com: Industrial & Scientific

www.amazon.com

 

[meetyg]

I actually broke the aluminum welded studs on some cheap Lifepo4 cells, using these nylock nuts. The problem was that they need more turning force (torque) to tighten them, because of the nylon friction. I used a torque wrench set to about 2 nM (lowest setting), but because these were hard to turn anyway, I really didn't have much feel, and broke the stud. Happened only on the aluminum positive, not the copper negative. So maybe the studs themselves were weak in the first place, but still, I stopped using them. Got myself a pack of flange nuts. Haven't had problems with them.

 

[Goboatingnow]

Hi I lost two of the bolts for my 16s LiFePo4 battery. Are these M6 bolts safe to use? They aren’t flange bolts and have a black rubber lining. The left is what I bought and the right is what came with the cell for comparison.
View attachment 107974

Hi you mention bolts and show a picture of nuts

 

[Mrman1234]

Thread pattern should be 6mm x 1.0mm for larger cells. 10mm length should be fine. You can get packs at lowes or Home depot.
If they dont have a length that short 12mm should be ok. As long as it doesn't bottom on with a gap on the top.
You can always cut them down In a pinch. Just mark the legth needed, put a 6mm nut on 1st, make your cut. Then when you take the nut off it cleans up the threads. You can get a 4 1/2 angle grinder at harbor frieght for $10-15. Discs are pretty cheap.

 

[Goboatingnow]

Thread pattern should be 6mm x 1.0mm for larger cells. 10mm length should be fine. You can get packs at lowes or Home depot.
If they dont have a length that short 12mm should be ok. As long as it doesn't bottom on with a gap on the top.
You can always cut them down In a pinch. Just mark the legth needed, put a 6mm nut on 1st, make your cut. Then when you take the nut off it cleans up the threads. You can get a 4 1/2 angle grinder at harbor frieght for $10-15. Discs are pretty cheap.

In general I would use brass over stainless as brass conductivity is 6-7 times better then stainless. Stainless screws also bind into anything not stainless and unlike brass are a real PITA to drill out.

Brass will be expensive but it’s the best imho.

To me M6 seems a little light , mine has M8 holes. What’s the most common

 

[740GLE]

Current goes from battery terminal to bus bars, you shouldn’t be counting on any threaded insert/fastener to provide additional current flow.

 

[Goboatingnow]

Current goes from battery terminal to bus bars, you shouldn’t be counting on any threaded insert/fastener to provide additional current flow.

Correct but real life things flow every which way hence I want to give my systems done design headroom , brass does that better then stainless