Which crimp connectors?

[EEnginerd]

We could get into the nationalism / Amazon / corporate-America / buy-local debate on like 90% of the threads on this forum. That doesn't mean that we should do that. In fact, please don't! And, I am not saying I'm a saint in this regard either, but let's all try to move in that direction.

I came in here to get advice on which ring connector to use for my Overkill BMS, so you can imagine my dismay to see that the thread had degraded into a shouting match about buying American and how non-American crap sucks. You all make some valid points that I can agree with, but if we really want to advocate for good manufacturing jobs, we shouldn't be arguing over 10 cent connectors that probably won't add much to our economy anyway. We should be debating why we don't have local manufacturing of the higher value items that all of us on this forum are buying, such as BMS electronics and LFP batteries. Also, grid scale energy storage is going to grow exponentially in the next decade and the US should be trying to locally capture as much value as possible from that supply chain.

Now to bring the thread back on topic, what's the conclusion for the connectors? I believe Overkill BMS uses 24 gauge balance wires and my batteries have M8 studs. I'm leaning toward getting red 18-22 gauge heat shrink terminals. I don't need more than one for each of the 8 balance leads + a few spares, so not a big variety pack. Do you have a preferred source for the connectors? This is my first pack and I don't have any gear at all, so do you also have recommendations for a heat shrink connector crimper and a heat gun?

 

[Deleted member 23531]

I believe Overkill BMS uses 24 gauge balance wires and my batteries have M8 studs

Most cells are M6 studs (1/4"). I know my EVE cells were. I believe the sense leads are 22ga, but I can double check.

 

[Deleted member 23531]

I believe the sense leads are 22ga, but I can double check.

Overkill's PDF says 26ga actually, given this is in their tool list:

• Wire strippers, capable of stripping 26 AWG, Klein Tools 11057 or similar (needed to strip the
  balance leads)

I don't know if you can find 26ga, 1/4" connectors, although in my experience the smallest ones that are widely available (ex: 16-22ga) work fine. You can double up the wire as was previously suggested, or just solder them, or crimp then solder.

 

[toms]

Ignoring the dribble.

The point with thin balance leads is that the most likely failure modes are poor crimp, or wire breaking due to movement.

That is why i avoid the insulated crimp terminals or solder, and use open barrel crimp terminals with glue filled heatshrink to support the wire.

Using insulated terminals makes it very difficult to see if you have a good crimp with the small gauge wiring.

 

[EEnginerd]

Overkill's PDF says 26ga actually, given this is in their tool list:

• Wire strippers, capable of stripping 26 AWG, Klein Tools 11057 or similar (needed to strip the
  balance leads)

I don't know if you can find 26ga, 1/4" connectors, although in my experience the smallest ones that are widely available (ex: 16-22ga) work fine. You can double up the wire as was previously suggested, or just solder them, or crimp then solder.

For 26 gauge in 16/18-22 connectors, I probably will go the route of soldering them to be safe. For soldering, is the correct practice to use an insulated crimp terminal (not heat shrink) that exposes the wire on the ring side? I've looked but haven't found anything that's specifically made for soldering.

Mine really are M8. They're the Coslight cells that Michael Caro recommended in his thread.

 

[Deleted member 23531]

For 26 gauge in 16/18-22 connectors, I probably will go the route of soldering them to be safe. For soldering, is the correct practice to use an insulated crimp terminal (not heat shrink) that exposes the wire on the ring side? I've looked but haven't found anything that's specifically made for soldering.

Mine really are M8. They're the Coslight cells that Michael Caro recommended in his thread.

If you're referring to melting the red insulator from soldering: I removed that, soldered, then put heat shrink over the whole thing. I don't know that it is "the correct practice", it probably isn't, but it worked well and I'm happy with how firmly the wires are held in there.

 

[Zwy]

Strip twice the length and fold the wire over.

 

[Matty-Lee]

Are those 280 A cells? The bus bars look flimsy.

200ah, the ones that came with it.

 

[Matty-Lee]

Anchor "red" for 1/4 studs should work. The red is the smallest.

Great, thanks.
I have some red but too small. I didn't know the size of the ring came in different sizes.
Searched ebay for M6 size and there they are.

 

[Matty-Lee]

The busbars may be temporary for balancing.

When you go to crimp the lug onto the wire, you can strip 1" then fold that in half and see if it will still fit inside the lug, for good bite. You can use shrink tube if you care to.

Great, thank you.

 

[Matty-Lee]

TE Connectivity, for one, makes M6 ring terminals for wire as thin as 22AWG. The screen capture below is from this Newark page for a TE Connectivity M6 for 20AWG. What gauge is your BMS wire?

I found that from a quick search on Newark's site. I'm sure that you'll also find this stuff on Mouser and other major electrical supply sites.

View attachment 47845

Thank you.

 

[Matty-Lee]

Oh boy, I've only posted to this forum twice so far and each time there's been a bit of a fight. ?

 

[Boondock Saint]

It's you Matty-Lee, you look like Ricky Gervais and you just stir controversy and chaos wherever you go. :D

Kidding aside, I agree with you, things have been a little over-arguementive as of late So much ado about a simple ring terminal.

 

[Supervstech]

This thread is under review. Far too much bickering back and forth, political posting and argumentative name calling.