Here’s mine. I don’t remember what size I used but I crimped mine using a hammer and chisel, then used electrical solder to make sure I had a perfect connection
I learned from a NASA guy, and offroad racer mechanics, that you don’t use solder if there’s going to be any vibration. It forms a stiff edge which has no motion on one side and movement on the other so fractures happen at the bend plane. Crimp only and strain relief are best for stuff like automotive systems.
Since you did solder, I would add lots of strain relief to keep the wire from moving at the solder joint.
Makes sense, I will check to see if I can do anything to limit/minimize vibration and movement next time I’m in the battery box. My thought and also what I was told, was to solder them so the cables wouldn’t make their way out from vibration and movement but I completely agree with what you said, we are all aware of how easy copper will work harden.
don’t use solder if there’s going to be any vibration.
I heard this from a Douglas guy too. You will not find a soldered connection in any aircraft wire harness. They also bundle and tie down their harnesses annoyingly well.
You can take tips from them, or not. Then come back here later and ask why your car glitches every time you hit a bump in the road.
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I have Always solderd I’ve never had any issues with any of them & I’ve done probably 500 or more battery cables. Yes cable Management is important. I used to use the Big ass cable Crimper and B4 that I used to use the Smash crimpers, the kind where you had to have the cable in the Crimper and hit it with hammer.
They now have hydraulic crimper’s.
What’s another crimper or two, or 3? And gorum can’t find my darn Klein crimper I’ve used for making Ethernet and coax cables. Bought jaws to crimp BMS sense cables eyelets and still stuck without a crimper!
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Quit crimpin’ my style man…
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How would you guys handle this? The batter modules have large bolts for power attachment and small screws for the middle of cells sensing. See both pics where I show the screws with the ring lugs which fit the screw size and the pic where the sense wire is in the larger Ring lug.
I feel the wire will crimp the small lug fine( when I find my Kleine crimp handle ) but the larger Ring will likely not hold either the wire nor the insulation well at all.
I afraid I may have to drill and tap each bus bar for an M3 screw so I’m only dealing with a large lug at the ends of the battery pack. yuck!
Strip extra bare wire & fold it back on itself so there is more wire to grab when crimping.
Alternate method, fold the bare wire back on the insulation & crimp both in the terminal
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I was thinking of that but didn’t like that the gripping of the insulation wouldn’t be addressed. I was thinking of adding heat shrink along with the folding of the conductor trick. But I think the real/best solution is threading all the buss bars and using all the same size(small) ring terminals and proper crimping. I’ve got 2 drill motors so will have the tap drill in one and the tap in the other. I’ve got a ton of SS M3 screws from all the 3D printer builds I’ve done so should have all but the crimping done today.
Dave and I disagree on folding the wire over the insulation and crimping. I use it for small balance wires, he doesn’t like it.
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Dougl, why is there a sensor wire on both sides of the busbar?
@LithiumGods when I made that pack I split one Gen3 Leaf module in half and the last battery in the picture is that 1/2 module. As such I have custom monitoring boards(in blue 3D printed cases) which mount on top of each 4S battery module. The half module monitoring board and case is out of sight but you can see the sense wires.
Where you can see a full blue box with circuit board, that is mounted to the last full battery module which itself is made of 2 2S modules.
The custom wireless battery monitor boards also top balance and you can see the short harness each of those monitoring boards has for sensing. Also each battery monitoring board is independent of the other. I uploaded sequence numbers to each firmware loaded on each monitoring board and the head unit iterates through the list of modules reporting to it.
It’s a neat setup for monitoring and top balancing can handle upto 3A of bleed-off current but it has no ability to monitor charging, nor disconnecting the charger. The head unit was designed with a CAN interface and this system was designed to be put into a full size EV conversion.
I have no problem with that. As long as the double bare wire is crimped in the conductor crimp and the insulation plus bare wire is in strain relief portion.
It would never fly on the space shuttle, but bI can’t see a failure point.
Also, solder is ok, as the insulation crimp takes care of vibration. IMO.
My point with LG is that a conductor crimp with insulation in crimp is not something that I would do or recommend.
Ps.
I have done similar to use terminals that are oversize for conductor.
- Push wire through terminal.
- Solder to flat of terminal eye.
- Lightly crimp insulation. Or skip if a good fit through tube.
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I agree as long as you can keep the solder from wicking up into the insulation since it can’t be anywhere near the end of the holding crimp or it’ll crack in the insulation.
I do the double crimp thing on projects around the house and at maker spaces but stuff on cars, etc I just don’t like it and I’ve tried to utilize proper crimping tools and techniques when I can.