6 AWG cable to QUCC bms?

[DefconExile]

Just a quick one wondering if anyone can help , here I’ve got some 6 AWG cable and I’m trying to determine the best way to connect it to my BMS. Would it be easier if I bought some crimp connectors and bolted it to the bms through the hole or is it still more ideal to solder it? Thanks!

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[DefconExile]

hoping it will look a little something like this. Any feedback?


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[CONSIDERABLE SHOUTING]

I believe bolting is better than solder, but I am only parroting opinions I've heard and I haven't built one yet.

 

[DefconExile]

I believe bolting is better than solder, but I am only parroting opinions I've heard and I haven't built one yet.

Thankyou , I’d assume so too and judging by another post on the forum it’s a common technique for thicker gauge wires , thanks again!


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[amberwolf]

Assuming a proper crimp to the ring terminals, bolt on ring terminals is a better option (more easily repairable as well).

 

[DefconExile]

Assuming a proper crimp to the ring terminals, bolt on ring terminals is a better option (more easily repairable as well).

Great news , I’ll pick some up and use a washer to rise the terminal slightly to keep it away from the PCB , thanks for the info


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[amberwolf]

, I’ll pick some up and use a washer to rise the terminal slightly to keep it away from the PCB , thanks for the info

It is much better to have the ring terminal directly contact the PCB pad. A washer will add resistance to the connection, and if it is not the same metal as the ring terminal and PCB pad, it will also have galvanic corrosion over time.

A washer can be used between the bolt head and the ring to provide more even pressure over the ring surface to press it against the PCB pad, if the bolt head isn't large enough to do this on it's own. A lockwasher (between bolt head and flatwasher) could be used if necessary to ensure vibration/etc can't loosen the bolt, as well, if there is sufficient bolt length to accomodate that.

If there is a spacing problem, such as in the picture in your post like this:

where the terminal may contact things it shouldn't like the heatsink, you can use a different shape or size of terminal, or put it at a 90 degree angle from the way it's shown in the pic so it comes off the side instead of over the top, etc.

Regarding the terminals, make sure you get ones with the right size lug for the gauge of wire you're using. Too large and it will not crimp together as well as it should, too small and you have to leave strands of wire out of the lug. The ring hole should be as close to exactly the size of the bolt as possible, and the ring's outer diameter should be as close as possible to the PCB pad size, so that as much surface area of the two will be in contact for best conductivity.

Regarding crimping the terminals on, there are different kinds of crimpers for different kinds of terminals; make sure you get the right kind to fully crimp the terminals onto the wire such that it turns the entire thing into a single piece of cold-welded metal. Ratcheting crimpers are good if you don't have hydraulic ones--that way you can apply pressure and release but the crimpers won't let go, then squeeze again, repeating as much as needed until the crimp is complete and the ratchet releases.