JK BMS two cables in one lug?

[maschinist]

Hi,
I am changing from a daly BMS to the JK-B1A20S15P. The JK comes with two open cables each for B- and P- with 10mm2/7 AWG.

So I am thinking about whether it's a good idea to put e.g. the two B- cables in one lug (25mm2 should work).
That would make it easier to connect to the fuse/battery/shunt if there ist only one lug.
If I put a lug on each cable I think that could result in a bad connection e.g. on the fuse/battery/shunt because then there lays one lug on another and maybe the holding screw ist too short. (but the crimping of the lug would be "better")


my pro's for seperate lugs:

• better(?)/easier crimping for the lug
• more flexibility with placing the bms in the "battery box" (cables can be moved seperate)

my con's for seperate lugs:

• possible bad connection/high resistance laying lug on lug
• connection screws may be too short (e.g. on a LiFePo4 Cell)
  
• needs more lugs

my pro's for combined lugs:

• easier to connect to fuse/battery/shunt
• "better" connection/less resistance on connection(?)
• needs less lugs

my con's for combined lugs:

• after crimping the cables-lug-combination is not very "moveable"
• possible bad connection (?) on the lug, because the are two cables in one lug

How did you solve this and what is the best/prefered way to do it?

best wishes
Peter

 

[Steve_S]

I had to extend my JK-BMS Cables.
I used 1x 4-AWG Butt Connector which takes the 2x-7AWG wires. Be careful to not fray the edges of the 7AWG, it is tricky.
Then I used 4-AWG Silicone Wire to extend the P- & B- which in turn received Tinned Terminals.
Used a Hydraulic Crimped with 25mm Die.
*RED Silicone wire, was supposed to be Blue but there wasn't enough stock, so it's red.

 

[Skypower]

I went this route. The lugs are Ancor #6 3/8”wide and #6 5/16 wide. I used an AMZCNC 12 ton hydraulic crimper(Amazon) for the small stuff like this and a 16 of the same brand for 2/0 +. The dies edges around the hex I radiused well so as to not pinch off or compromise the lug. First I used the #6 die set then because the wire is actually a #7, I finished the crimp with a mixed set of #8 & #6 dies. The lugs are orientated opposite to facilitate mounting. I used four 3M cable tie mounts hold the bms and space it off to help with convection cooling all around it.

 

[John Frum]

@Skypower Why did you put the fuse on the negative leg?

 

[Skypower]

It was handy.

 

[Skypower]

@Skypower Why did you put the fuse on the negative leg?

 

[John Frum]

@Skypower are you aware that by common convention we fuse the positive lead and ground the negative?
I'm not sure why you are showing me the additional pictures, my eyesight is pretty bad so maybe I'm just missing something.

 

[Skypower]

Made for a nice low attachment point for the bms, convenient space, eliminated another jumper/post. Regardless of where it is, it blows, it’s in the loop and the load out on that battery stops and hopefully the fast blow saves things.