JK-B2A8S20P-H BMS, how large a cable lug can it take?

[MalBurn]

Hello there,

I was wondering if anyone has had any success fitting a larger cable, than the 2x supplied 16mm2/7awg that come with the
JK-B2A8S20P-H?

I'm thinking of running my pack outputs to an Anderson connector and wondered if a two single 50mm2 could be used,
in place of the pairs at p- and b-?



Loving the JK so far.
Thanks for any advice in this area.

 

[fdom]

Why 2 times 50mm2. The BMS is specified to 200A. 25mm2 ring lugs fit. This is what I use.

 

[meetyg]

Please make sure that the ring lugs don't touch the FETS right next to them!

If your lugs do, you basically have two options:
1. File the top of the lugs a bit, just so they don't touch the FETS.

2. Use some sort of insulation material between the edge of the lugs and the FETS.

I opted to put insulation (EVA foam) between the edges of the lugs on my JK BMS, just for extra safety, even though my 25mm^2 don't actually touch the FETS.

 

[MalBurn]

Please make sure that the ring lugs don't touch the FETS right next to them!

If your lugs do, you basically have two options:
1. File the top of the lugs a bit, just so they don't touch the FETS.

2. Use some sort of insulation material between the edge of the lugs and the FETS.

I opted to put insulation (EVA foam) between the edges of the lugs on my JK BMS, just for extra safety, even though my 25mm^2 don't actually touch the FETS.

Thanks for that, yes, I noticed clearance is tight mostly on the output side of the bms.
That’s in part why I’m asking, I’ll file down the ends of the lugs and check it carefully, cheers!

 

[chrisski]

For tight connections a regular lug and a 90 degree lug my fit. I’m unfamiliar with the stud / bus you’re attaching it to

 

[rhino]

Remember, the insulation on those cables are rated for 200C so it isn't going to be necessary to replace them.. Just attach your larger cable to the end of the supplied cables.

 

[MalBurn]

Why 2 times 50mm2. The BMS is specified to 200A. 25mm2 ring lugs fit. This is what I use.

I’m planning to use 1x 50mm2 at each side of the bms and go direct to the neg pin of my Anderson, avoiding any extra connections (on the output side) I would have to make, if using the 2x short 6” cables that came with the JK.

I have a lot of spare 50mm2 and quality lugs lying around, so over speccing the cables will cost me nothing, I’d need to buy in 35mm2, so I wondered had anyone used large cable sizes.

 

[rhino]

Also see this post: https://diysolarforum.com/threads/jk-bms-mounting-position.48565/post-617640

Just tie the two cables coming out of the BMS together and attach whatever cable you want to end. In his case he used butt connector and if done correctly should have negligible affect with regard to resistance due to "another connection".

 

[rhino]

Other option is to put lugs on both cables on BMS and whatever lug you want on cable you want to use and put all three lugs on a single post stud, bolt together, or whatever.

 

[RV10flyer]

Hello there,

I was wondering if anyone has had any success fitting a larger cable, than the 2x supplied 16mm2/7awg that come with the
JK-B2A8S20P-H?

I'm thinking of running my pack outputs to an Anderson connector and wondered if a two single 50mm2 could be used,
in place of the pairs at p- and b-?



Loving the JK so far.
Thanks for any advice in this area.

I use 2 ga splice crimps to connect two 7ga with my short lengths of 2 ga wire.

 

[hwse]

I used a couple of #2-gauge wires with 1/4" ring terminals crimped with a hydraulic crimper. I could have gone larger because you can get 2/0 in 1/4" ring terminals. I chose 2 Guage because two #2 have the exact same cross section as a single 2/0 which is what the rest of my system is built around.

 

[MalBurn]

Other option is to put lugs on both cables on BMS and whatever lug you want on cable you want to use and put all three lugs on a single post stud, bolt together, or whatever.

Thanks for that suggestion, yes, I could use a bolt and connect the 2x 7awg to a larger cable. That's another solution to consider.

 

[MalBurn]

I used a couple of #2-gauge wires with 1/4" ring terminals crimped with a hydraulic crimper. I could have gone larger because you can get 2/0 in 1/4" ring terminals. I chose 2 Guage because two #2 have the exact same cross section as a single 2/0 which is what the rest of my system is built around.

Thank you for sharing that.
So you've had no problems with clearance between the mounting and the mosfets using the 1/4" terminals?
My 55mm2 cables are 1/0 if I'm looking at the right conversion charts, so should fit in a 1/4 copper lug.

Looking at the JK closely, it looks like the terminal mounting for the cable lugs, sits higher than the mosfet legs, but I might try taking off the rounded top of the lug, just to be sure there is a very definite gap. The other suggestion of connecting the JK cables to a larger cable with a bolt, or splice is another idea I'll look at.

 

[MalBurn]

Also see this post: https://diysolarforum.com/threads/jk-bms-mounting-position.48565/post-617640

Just tie the two cables coming out of the BMS together and attach whatever cable you want to end. In his case he used butt connector and if done correctly should have negligible affect with regard to resistance due to "another connection".

That's great, just read the post, thank you