Overkill Solar 4S 12V 120A BMS M6 threaded Terminal wiring question

[forscience]

I notice that the 12V BMS from Overkill Solar has the option to include 3 soldered wires on each side of the BMS or an option to have 2 M6 threaded terminals on each side where the "C-" and "B-" wire holes are left empty.

So if I pick the M6 threaded terminal option, will I need to solder a 3rd wire on each side on the "C-" and "B-" holes or do I just use 2 wires on each side instead of the 3 wires on each side like in the other option? Will there be any difference in functionality?

The 2 different options pictured below:

 

[John Frum]

Simple answer: Just use 2 appropriately sized wires or make a busbar to aggregate the m6 threaded terminals and use 1 appropriately sized wire.

Less simple question: What is an appropriately sized wire?
I will answer if you are interested.

 

[forscience]

Simple answer: Just use 2 appropriately sized wires or make a busbar to aggregate the m6 threaded terminals and use 1 appropriately sized wire.

Less simple question: What is an appropriately sized wire?
I will answer if you are interested.

Thanks for the "simple" answer! And yes, I'm interested in hearing about what you mean by appropriately sized wire. If it's what I'm guessing--I plan to have a max load of 110A on my 12V battery and according to this chart(https://conduit.site/tables/table-310.15-b-16.php) I should go with 2 #6 guage wires on each side of the BMS.

 

[John Frum]

Appropriate sized would mean equal or greater current carrying capacity than the original 3 wire option.
Looks like 3x 8awg pure copper wire with insulation rated for 105 Celsius.
Using this calculator https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html

3x 8 awg = {

1x 3 awg(which is hard to source)​

or 2x 6 awg(which is easy to source)​

}
All of these equivalent options are well above the BMS's ampacity rating of 120amps.

Hope that helps.

 

[forscience]

Appropriate sized would mean equal or greater current carrying capacity than the original 3 wire option.
Looks like 3x 8awg pure copper wire with insulation rated for 105 Celsius.
Using this calculator https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html

3x 8 awg = {

1x 3 awg(which is hard to source)​

or 2x 6 awg(which is easy to source)​

}
All of these equivalent options are well above the BMS's ampacity rating of 120amps.

Hope that helps.

Yes, thanks for clarifying! I will go with 2x 6 awg.

 

[Horsefly]

I notice that the 12V BMS from Overkill Solar has the option to include 3 soldered wires on each side of the BMS or an option to have 2 M6 threaded terminals on each side where the "C-" and "B-" wire holes are left empty.

So if I pick the M6 threaded terminal option, will I need to solder a 3rd wire on each side on the "C-" and "B-" holes or do I just use 2 wires on each side instead of the 3 wires on each side like in the other option? Will there be any difference in functionality?

The 2 different options pictured below:

View attachment 75585View attachment 75586

Minor detail: I am pretty sure the threaded terminals are M5, rather than M6. At least they were for the two 150A 4S that I bought directly from JBD. I figured they were M6 so bought some good quality M6 x 10mm bolts. When the BMS's arrived they didn't fit, so I had to buy M5s.

EDIT: Well, I see that Overkill says they are M6, so I take it back. The ones from JBD were M5, but maybe Overkill puts in their own threaded terminals.

 

[On_The_Road]

I wanted to ask an additional question for this.....

I'm running two 120A Overkills at 12V in parallel. Two 4S 280AH EVEs.

Each BMS will only see half of the total system load. But how does using 6AWG play into my fuse choice for the fuse coming off of the two batteries?

For the two home run positive and negative I'm using 2/0 which leads to a 225A T Class Fuse. This fuse is well over the ampacity of a 6AWG wire.

Is that an issue?