2 Questions on connecting current carrying wires for JBD BMS - Connection and Amp allowed with two parallel 10 Gauge wire supplied

[tsenator]

I have 2 Questions on connecting current carrying wires for JBD BMS (in this case 100A Smart BMS) -

First Question -- How do you people wire these to the battery terminals or negative output battery post ? They are definitely too short as is to reach the terminals in my case I am using 100+AH prismatic Cells . I've seen some 'shoddy' soldering done by some Will Proust tear downs of batteries. I really would rather have a much cleaner connection. I have quality heavy gauge wire crimpers and I like the neatness of a good compression crimp. But what would I do? Strip back more insulation and double up the two wires into one heavy duty crimp and then use a 2 or 4 gauge wire on the other side ???

Come on people show me pics on how you did this ? Neatness and quality of connections are important to me .

Second question -- For you Electrical Engineers - How much current do these two 10 Gauge wires spec'ed to carry while in parallel ? Do you just add up the cross sectional area of the wires and get the closest wire gauges? 10 Gauge wire has cross sectional area of 5.26mm so doubling that is 10.5mm -- which is close to 7 gauges (Which is speced at max current about 90 A) ? Is that right ?

 

[chrisski]

Second question -- For you Electrical Engineers - How much current do these two 10 Gauge wires spec'ed to carry while in parallel ?

Not an EE, but my 8 gauge wires coming out of my Overkilll ( rebranded JBD) BMS have a 200 degree C insulation printed on the outside. I normally choose wire with an ampacity at 60 C for what I want to make, so 200 C would be significantly higher. I don’t know how high. Because of that high temp rating on the wire, I’d do a lot of research prior to changing.

For the short wires, I would put that on a board above the negative terminal. Two 10 AWG wires would crimp into a single 8 AWG lug. I ordered my BMS with longer cables and that is not that apparent from this pic once it’s before the battery was finished, but here:

 

[tsenator]

Thank you for the pic.

 

[mdatot]

I have 2 Questions on connecting current carrying wires for JBD BMS (in this case 100A Smart BMS) -

First Question -- How do you people wire these to the battery terminals or negative output battery post ? They are definitely too short as is to reach the terminals in my case I am using 100+AH prismatic Cells . I've seen some 'shoddy' soldering done by some Will Proust tear downs of batteries. I really would rather have a much cleaner connection. I have quality heavy gauge wire crimpers and I like the neatness of a good compression crimp. But what would I do? Strip back more insulation and double up the two wires into one heavy duty crimp and then use a 2 or 4 gauge wire on the other side ???

Come on people show me pics on how you did this ? Neatness and quality of connections are important to me .

Second question -- For you Electrical Engineers - How much current do these two 10 Gauge wires spec'ed to carry while in parallel ? Do you just add up the cross sectional area of the wires and get the closest wire gauges? 10 Gauge wire has cross sectional area of 5.26mm so doubling that is 10.5mm -- which is close to 7 gauges (Which is speced at max current about 90 A) ? Is that right ?

For very short cables the limit is the heat caused by losses in the cable, which is a problem mainly in its skin (melting the insulation). That means that unlike in voltage drop calculations, where you add up the cross sectional area as you describe, for heat limits you just add the max rated amperage of each cable together. You can find some tables of heat limits by wire dimension and insulation material in tables published by cable manufacturers, for example: https://www.multicable.com/resources/reference-data/current-carrying-capacity-of-copper-conductors/

Even if you have high temperature insulation though I'd feel rather leery of running over 50A through 10AWG, so 2x10AWG for 100A is really on the bottom end of what I'd consider acceptable, at least if you're planning to actually use all of the available current. For comparison, in marine applications 4 AWG is considered the minimum for 100A of any length, and for 50A it's 6 AWG. If you're not planning to use the full 100A though, don't choose oversize cables just for the sake of it - it doesn't make you any safer, rather the opposite (as long as you have a fuse appropriate for your load and cable size, with sufficient interrupt rating - ANL fuses are perfectly fine for this case).

 

[Sback]

I guess it just depends on how and where you mount your bms. This is a 24v battery I put together.

 

[raurre]

Not the same exact equipment that you mentioned but same problem. This is how I solved it.