don’t huck it just yet.
manually balance through the balance connector and see if the BMS can keep up with it. If the magic smoke is still inside, and it charges, it’s probably still working.
2 Likes
Hi guys! I’m assembling my first board soon (and consequently my first battery pack soon), and I was hoping I could get some feedback. I’m making a single stack 10S4P battery pack from Samsung 30Qs. Each battery group will be laid next to each other. How does this look? I would love some criticisms/corrections.
Is the wiring correct for a (discharge) bypassed BMS?
Are 4 wires between each serial pack overkill? / Is the serial connection between packs 5 and 6 overkill? (would one or two wires be sufficient?)
Should I have any fuses between the battery pack and connection to the FSESCs? I heard this is a no no, since if the fuse blows, you have no breaks. Plus the FSESC will shut off on its own when there is too much voltage/current.
Do the balance leads belong on the negative side?
It seems like this BMS comes with 11 leads (correct me if I’m wrong). Does the “b-” lead go to the negative end of the first battery group in the pack? There also seems to be a “b+” connection. Where does this go?
I came up with my diagram based on these:
b264’s diagram
The BMS I used
The fuse(s) I used
The charge port I used
I will be charging 42V @2.5A, if that helps/matters to know.
I plan on adding a light circuit in the future. A voltage step down is needed, correct? (Link: https://www.amazon.com/Pololu-Step-Down-Voltage-Regulator-D24V6F5/dp/B016VG8XI2)
If you’ve come this far, thanks for reading!
3 Likes
Looks decent, I would say 4 wires for 10s4p on 30Qs is way overkill, probably 2x 12AWG is plenty
The rest of it checks out. Don’t need to fuse your Vescs at all, the charge port fuse is good tho
That is how you wire for bypassed discharge too, so good on that.
2 Likes
Awesome! Thanks for all your input, you’ve been so incredibly helpful!
2 Likes
I rarely see fused vesc in pictures or diagrams.
But my VESC is fused. it blew a fet horribly. and is currently directly shorting it’s powerleads and blows the fuse.
I get curious how much more smoke would come out if that fuse was not there. or if it would lead to fire.
2 Likes
Hm yeah yours was the worst fet explosion I’ve seen haha crazy that it shorted the power leads. Never seen that before
1 Like
Interesting… I’ll consider placing fuses for each FSESC then, thanks!
Just keep in mind if you manage to spike above the fuse amount you could lose your braking entirely. I don’t think it’s wise personally, and I think fessy got unlucky
@fessyfoo what rating was your fuse
1 Like
I might be wrong about this, but if the fuse were to pop that would be the equivalent to unplugging the ESC during operation. And iirc that guarantees a pop.
3 Likes
That’s why I don’t think it’s a good idea, especially if it’s on CAN, that guarantees both of them dying if it’s 4.20 hw as far as I know
2 Likes
40A fuse on 35A battery configured VESC.
I would pull the balance leads from the negative ends of the cells, except for the B10 / B+ one
1 Like
They don’t “belong” there, electrically it’s the same
The difference is when you have a balance wire wrapped around the end of a cell and it’s under heavy vibration for extended periods of time, if it’s at the same voltage as the cell casing below it, there is a smaller risk of shorts and fires. On 18650 li-ion cells, the cell casing is the negative lead.
On A123 cells for example, you’d want them on positive since the cell casing is positive.
6 Likes
Anyone have any experience with this 10AWG?
https://www.amazon.com/BNTECHGO-Silicone-Flexible-Strands-Stranded/dp/B01ABOPO2S/ref=sr_1_6?dchild=1&keywords=10+awg+sili&qid=1596779282&sr=8-6
I would order from common sense but they r out of the 3 ft combo packs and their 10 ft packs r way expensive
2 Likes
I have bought silicone wire from BNTECHGO multiple times and it has always been good. Cant really see a difference between that and Turnigy.
2 Likes
This is the only kind I’ve bought, great stuff. Super thick and super high strand count
3 Likes
SOLD
2 Likes
Lol I’ve thought about trying the hobbyking stuff but this has just always worked since I started building in 2017, so I never switched
2 Likes
I bet both come from the same part of china.
Also the two kinds I have got lol
2 Likes