Questions for my first build: Fusing, loop-key and vesc configs

[b264]

@edoardo

This way with that kind of fuse?

What I’m saying is that I would put the fuse on the charge port itself, not somewhere else in the circuit like that.

[b264]

BMS bypassed with loopkey and discharging with lights/accessories circuit

If your BMS doesn’t have C- or CH-, then connect that wire to P-

beautiful diagrams

[edoardo]

@b264

Well, there have been long discussions on this topic, and both ways have pros and cons.

But me personally, I value my body more than my battery or ESC, so I feel this is safest for body. If something terrible is happening, I at least want to have a chance to hit the brakes before the battery goes nuclear, without a fuse popping and killing any chance I have to save myself.

If built and operated correctly, your current should not be going to levels above that anyway.

That’s the short version.

Yup, I read some topics about it and I remember this opinion. Ok thanks.

@b264

BMS bypassed with loopkey and discharging with lights/accessories circuit

In my case, something like that:

@b264

beautiful diagrams

I say nothing

I bought these, they are ok?

[b264]

@edoardo

In my case, something like that:

Looks fine to me

[edoardo]

Good! Please can you also confirm the fuses that I linked?

[b264]

I didn’t see any links, but these work good for charge ports

https://www.mouser.com/ProductDetail/Littelfuse/0997007.5WXN?qs=sGAEpiMZZMsh2y49K8ANrYB63nQN2nH5H23b06A9xQM%3D

for 5A max charging. I epoxy them inside the enclosure somewhere near the charge port and just solder wires to them. If you ever blow it, just epoxy a new one on top of it. Typically they don’t blow, and if they do, then you’ll have fun changing the fuse knowing that you’re not buying a new battery or house.

[edoardo]

@b264

I didn’t see any links, but these work good for charge ports

https://www.mouser.com/ProductDetail/Littelfuse/0997007.5WXN?qs=sGAEpiMZZMsh2y49K8ANrYB63nQN2nH5H23b06A9xQM%3D

for 5A max charging. I epoxy them inside the enclosure somewhere near the charge port and just solder wires to them. If you ever blow it, just epoxy a new one on top of it. Typically they don’t blow, and if they do, then you’ll have fun changing the fuse knowing that you’re not buying a new battery or house.

Great! Thank you. I actually think I’m going to use the fuse holder ( I really like a clean hw setup ).

@b264

I recommend no fuse on the discharge line

What about using a fuse to avoid only a short circuit identifying the device with the lowest amps limit?

For example my VESC can handle 150A (instant peak), so using a 120A fuse might be somehow useful for the electronics? Considering that I don’t expect to set “motor max current” higher than 85-100A.

[edoardo]

@b264 Sorry for the quote, can you check my last post?

[b264]

Sure.

@b264

I recommend no fuse on the discharge line

Cheers

[edoardo]

BTW I solved by designing and printing an holder .

Here is it:

[Venom121212]

Very clean!

[edoardo]

Thanks!

I shared the design if it could be useful: https://www.thingiverse.com/thing:4776368

[skatebored]

Why is the fuse on the negative?

[Fosterqc]

Because we are currently in the shadow realm

YOU NEED TO WAKE UP

[b264]

Because the nature of MOSFETs means a common anode design is cheaper and more powerful, so that’s why BMSs are designed to switch the negative lines.

[skatebored]

No, an added fuse on charge line, is shown as on the neg.

[b264]

It doesn’t matter which side it’s on.