Or geez look up resistance for copper and brass, something like
https://www.radio-electronics.com/info/formulae/resistance/resistivity-table.php
and take a ratio?
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to each with his own method 
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or just take a look at a chart theres a chart for everything related to engineering
Wooh sry for charing . the fuck 
I’m all for cell level fusing, but it doesn’t mix well with any kind of BMS, even if it’s charge only.
If a fuse blows, then the others in that P group take extra load and likely blow as well during riding.
And if any series connection breaks within the pack while you’re riding, suddenly your VESC turns off and you’re now feeding your full pack voltage through the balance wires surrounding the series connection instead of the expected 4.2V max difference. This situation would very likely burn up your BMS and i’d even go as far to say it’s an unnecessary risk of fire.
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Why is that ? Sorry, did not read the whole message.
Regarding the first point, if you design your fuse to blow with the continuous discharge rate of the remaining cells, then it’s true. But if you assume that a shorted cell can deliver much more current in a short that its max continous discharge, you could design the fuse to be large enough not to blow with the remaining cells, couln’t you ?
You could, but then you have the issue of uneven discharge because you wouldn’t necessarily know that you blew a fuse, it’s inside your enclosure. For a 2P pack that means you’ll deplete the p group twice as fast as the rest, and after that… cell’s dunzo. A BMS can’t correct for that kinda difference in capacity.
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That has been my interrogation with cell fusing. How do you know that you’ve blown a cell ?
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If you have the diebiebms you could check via metr.
Maybe an alart could be set up as well.
You cant technically distinguish missing cell in P group. The only thing that can change it will discharge faster as capacity is lower which would make P group voltage lover than others but balancing can hide it…
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This is exactly what concerns me with cell level fusing.
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But whats the problem ? If you have a BMS, it will stop when the group reach the low limit voltage, won’t it ? The fact that there is a missing battery in the p group will not disable this feature.
@Lumaci : How would the DisBieMS notice the missing cell ?
For one thats super worriee about p groups dying or cells or whatever I would reccomend them to get the bluetooth bms, you can see each p group voltage and turn on balancing or turn it off and edit so many settings it will get really confusing
Having a dead cell in p group does not change it’s voltage, does it ? How would you tell something from the voltage only ?
It changes, but not right away, the voltage will drop faster in this group, and also the sag will be bigger
I didn’t get the problem with the BMS and cell level fusing, or are we talking about the main fuse blowing and all current count through the balance wires? If that’s the concern just add fuses to each balance leads, there are some smd fuses that are really small
Should inuse 2 12 guage wires or 1/2" tinned copper flat braid for the series connections?
I chose to use 2 12 gauge wires as I don’t have any braided copper wire. I read someone say that the braided copper wire also wicks a lot of solder making it rigid. I don’t know what the amp ratings are for the braided copper wire but when choosing a solution for my batteries I wanted to try to reduce the amp draw over the nickle strip so I put 2 pieces of 12 gauge wire between the cells so fewer amps were being pulled across the entire nickle strip.
No it would be better if the main fuse blew. But if all the cell fuses blow in one P group then the balance wires surrounding that breakage will be exposed to full pack voltage instead of 4.2V. the current is irrelevant (but inevitably more) and the extra voltage is what will do the damage. The components on the balance board portion of a BMS are not rated for something like 42V. And last I checked, there’s no such thing as a fuse for voltage 
There would be 0 voltage. The battery would be splitted in two separete pieces.
So rather burn the whole board, and not the BMS?
Actually, if a load is connected to the battery (like a vesc) then the two P-groups that have been separated effectively become the new + and - terminals of the entire pack. So the voltage will not drop to 0, it would drastically increase. A vesc always uses power even when idle and is therefore a load.