As above:
Not sure about that, here is a few weeks old picture I took which shows otherwise, self discharge rate:
Thoughts?
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what are the issues with a pack in this formation with the long cell groups? is this fine even if the .2 nickel is doubled up + copper added?
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This is not the way to do your series connections with that pack orientation. The welds will break without a doubt and this battery will have limited longevity. Youāre also soldering basically right onto the can which will damage the cells even if youāre quick about it. Liion does not like heat.
Thereās much better pack designs than this. What is the reason youāre considering this method?
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not me, from this video - 72v 54.7ah mega range diy battery build part 1 - YouTube
I know its bad but was just wondering if its feasible.
My anxiety and questions increased as i watched the video. At 26:45 he says thereās no bms
Also did a single weld for the thin nickel strip that is used for a series connection
Ya nah, that method is gonna cause all sorts of shite.
What are your needs? Double stack w height restrictions? Triple stack? 
Is my BMS still safe to use?
I was fucking around with my board, had everything loosely in place with some bungee cords wrapped around my deck to hold it all off the floor.
Heard a massive pop, saw a big blue spark. Panicked and unplugged everything and upon immediate inspection, the only sign of damage is this:
I reckon either the metallic ends of the bungee cords, or the loose phase wires from one unconnected motor made contact.
Battery appears to be healthy still:
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Many houses, businesses, and apartments have had serious fires caused by people reviving dead lithium batteries, is the short answer.
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Unfortunately thereās no way any of us can even begin to guess at what the risk of using that BMS is. If you are going to use it then youāre going to have to be paying attention every second to whatās going on (temperature, voltage, current, etc.) until youāve done enough tests to either confirm itās failed or that it survived without (other) damage.
Do all this in a place where a wildly flaming pack canāt cause any problems, which usually means outside away from kids and pets. Wear gloves, glasses, and enough clothing to protect you.
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I think the best thing would be to buy a new one in that case. While Iām at it thereās a few solder joints Iād like to relocate to reduce strain on the main power output, stop some wires crossing over, and i need to re wrap the pack because I accidentally cut a corner of it
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Better safe than sorry, $20 and an hour now might save your whole house
potenial future broken welds aside, is soldering the copper like that a good way to fuse the copper to the nickel/enough to carry all the current? Say you were super quick with the soldering + pre tinned everything beforehand, would this method be decent?
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Iāve done it before, and it seems to work
Edit: was only 8 cells long on a brick pack
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Itās def not ideal. Batteries flex and move even if you try to make them stiff so adding a ridgid bar as a series connection anchored solely to the nickel is just asking for failure imo.
Iām sure it will work and will be sufficient to carry the current but if you absolutely must do it in this fashion, Iād use tinned braided copper as opposed to a copper bar.
Even still, it will be prone to failure. If you absolutely have to build in east-west orientation, this is a MUCH better method (i.e. folding the nickel over the top of your p-groups). If height restrictions are a problem, use tinned, braided copper or multiple smaller awg silicone wires. Thereās never a good reason to solder on top of cells and you should be adding as much flex to your battery as you can. Even if you absolutely cannot fit braided copper on top (unlikely) you can still set your series connections up the same way and then fold them the opposite way so that they sit beside your battery instead of on top.
Peruse this thread and youāll find examples of this. @glyphiks has posted pics of this exact design. Iāll see if I can find the pics he posted to demonstrate what I meanā¦
Edit:
Here ya go:
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I was having a look at the eboosted enclosure tonight trying to figure out a few things. This is my first battery so Im going to ask a few silly questions probablyā¦ lets jump right in shall we?
The plan
The pack
am I right in thinking the CAD layout will work better for running balance wires etc?
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So Iām seeing an 18s4p battery here. I have a few questions.
First, youāre not done setting up those p-groups yet, correct? I donāt see any fish paper aside from the pos terminal rings.
Second, assuming this is a double stacked enclosure, why then would you put the bms on top of what is already the tallest part of your battery? Imo, thatās also going to make running your balance leads a bigger pain.
I donāt think Iām fully understanding the plan for your pack. Maybe you could elucidate a but more about your overall plans for the build- where other components are going etcā¦ for a frame of reference?
If you want to use cad to plan the balance leads Iām sure that would work but I would be in favour of a wiring diagram. You can use a program to do that but Iāve also hand drawn them.
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Id just replace it. I had an esc blow up next to my bms and im replacing it despite it probably being ok. Its not a risk anyone should take with liion cells
Getting ready to solder. Itās my first pack and Iām having trouble finding any info on how people run the wire for an 18s. Here are the two examples I could think of, are either of them more safe than the other? Am I missing an easier method? Thanks!
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This is a @Skyart battery. You can see he runs the main neg terminal up the battery under the balance leads (black dotted line added to illustrate the non-visible wire):
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