First battery build and I’m stuck at the point of connecting the p groups. Is there a certain order? I just don’t want to make a boom.
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That’s how Id do it
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thx bruh…
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I don’t remember which end has both terminals of the cell. Measure the voltage between the center of the contact and the outside “shoulder” on the end of the cell. If there is a voltage difference then that is an end you need to protect.
Or just protect both ends.
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I know this isn’t an option for everyone but I run a 30ft line outside with a 400cfm fan attached, these days just purge everything outside and my hepa/carbon room filter does indoor dust only. I don’t like the idea of trying to filter solder and welding fumes; it being hard on the filter and I’m not certain it gets all the bad stuff. Dump that shit outside imo.
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I have the luxury of soldering in a room with very little ventilation. I have to open my door and crack the window a tiny bit.
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You should make a window baffle adapter to like a 4" dryer line and get a 4" inline fan. It really is not good to do it that way
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My window opens about an inch to prevent people from jumping out as I live in a high-rise building. I do have a fan pointed straight at my face to keep everything away from me as best as possible.
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Yeah what about something like this? Trust me a good venting setup is worth it. Just careful not to backvent other stuff like plumbing and gas appliances. 
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@glyphiks @moddedlife So I found the issue, I sized up all the wiring and connectors and made everything as short as possible. I’m getting solid pure nickel welds at 26MS now.
Cant believe it was this simple… I think I’ll upgrade my tips too.
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Yeeewwww! Excellent news 
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If it was a professionally made pack then this is ott as it is.
You need to think about how you use materials and why.
Li ion shrink rap is good as a insulator but easily damaged by friction. We use fish paper as it’s good agains abrasion
Is part A going to potenchal rub and vibrate agains part B and do these parts have voltage potenchal?
2 cells with in a p group the out side is - and there is no potenchal difrence no issue if that touch
P group 2 may rub agains P group 3 yes voltage potenchal add fish paper were thay meet.
You have raped both p groups so you have added redundancy as there will now be 2 layers between the p groups. This is not needed but also doesn’t hurt (apart from useing more space, materials, time)
When you add fish paper you use space up and now the cells can’t get as close as thay could befor. This means where the fish paper is a little short there is now a permeant air gap so thay can’t rub agains another p group. As @glyphiks said put it as close to the positive end as possible this is because of the nickle that you may be wrapping around later
And this is why a lot of non battry builders think well made pre built are over priced. Lots of ways to save time by taking short cuts to offer a cheaper battry . why we see so many opened packs in with bad workman ship as once it’s shrink raped no one really checks.
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@Battery_Mooch Do you know who set the nominal voltages for different cell types? Is there some sort of international battery cartel?
Why do Lipos get 90% of their capacity above the nominal voltage (3.7) while Li-ions get 50% above the nominal 3.6v? Surely it completely throws the Watt hours comparisons out of the window.
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Each manufacturer sets the nominal voltage for their cells but the chemistry of the cell sets a narrow range of values.
Any cell’s nominal voltage or nominal capacity spec is useless for calculating and comparing Wh specs unless you are using the cell at verrrrry low current levels. That is how the nominal specs are set.
At the discharge current levels we use cells at the Wh numbers are much lower and can vary considerably depending on how hard the cells are used. Two cells can have equal nominal values but have completely different specs for the Wh delivered at higher current levels. This is due to the cell’s chemistry and internal resistance.
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My first brick battery. I have .15 x 25mm pure nickel. Do ya think it will be ok for 80 amps max. 10s8p …3500mah 10a lg mj1 cells. Series rails will be soldered 8 ga copper
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