I’m not smart enough to know how to hit this.
The set up is a unity and flipksky 6384 190kv motors.
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Yeah. That is how I roll on most set ups.
Much prefer torque over top speed.
lol neither am I. I just understand that there is essentially the green line below is efficiency
I figure youd want to hit it right in that peak there for your sort of flat groung cruising torque needs
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Where is prof. shart when you need him
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Hey dude. Huge thanks for all the photos you put up there.
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Hey dude. The end tabs you have sticking out. How did you finish those?
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Happy to help 
Not sure how he did his, but on my eMTB batteries I solder a full length of stripped wire or braid along the length of the nickel before I spot weld it to the p-group, then fold it over once the p-group is done.
Like so:
If you already welded the nickel onto your first and last p-groups, then probably dont solder down the whole length, as you are going to want to limit the heat transfer to your cells.
Just do pools of solder evenly spaced like so:
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Hi Mooch, thanks for sharing your knowledge.
I’m curious to know if it’s worth it to try to match the cells based on IR, i remember that was a huge bump in performance on a ni/cd batteries, so is interesting to do all this process with lithium ion? I’m about to build a pack of p42a, 18s2p
Appreciate your input man.
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You could possibly get a bit better performance (run time) by matching based on capacity and DC IR but only if you can accurately measure both. There’s no way to give you numbers on how much better though as it depends on the size of the pack, which cells, their condition, etc.
Actually, you don’t need accuracy as much as you need consistency. You don’t care what the actual capacity and IR are. You just need to be able to directly compare the readings from each of the cells.
Recently manufactured cells from a major manufacturer, all from the same batch, might not need matching at all as they’ll already be reasonably close if purchased together from the same vendor.
Using a very good charge BMS will take care of some of the safety stuff but performance will always be based on the lowest capacity/weakest cells.
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Perfect.
Thanks dude.
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Wanted to ask a noob question:
I see more and more people using fiberglass tape in their battery builds. But why?
Some people are using it to hold p-groups together, but isn’t silicon good enough? Why add another layer of insulation?
Some people are using it to cover everything up when finished instead of shrink-wrap – is that considered safe?
Finally, I see some people using it on top of kapton tape to make the heat-resistant insulation layer more durable. Do people agree with that sentiment?
Truth be told, I spotted some in my local hardware store and bought it, but now I’m trying to figure out where I’d even use it for an ordinary battery build 
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I use it to add more mechanical structure on top of the hot glue I use to hold the cells together.(hot glue is not that great)
Also it is cheap…
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Hope this helps
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12 x 7.5 cells, assuming each cell + the insulation is 22mm thick and with welds 75mm high, you need a length of AT LEAST 12 x 22 = 264mm, and the perimeter is 2 x (75 + 7.5x22) = 480mm, so you need AT LEAST 250mm in flat width. (I’d recommend 290mm)
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300mm is what I use for that size and similar sized packs
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Dude. How do you do the balance leads on these?
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on the side on a strip of fishpaper?
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Depends on where the pressure is going to be coming from when you have it mounted up in your case.
If you have dead space above it, then I would run the balance leads on a strip of fish paper on the top, and drop leads down the sides in the valley between p-groups.
Like so:
Im not suuuper happy with where I soldered those on, as its always best to solder in between two cells (as far away from the contacts of the cell cans as possible) assuming that you are using wide nickel. More like this:
(Top side)
(Under side)
It also depends on where your BMS is going to be. Probably best to figure that out first, then run your balance leads accordingly. Brick packs are very forgiving when it comes to running balance leads.
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