Always good info! Is there a recommended way to measure IR of the cells or p groups? We have access to a D6 pro and I want to rule out human error.
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If the D6 Pro has a that feature then definitely use it. 
It would measure the resistance of the cell but also all the wiring and connections too. It’s important to reduce that extra resistance and to have a very, very good connection to the cell.
If the D6 Pro doesn’t measure IR then you either need a dedicated IR meter or a charger that has that feature. But I have never seen a round cell charger that has anything but terrible accuracy. Perhaps the LiPo chargers do better.
I use the ESR Meter from ProgressiveRC but it’s an expensive device.
Measure the IR of a known good cell before testing any others of the same model number. This will give you a baseline to compare to. Otherwise you don’t know if a high reading is due to inaccuracy, wiring/connection resistances, or is just from the cell.
Always measure at about the same cell temp and state-of-charge. I typically measure fully charged cells that have sat for one hour after charging is done so they can come back to room temp. Warm cells have a lower IR.
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Actually while on the topic, I know the answer is probably “depends on your risk tolerance” but what do you think about these?
Most that I got are alike or better than the right. The left is the worst one I have. I am going to do some discharge tests on all of them, but is there anything that you’d say is a 100% no go in terms of dinks like this?
I mean they’re dented a little bit, personally I’d feel fine using them for myself
Too bad fogstar wasn’t US lol
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Umm…yup. 
There’s no way for anyone to know what’s going on inside any cell with damage, which is why no damage is acceptable to the manufacturers. We just can’t say when it becomes a safety issue…too many variables and unknowns.
It’s up to each of us to decide what looks okay and what looks too risky to use.
100% No-Go for me would be smoke and/or fire. 
About the degree of damage for that left cell is where I would start feeling uncomfortable. But that should never be used as any metric for your decision. I can’t know anything about the internal condition of any dented cells I have and any decision I make is merely a wild guess. It can’t be any more reliable than that.
The cell on the right I would use as long as I knew it wasn’t banged around a lot, just dented from testing.
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Any further details you can share on this?
Any further info on the problem?
Anything people of the forum can do to check this won’t affect their packs?
Any details on what software changes are being made?
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Are you rewrapping or double wrapping your cells?
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Rewrapping. They’re salvaged from BCH. Some of the wraps were torn and didnt want two colors. OCD much lol
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Does anyone know a compact 20s BMS that does balancing?
I only find gigantic discharge bms or small bms that don’t balance.
I only need like 20-30A discharge
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This but I’m looking for charge only for a onewheel
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Yes mine is also for a OneWheel. Ideally i would like to use the switch of the bms for the OW. An additional 20s Anti spark probably wouldn’t fit.
I’m probably going to use this one but it’s a very tight fit.
Also. I have 27 of the 4p 18650 tabs from @BenjaminF left over. They need a good home. Take care of shipping and their yours.
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is there a clear winner best practice type thing when it comes to connecting the balance leads to a brick pack?
I am leaning towards an ugly bastardized version of what Skyart did here.
soldering the leads to the nickel between the phases.
what is up with doing separate little tabs?
do those just get welded to the main nickel?
I like how kind of out of the way they are.
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What enclosure are you using? Pictures?
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junction box.
room on top for the smart BMS.
where I plan on putting it.
room on the sides …
no room on the ends…
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Could go side and use the tab method.
Are you using precut nickle? If not, cut your parallel strips a tad longer to fold over to the side for balance wires.
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