What added resistance?
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“technically” the contact area inside an XT90s is smaller than a normal XT90, since part of it is taken up by the resistor loop
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Try and avoid it. I’ve done the same as Jake and connected at various differing voltages and monitored with a clamp meter. I was pretty surprised at what you can get away with.
As long as they’re close it’s typically fine.
My setup was also exactly how Jake drew the schematic.
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my 18s pack had what looked to be a bad cell so group 4 was lagging behind.
I replaced it with new cells, and now a month later of the board sitting in storage, i checked the bms app and was surprised to find my pack 1 doing the same shit.
I messaged the battery supplier in hopes to get some new cells in case i need to replace and am just getting huge paragraphs of confusing info.
My welds are great, this group never showed any issue before…im a bit lost on what to do. no accessories that could be draining power. just plugged into the ESC.
Im currently static balancing atm so to avoid opening the enclosure, but its been a few days and group 1 continues to drain??
I have no idea what the programming is like on these controllers but i know they accept 400battery and 400-800 phase amps. sounds like the long-range pack would be more than fine with the 0.2mm but i’d like to be able to make a molicel equivalent to use with these high-powered controllers. I guess just get 0.3mm?
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The bms b- to main negative was to thin of a wire guage, my problem has been resolved. Thankfully
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The BMS draws some amount of power, I’ve found static balancing has to chase the lowest cell downward. …
as to why the replaced pgroup is again out of whack, suggests something else is amiss. i can’t guess what.
I’m not saying this is the issue, because it really shouldn’t be. Any designer worth a damn wouldn’t let it be this.
With that out of the way, it’s possible that your BMS is drawing power from group 1 to power the BMS, rather than drawing power from the whole pack like a sane person designed it. It’s easier to use a 3-4v supply to run a microcontroller than to use 50+ volts after all…
I’ve heard that some Makita batteries were designed that way and had a tendency to kill cell 1 as a result.
Now I’m not saying your specific BMS is doing that… but it is possible.
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Its constantly draining, first was 3.73, then 3.65, now its at 3.63. Its an LLT bms . also i havent gave it a charge at all in about a month,
The replaced pack is fine, this first group is now having the same issue as before.
Are there any config settings I should modify? Never had this happen on any of my packs
Hit that heat shrink wrap with more heat and for longer. Most wrinkles will “iron” themselves out with enough heat and time but just be careful not to get the heat source too close or else it can burn a hole in the wrap.
I have no help for the battery but saw the shrink wrap and it bothered me so I had to mention it. Plus I know I’ve done the same thing before realizing it just needed more time before it would fix itself. Sometimes a wrinkle gets stuck which annoying AF but usually it is small enough to not cause issues when putting it into an enclosure.
Agreed. Plus why top mount when risers exist and are cheap to buy? just make the build taller and have more fun 
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Here…
Also its literally vynl. Not shrink wrap, my sister works at a shop and sends me scraps so i have infinite.
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I’m going to pretend not to be bothered be the vein appearance because I’d probably do the same thing if I had access to free materials
I only mentioned it since where I bought my large heat shrink wrap from didn’t tell you that it would eventually flatten itself out with time and heat and I think I wasted enough for one battery wrap if not more before figuring it out 
That stuff isn’t cheap either and I already wasted money buying a size that was like a mm too small back when I had no money so I was not happy about the unneeded waste
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Ive had no problems with vynl, its cheap but needs extra care when applying and removing but again its because i have so much random pieces. I hate wasting reasources as well i opened each pack a few times and went through like 20$ of heat shrink for wires in one sitting lol. Id use the better stuff if it was avaliable at local stores,
Is it? I mean the battery wrap.
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You’ll probably want to order heat shrink online. You want 4:1 adhesive-lined stuff. I rarely ever see 4:1 in shops, best I usually see is 3:1 and most HW stores only carry 2:1
And forget about the PVC wrap. Get yourself a roll of wide kapton tape and some strapping tape, that should be all you need besides fishpaper and glue.
I bought mine through amazon. Ended up having to size up more than I had originally expected, but the stuff I got shrinks down a ton. The original wrap I bought for a standard 10s4p battery shrunk enough to fit my hairdryer and hold the nozzle in place and was almost large enough to fit the battery. (I lost the OG piece and you can’t buy that piece on its own)
Ignore the epoxy on my hairdryer. it is cured on there because I never cared enough to clean it before it cured, but as you can see it is much smaller than even a 10s4p battery would be.
You’ll have as much trouble welding that as you would the copper afaik but do some research on here and maybe endless. Not sure what else to point you towards if you’re adament you need to carry 400 amps continuous… you might just be better off with the copper if its a choice between that and 0.3mm nickel tbh. You’ll have to make the call.
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Isn’t it 100J for 0.3mm on the kweld?
Would double stacking 0.15mm be the better option?
ah, i guess, good it’s a different pgroup… but. hmm. are you verifying with a multimeter that match the readings the smartbms is giving you?
did the replaced pgroup give any clues? did you capacity test the removed cells afterwards and see if they were degraded?
when that LTT smart bms killed my battery after letting it sit too long it did it nice and even to all the pgroups.