Yep a Delta value (the little triangle icon) of 0.014v is perfectly acceptable! Great job!
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Any thoughts about nickel strips from nkon, guys?
There was a bad batch once upon a time, but everything I have heard recently has been fine.
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Sounds great, thanks
Hey quick question, If you bypass the discharge wire on the bms and just put the wire to the source like so:
Does the battery regen charge work? Or does it no longer work that way since the power isn’t going back to the bms? I would like to know that so I can put that on 0 amps since its not necessary.
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Regen comes from the ESC, so yeah it works fine if the BMS is bypassed
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You still have battery regen. And fwiw even if you discharge through the BMS it is not balancing the cells when charging back from braking, so nothing would be changing there.
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Thanks. I just checked what happens if you put it at 0. You have no brakes lol
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Hello everyone, I’m hoping to get some opinions on cells, specifically the insulation at the top.
Background:
I’m building a 4s7p pack to use in a power bank for my Onewheel/eskates. I had intended on using Samsung 50e cells, but then 18650BatteryStore had a sale on their rewrapped 50g cells (they were $5 a piece) so I ordered those.
Having them in front of me, the positive terminal is sunken lower than I’ve seen on most cells. It looks like there’s an insulation ring on the positive, under the wrap. And the wrap itself is noticeably thicker than the wraps of the other 21700 cells I have laying around. I have a few, mostly P42a’s and a couple of 40T’s that I use in flashlights.
It looks like these cells were rewrapped and insulated for use in vapes, which would make sense with how those cells are treated in the machines.
My question is, given how sunken the positive terminal is (about 1mm below the wrap surface) and the rigidity of the surrounding wrap, do I still need to add fishpaper rings at the positive?
It doesn’t look like it needs it with this rewrapping job, and I’m unsure if the further sinking down would have an effect on the welds to the nickel strip when I start assembling.
These aren’t going in a board, they’re going in an enclosure to use as a portable charge bank. So they won’t be subject to particularly high stress.
I’ll include pictures.
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Paging @Skyart
I’m building a double stack 21700 in the flux enclosure, (more like tessellated so it fits) similar to yours:
I think a roll of 50mm wide nickel would properly fit the cells and fold over with ample room for series connections. The enclosure is like 40mm deep so I think I would have enough to bend over, maybe 15mm or so to solder on. It wouldn’t be touching the bottom of the enclosure as there is a few mm of cell it isn’t touching; as you can see in @ZachTetra’s orientation
What do you think?
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If you don’t mind, where do you source that sizing of nickel?
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Many thanks!
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tight pattern!
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Not mine!
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nonetheless
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54.75V full charge, so yeah, a 54.6v 13s LiIon charger will work nicely.
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