I use the same one with my kweld, also a single. Works fine, shit just gets very hot pretty fast. But for casuals totally ok. If you’re not a casual you should use something else anyway, like a car battery on trickle charge f.e. .
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Hey what does this mean, should I Chuck these cells cuz a the rust at the bottom is the electrolytes leaking out? I’m prob gonna use em anyway, I’m building a bomb I mean board for an enemy I mean friend of mine.
Edit: the percimon are just for reference
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If you aren’t concerned about your friend’s safety, and are going to use these cells, I’m confused why you’re asking us if you shouldn’t use them. 
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Where can I buy/ask for dead cells to test my spot welding on? Anyone in Chicago here have some cells to share?
These are $0.40/cell but won’t require any cleaning like salvaged cells
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Do you or any other big brains have info on how this compares between different chemistries? I’ve had to take a second look at some LiFePO4s in the last few days because I got blind sided by the amount of current one of those 123A cells can put out, that combined with LFP’s cold resistance makes me curious if there’s a noticeable difference with them or LCO
Smooth brain here, but LiFePO4s can put out some serious amps, experience little sag, last a really long time and are relatively safe. Downside is lower voltage and less energy density.
This small pack will happily melt a wrench
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$25 shipping on a $4 purchase 
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Sorry 
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As @jaykup mentioned, some LFP cells have very high current ratings and they all have a nice flat discharge curve (hold their voltage steady until almost empty) if not stressed too hard. Cycle life can be greater than the LCO, NMC, and NCA chemistries used in “standard” li-ion round and pouch cells but is not guaranteed.
The energy density of LFP cells is verrrry low though. 18650 LFP cells are around 1100mAh. LFP cells run at a lower voltage too so the power density is also very low. This all adds up to a very heavy pack for LFP if you want to match the energy and power of a NMC or NCA pack.
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LOL…I didn’t answer your IR vs temp question…
I don’t know how a typical LFP cell compares in this regard to LCO, NMC, or NCA cells.
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First experience with a brick pack and high voltage. Went well, but came out a bit ugly. I gotta work on my fiber tape skills 
I gotta say, this is the first pack i was able to knock out in a day (I dont have a bms yet, but that wont take too long). I put abt 6 hours into this at my sluggish speeds too and most of the work is done 
I just gotta figure out what dia heatshrink I need
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Here are my very first spot welds! So appreciative of this thread for all the domain knowledge to get me started. This was done with the kweld:
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Big mood 
🫂
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The welds look a bit hot…
The negatives look a bit concerning. Did you check that you didn’t blow through the nickel or pierce the can?
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Yeah, that was the only one that sparked when I spot welded.
How would I check to see if I pierced the can?
awesome feeling, this is. I wish you luck with your build and great success!
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Well, if there’s a hole into darkness, that’s a bad sign. Or if there’s a leak of liquid that smells particularly different and a bit metallic.
You would have smelled it. Sickly sweet chemical smell.
I agree with Mario, those welds look damn hot
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Sniff all your negative welds
SNIFF THEM!
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