I would think he wants locals to take some. I would be interested in practicing my teardown skills
if u get those a123 cells from me I’ll cut the cost. Cheaper than if u get them yourself and have to disassemble them from the packs.
I’ve torn them all down already. They show 97.5% capacity.
now thats interesting! i was just gonna grab up 200 p26a and sell off the leftovers. im bothering my investment guy today to hurry tf up putting my money in my bank so i can get to actual purchasing phase, but i could probably swing that this check even if he does take forever xD ill message ya!
unrelated: bro idk what wizard runs my account with fidelity but that shit goes up at least a thousand a month not including my actual contributions.
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Lifepo4 for life!
Batteryhookup has brought me to the light and it’s not a cell in thermal runaway.
Won’t bother charging past 3.4v anymore or even below 3.2v and almost all the energy is within a nice .2v for consistent power and speed.
https://www.powerstream.com/lithium-phosphate-charge-voltage.htm
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This is what makes then totally awesome in aonewheel, but bad the highly valuable range. 24S1P got mer just over 10 miles on and off dirt trails.
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this is crazy cheap now, basically like the cost of the fuse plus other bits…
Please someone want a monster 26lb pack…
Really good for a bike I bet.
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@Battery_Mooch What kind of real numbers could I get from this?
How do these prismatic cells compare in terms of safety, the alternative is me building with NESE modules? Can prismatic cells like these handle vibrations?
It would just fit as a top mounted enclosure on a MTB, or failing that I’m planning a ebike, is this a terrible idea?
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These have metal on the outside which is dope for protection and mounting. Can’t really get easier than these, besides the possibility optional BMS installation and having the get output wires with hopefully a fuse made.
I have no idea. 
You’ll have to check the claimed ratings and search for those who have used them.
Prismatic cells come in many different battery “chemistries”. LiFePO4 (LFP) is the safest but is not “safe”. You still need to respect the power they have.
BH doesn’t say they are LFP so they seem to be standard Li-Ion cells, same chemistry as the round cells we use. Check with BH to be sure though.
Not any better than round cells but it completely depends on how much vibration reaches the cells themselves. A metal frame mount can absorb shock/vibration or just pass it right on through to the cells. You’ll have to dive into how that module is constructed to see what it can/can’t do.
I don’t know if there was additional shock/vibration protection that module was mounted in or if the protection exists as part of that module. I haven’t looked at it for more than a couple of seconds.
Not at all!
The devil is in the details though. The mounting and protection (electrical and physical) you give the pack, like for any pack, is critical.
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Seems prismatic are better with shock/vibration and cylindrical are better laid on their side.
https://journals.sagepub.com/doi/full/10.1177/14613484211008112
Causing internal short circuits. Yikes.
I imagine no bms will save you from a fire if an ion cell internally shorts. Makes me feel even better with lifepo4. Anyone know where u could get A123 cells for a buck? 
I further imagine a skate deck may be one of the harshest environments in this regard.
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For that first paper…
We have to be careful when using research papers, they are typically quite specific in where their conclusions can be applied.
That paper mentions pouch cells. We don’t know if prismatic cells are similar enough to have the same advantages and disadvantages and prismatic cells from different manufacturers, in different hard cases, can have different strengths and weaknesses.
Their warning against the use of mandrel-containing round cells in certain orientations is a good one but there are very few cells with mandrels (the LG HG2 is one). Most are solid internally and are not as susceptible to vibration as the ones with mandrels.
Vibration and shock are to be avoided though, it’s never a good thing as no cell is designed to handle it alone.
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Agreed!
That second paper was great, thanks for the link!
They tested, and warned against, the use of mandrel-containing 18650’s but tests on other 18650’s (some presumably without mandrels) show that vibration/shock can accelerate the aging of a cell and/or damage it badly. No one should be surprised by this but it’s great to see some hard data on it.
Bottom line folks….protect your packs if you care about them lasting!
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I assumed all the cylindrical cells were wound on a mandrel or something. What is a solid cylindrical cell or can u explain the different physical designs?
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I’m guessing that all are wound on a mandrel but many have the roll of stuff pulled off the mandrel as it’s put into the can…maybe all of them.
The only way the bottom spot-weld can be made is if the electrodes can go down the middle of the cell and a mandrel would get in the way of that. I’m guessing that if a mandrel is used that it’s added after the bottom spot welding is done.
All 18650’s have a bit of space at the top and bottom of the roll of stuff so that provides an opportunity for movement if the plastic insulating/padding disks at the top and bottom don’t completely fill the space.
Checking out some x-rays of cells will explain things a lot better than I can with words.
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Just a side note…the mandrels in li-ion round cells are tubes, not solid. They’re used to keep the cell’s stuff from clogging up the central core opening when the cell is in thermal runaway. The tube allows gas to escape from the bottom of the cell instead of, possibly, allowing the pressure to increase enough to burst the cell.
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This is some really good info on the effects of vibrations, it’s got me looking into mandrels and stuff. Here’s a screenshot of a youtube video, and it’s got a source in the bottom right corner that might have more data on which cells have mandrels.
The A123 battery model listed there is not one of the 2 listed for sale on the a123batteries website. I’m not sure if they’re built the same way, but maybe it’s a good idea to lay them horizontally when building packs?
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Unfortunately that source is a purchase-only paper. 
I’m confused by that screen-captured table as every HG2 I’ve seen opened up has had a mandrel. Perhaps they don’t anymore.
This might be good advice for any cell since we might not be sure if they have mandrels (or not).
But only if we can confirm that there is minimal lateral shock/vibration. Or at least, a lot less than what they would experience if positioned vertically.
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