I bought mine from techdirectclub.com, who still has them in stock. A tad cheaper than Batteryhookup, free shipping 
$60/25 cells. I built a 10S6P pack for my mountainboard, just placed an order for another 50 for a 10S5P flat pack for a DIYE enclosure. (Max I can fit in a single layer… no room for ESC, just barely room for a thin charge-only BMS on top.)
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Could you explain your pack construction method here? I have never seen anything like that, it looks very interesting!
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I’ve wondered if this is false economy vs 40Q / Molicel 42A as well. I’ve been riding my 10S6P pack since Labor day, just got Metr working again so I can see logs. With Flipsky 6374 motors, FSESC 6.6 set to 65A max motor current, 99A max pack current, log from Sunday shows (I’ll post it in a sec) 103.4A max motor current (total), 29.2A average (total), -46.6A min (total max braking), 44.9A max pack current, 15.1A avg, -19.3A min pack current.
Here’s the log: https://metr.at/r/scY1O
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Batteryblocs. It’s a compression pack with a Neodymium magnet on either end of each cell, stuck to a galvanized steel plate. Compression is provided by the nylon screws holding the sandwich together. Stupidly easy to build, but the maker has not done any real high-current testing. I question whether my board is hobbled by this thing not being able to deliver more than the ~50A peak I see in my logs. The sheet metal is roughly 1mm thick, and the strips are about 2in wide (minus the 5/16dia holes) but steel is an awful conductor. For a topside bag, I’d gladly build another, but adds too much fat for an under-deck pack.
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Just from glancing over this:
- looks like you discharged 423Wh from ~39V to about ~33V.
- there are some not-so-suble voltage drops when you pull a lot of amps.
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Im now wondering if this contributed to the voltage sag under load that I saw in your metr log.
Remember that I’m coming from the world of tired Evolve Lipos… The worst sag I can find in the log is when I was already running out of juice, hovering around 32V, dipping to 29V under heavy load. With more of a charge in the can (I started the ride around 67% / 39V) seems the voltage sags maybe 0.5V under heavy acceleration. Are there really packs that don’t sag at all with a 50A draw? If this is the sort of performance I get with $2.40 cells, I’m in little hurry to use $5 cells.
The 50 cells on the way will also be built into a compression pack, but using 2x layers of 3/8in copper braid, roughly equivalent to 9ga copper wire, instead of magnets + galvanized steel plates. I’m also using smaller (6354) motors on that build. If I get better torque from that setup (apples-apples… 9in/72t/12t vs 8in/66t/12t should be almost equal final ratio) and less sag, I’ll look at upgrading (adding a copper layer) to the plates on the Batteryblocs pack.
One more X-factor for that log. The 10S6P 2170 pack is in parallel with a 10S1P 2.2Ah Lipo pack with a lower nominal voltage and nothing to contribute under ~3.5V/cell / 35V pack voltage. I should remove it. The idea was to bolster current capacity (it can provide 135A continuous vs only 90A for the main pack) but as the pack falls under 35V, it’s probably draining the main pack to recharge itself. I’ve got diodes sitting here to properly integrate it, but I don’t think it brings anything to the party if I’m never going to see north of 50A pack drain.
Been battling a flare up of some long term health issues. I need to do a teardown video first to check for internal protection and hope to post the test results soon.
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Yeah they probably would not like you doing a battery teardown in a hospital room
you know, cause of covid and stuff.
(just a joke I’m assuming you are not actually at the hospital)
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Model Y charger
also we need this light guide system for esk8 building
something more achievable could be making it work for the @DRI battery kits.
Hey man, I hope you are doing well 
Any updates you can share with up about the tests for these cells?
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They are next in the queue and should be soon.
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Mine are waiting very patiently to give a good time.
12S8P will be fine I’m sure but will be good to know if it will handle 200A alright.
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That would be 25A / cell. I thought this was a 15A cell. I hope you’re right about 25A a cell.
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eh it will never draw that cont, but maybe more like 60-70A per motor is better
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I’d recommend P42A for that. At 25A per cell (burst or continuous) you’ll be getting a lot of voltage sag with the Tesla cell. You’ll probably get more riding time with the P42A since they will be running much more efficiently and hold their voltage up for longer.
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