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Tesla 2170 for esk8

oh sorry, are you ok?

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And please pretty please don’t try to epoxy your suspension on…

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12s5p being built :stuck_out_tongue:

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I’m gonna start a new thread for the tesla 4680… now I think

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I wonder if tesla is also doing researchs on solid state batteries​:thinking::thinking:

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Elon says they watch any and all battery tech, so if it is promising then they are.

They have said in the past if you have something good that you should bring it to them.

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I’ll be building a 14S10P pack for an eFoil soon. I expect to pull about 30-35A continuous from the pack, so not very much per cell. Peak around 100A, 120A at the most. What do you guys think, is there more discharge Wh available from these vs P42A at those consumption rates? Even if these lose slightly against P42A, I’ll still probably get these because of the attractive pricing…

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Thats the million dollar question that we are waiting for @Battery_Mooch to answer with his test results.

You and me both, buddy

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I bought mine from techdirectclub.com, who still has them in stock. A tad cheaper than Batteryhookup, free shipping :slight_smile: $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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@Battery_Mooch any word on your test for these?

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.