Tesla 2170 for esk8


who wants the last 28 from BHU?

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I mean it would mean i could go 12s10p I suppose… nah. lol

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They might have more to list but maybe not on sale anymore.

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Good find, was wondering how they can make it make sense time wise to remove the cells

But holy hell, how can someone make a 360p video in 2020

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Is the discharge rate of the ok for a 12s3p? Or would I be better with the 40t in that format, or even a 4s 30q pack? Price and MAHare tempting, but I’ve got limited space.

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Interestingly the P85D cells (at least) are used pretty hard when in ludicrous mode. 20A discharge! I wonder how much Tesla pulls from these batteries. If its 20A, then the price-performance ratio of these cells is pretty phenomenal. Absolutely perfect cell for a 12S8P MTB build for example.

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@DerelictRobot you get your order? Whatcha think

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I think the important thing to remember here is how excellent Tesla’s cooling/heating solution is. Max discharge rates are best met when the batteries are at their optimal temperature. The system does its best to keep the cells at that temperature, and I imagine that is what helps them get the discharge rate.

We, on the other hand, stuff ours in a hot plastic can and beat the crap out of it lol

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Tesla discharge about the same current from the 2170 cell as with the 18650.
Tesla model 3 performance have a max output power of ~480 horsepower, or 353 kW.
The battery in the long rang and performance are a 96s46p battery, containing 4416 cells.
This means that at full power they pull 353 kW/4416 cells = 79.93W/cell.
At 4v per cell that is 79.93/4 ≈ 20A per cell.

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Well, to add to what you’re saying (not disagreeing, just elaborating) it’s important to clarify here, that most lithium chemistries actually can pump more current at higher temperatures than ambient. There’s always a general assumption that cooler is better with electronics, it’s true for semiconductors, but as we all know, discharging at low temperatures, especially below 0 deg C, even the chemistries that are ok to charge/discharge at those temps, it’s far from optimal.

Unfortunately, as discharge rates rise, and cell temps rise, discharge capability rises, and without active highly controlled cooling to maintain the optimal (often up toward 100deg C) temps, thermal run-away can happen and boom selecta! bad shit starts to happen. On top of it, even though performance can increase, so does cell degradation. It’s all very chemistry dependent though, minor changes in the sauce can make huge swings in the performance caveats.

But yeah, they do have active, highly controlled cooling in Teslas, however considering the longevity of the cells, and all the capacities I’ve seen over the years from salvaged cells even from high mileage vehicles, it’s pretty obvious, they aren’t trying to push them to their limits, they’re being nice and hoping to have as much longevity as possible from them. It makes total sense, one of the HUGE consumer perception hurdles in proliferating pure electric vehicles was always the inability for people to wrap their heads around the idea of an ever decreasing range (shinking gas-tank metaphor). It may not seem like too big of a deal now, but that’s in no small part to the fact that they worked so hard to minimize the effects of this, relative to the average life-span of a traditional internal combustion engine vehicle.

On top of that, Musk has been very vocal about his desire, and commitment to making Teslas into “million mile vehicles” with “minimal routine maintenance” during that time-frame… I think this further supports my belief that they’re being very conservative with the cells.

Consider, as another related point, the other similar-ish cells. Samsung 40Ts and Molicel p42as, we know very little about the cells themselves at this point, yet the insane continuous discharge rates of the p42as with slightly higher capacity come with greatly decreased cycle life if running those high discharges, and some specifics about thermals to maintain that. With higher sustained discharge rates, so drops capacity. So I wonder really how different these cells actually are, versus how the individual manufacturers/resellers are choosing to rate them, and treat them.

I guess it’s all speculation until we see someone put these Model 3 cells through a true torture test, but I’m hoping to see 15A cont no prob, and 30A pulse discharge to be reasonably sustainable, without any special cooling. Maybe I’m being optimistic though.

Got mine in from BB finally. Shipping took forever and they did damn signature confirm which really pissed me off tbh (messing up my beauty sleep, and fedex won’t schedule beyond “by 9pm on day X”), but they were well packed, and the cell holders are a nice extra if nothing else than ease of handling and bulk parallel charging.

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Really good info, I agree I don’t think anyone would like seeing their car’s range drop a few miles a year considering how long the lifespan of cars generally is. We just take for granted the range losses in our boards because it doesn’t matter as much

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I was reading that model 3 cells have a lower flash point than other well know cells due to chemistry. Also the need for all that heatsink glue and active ac cooling. Should my new build allow for airspace between cells…a fan…passive air cooling …thermal heat sink silicon intead of clear aquarium stuff??? Or just do it the same old way and seal it all up b/c I dont know how to put heat sinks on parallel packs

even on “ludicras mode”, how long are they really drawing the batteries at 20a?
I’d say less than 5 secs tops because most of the current draw is used during the initial acceleration. It takes very little current to sustain even high speeds.

So 20a “burst/peak” is very realistic

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6 wide fits quite well

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@Fosterqc
What are you planning 12s?

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For our use it hardly matter, unless you charge and use it everyday and can’t afford a new battery every two years

All that cooling is mostly to be capable of doing the ultra fast charging they do, and actually not cooling, but heating the cells to 50+°C prior a charge session

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So 150-180 degrees vs. 350 degrees doesn’t bother you atleast alittle