On second thought: my guidance was probably too harsh, so go ahead and discuss the Cyberquad. But don't go overboard.
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Tesla, TSLA & the Investment World: the Perpetual Investors' Roundtable
- Thread starter AudubonB
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Krugerrand
Meow
No need to ask any questions. If he’s a friend simply tell him he does not own enough TSLA.In an amazing coincidence, I am going to be chatting today with a battery research engineer friend who happens to work for, wait for it...
VW
What should I ask this person?
Good, cuz I wasn't sure where I could park it.It's sold out already, we waited too long to discuss it!
All of this Cybertruck swag was probably meant to roll out along with the start of deliveries. I give it a small chance though that we either get word of when production starts or perhaps that production has just started.
Regardless, I expect the final design to be unveiled very soon.
Regardless, I expect the final design to be unveiled very soon.
Just piecing some information together.
Tesla rejected a $1B+ incentive in Berlin, for which part of the conditions was that the factory must be the first to utilize 4680 cell.
Now we are bombarded with CT merchandises and hints that something big may happen on 12/9. Could it be Elon decided to use the current 4680 cells in production on limited CT production, which would prevent them from going to Berlin?
Tesla rejected a $1B+ incentive in Berlin, for which part of the conditions was that the factory must be the first to utilize 4680 cell.
Now we are bombarded with CT merchandises and hints that something big may happen on 12/9. Could it be Elon decided to use the current 4680 cells in production on limited CT production, which would prevent them from going to Berlin?
BrownOuttaSpec
Active Member
It's a toy, not made/produced by Tesla. It is made by Radio Flyer (same people who made the mini Model S and Model Y), I feel very confident in saying that there is zero Tesla tech in this product: Ride-On Tesla Toys for Kids | Radio Flyer
I think you were correct in your original guidance of moving it to its own thread. If not, why dont we add the Hot Wheels RC Cybertruck and the Lego Cybertruck.
Let's keep the discussion about it over at the proper thread: Cyberquad for kids
SOLD OUT
.. since we are now allowed to discuss
Tesla Toys needs it's own SPAC and IPO
The quad goes uphill as well .. Nikola
Even just getting it started in very low production would be huge. Tesla does have a history of seeding the market with low numbers to get buzz going (see model Y shipments to Europe).
Um. That's a little odd.
ADC's come in various "bit" sizes: 8 bit, 12 bit, 16 bit, etc. They'll typically have a precision reference voltage (band-gap diode reference or something) hooked up to the top of a resistor chain and ground or something at the bottom of said chain. An 8-bit ADC can measure 256 possible values, plus or minus the usual inaccuracy. But 8-bit ADCs are relatively uncommon; the cost difference between an 8-bit, 12-bit, or 16-bit ADC is minimal, so people usually go for the 12-bit (4096 values) or 16-bit (65536 values). The bigger bits are slower, typically, than the smaller bit types, but we're talking typical sample rates of 1 MSa/s and up for the cheapies, and I'm pretty sure that a BMS doesn't need to know state of charge on a microsecond-by-microsecond basis. (Now, if you want to sample along at 10 GSa/s, then you might be restricted to an 8-bit ADC, but that's a different story.)
Further, I suspect you're not going to find very many people willing to sell you an ADC that takes in 800V directly; that's a good way to end up with silicon vapor. Typically, one uses a resistor divider so the maximum input voltage to the ADC is 80% of the maximum for the ADC. (And the accuracy of the measurement is directly related to the accuracy of the resistors; in an application like this, one would need to use matched resistors, built on the same substrate, around .1% accuracy, typically, without spending too much money.)
So, to measure 800 V, we'd divide this down to 80% of the maximum of the ADC, then measure. So, using a 12-bit ADC, we'd have 800/(4096*0.8) = 244 mV/step; with a 16-bit ADC, that'd be 800/(65536*0.8) = 15 mV/step.
First off: in my extremely uneducated BMS opinion, 244 mV or 122 mV (for a 400V system) seems too large to keep track of the voltage on a battery chain; for sure, if one was monitoring the overall battery voltage, 16-bit and 15mV (or 7.5 mV for a 400V system) seems to be the way to go. Now, if I can figure this out without an envelope, so can anybody else.
Second: I dunno if Porsche (or Tesla, or whomever) is running every single battery cell in series (unlikely in the extreme) or all in parallel (impossible if one wants high voltage), or some combination of series and parallel (a lot more likely), the individual voltages that the BMS would be monitoring would be individual cell voltages or smaller groups of cells, then do some math to add it up to the overall battery pack voltage (if desired). Remember: They're trying for the amount of charge on cells, I would think. But that means that the voltages they're measuring would be, for the Porsche, 800/N, where N is the number of series groups.
Which means that my step sizes up above would also be divided by N. So, for example, there's 10 bunches of cells in series, with 80V across each bunch, then a 12-bit ADC on that bunch would have 244/10 = 24.4 mV/step. Which is probably getting down to the point where a 12-bit ADC would be doable.
Conclusion: This ain't rocket science, at least not for a practicing EE. So, while it sounds like a nifty idea (ADC mistake!), it's probably not that. Sorry.
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Amazing number considering how many more boats left Shanghai so far this quarter. Aug (2nd month of quarter was like 31k), so I’m expecting at least 35k exports minimum but I think 40k is more likely
Um. I agree with you about cutting blocks of cells in/out of a group in parallel. But I have a quibble about voltages and such and where they come from.
I've formed an opinion (probably wrong, but who knows?) that the actual battery charger in all these BEVs is some form of DC-DC converter, running at $DIETY's own switching frequency. Input side would be DC from the car's on-board AC->DC converter or direct DC from a charger. Output side would be the DC voltage and current used to charge the battery. These things are highly efficient in their power conversion, especially with relatively high voltages on input and output.
I mess with these things from time to time at work on a regular basis, although admittedly the outputs are used to power up silicon, not batteries. Having said that, though: I haven't run into one of these in the past decade or two that doesn't have the capability of measuring both its output voltage and current; and, even if one had some kind of home-brew circuit that didn't have the output V and I monitoring built in, it's truly trivial to add that after the fact; Hall-effect current sensors are out there and are cheap, not to mention just measuring the voltage across a low-value resistor.
In principle, then, an electron shouldn't be able to fall in the woods without somebody/something noticing.
I suspect that the problem with Porsche's BMS, assuming the whistleblower is onto something, has nothing to do with basic monitoring. Since I got the Tesla, I've been reading the odd papers here and there posted online about different battery chemistries, longevities, anode and cathode structures, and all that. I'm not an expert, by any means, but the algorithms used to charge/discharge the batteries in a BEV look to be very, very challenging, and, if one gets those wrong, then, yeah, the whistleblower may be onto something.
CLK350
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