Tesla, TSLA & the Investment World: the Perpetual Investors' Roundtable

[kyzhk]

Nope, can't work. Supercapacitors have a nearly linear voltage curve from 100% SOC to 0%. Lithium ion batteries have a nearly flat voltage curve for the greater part of their discharge curve. So that means only a tiny portion the Supercap's (already meager) stored energy can be used to buffer the lithium cells. From an engineering perspective, the weight, space, and cost are ALWAYS better spent simply on a bigger lithium battery.

Jack Rickard spent $10,000 on a homemade prototype with Maxwell caps as a boost pack for a lithium battery. It weighed more and performed worse than the plain battery of equal weight, but cost much more.

Finally, the cell cycle life and storage degradation rate of the ultracaps can NEVER match the rate of the lithium battery its paired with, further complicating the task of trying to combine their performance specs in any useful way.

TL;dr Ultracaps don't play well with lithium batteries.

Agree with the conclusion. Just want to point out one thing - buck boost converter is a thing. It allows DC-DC voltage conversion: in a boost configuration, it can step up DC voltage by utilizing the back emf developed across inductor at high rate of change in current due to rapidly switching on and off a electrical switch (such as mosfet). How much to boost can be adjusted by adjusting the duty cycle on the mosfet (and adjusting inductance... but easier to adjust mosfet duty cycle)

 

[Artful Dodger]

Agree with the conclusion. Just want to point out one thing - buck boost converter is a thing. It allows DC-DC voltage conversion: in a boost configuration, it can step up DC voltage by utilizing the back emf developed across inductor at high rate of change in current due to rapidly switching on and off a electrical switch (such as mosfet). How much to boost can be adjusted by adjusting the duty cycle on the mosfet (and adjusting inductance... but easier to adjust mosfet duty cycle)

Rube-Goldberg approved.

BTW, what's the weight and cost of a DC-DC converter that can handle 2000 amps at 400 volts?

Cheers!

 

[Beltsbear]

How long until there is enough pack production with 2170 cells to cover all cars (S3X)?
Surely the S & X will get the 2170 cells before the Y

The S/X do not need 2170's. A refresh could include a new motors (reluctance) and new control electronics. Those changes could improve charging times and compatibility with V3 charging as well. There is nothing wrong with the 18650 format other than it is slightly less energy dense then the 2170's.

 

[kyzhk]

Rube-Goldberg approved.

BTW, what's the weight and cost of a DC-DC converter that can handle 2000 amps at 400 volts?

Cheers!

well, it was more of a possible vs impossible rather than an engineering discussion on this quote since you didn't provide disclaimer:

Lithium ion batteries have a nearly flat voltage curve for the greater part of their discharge curve. So that means only a tiny portion the Supercap's (already meager) stored energy can be used to buffer the lithium cells.

 

[Tim S]

Lol at the downvotes. Just cuz the echo chamber thinks Elon is god...doesn't mean Tesla is well managed. Elon's an engineer, not a manager. He actually sucks, yes, sucks at managing. Probably Tesla's greatest weakness. Just look at the S&$-_+ show with the store closings announced with model 3 $35k and now they're backpedaling that.

The Trump supporter thinks Elon is a bad manager. Ha ha.

 

[Beltsbear]

Nope, can't work. Supercapacitors have a nearly linear voltage curve from 100% SOC to 0%. Lithium ion batteries have a nearly flat voltage curve for the greater part of their discharge curve. So that means only a tiny portion the Supercap's (already meager) stored energy can be used to buffer the lithium cells. From an engineering perspective, the weight, space, and cost are ALWAYS better spent simply on a bigger lithium battery.

Jack Rickard spent $10,000 on a homemade prototype with Maxwell caps as a boost pack for a lithium battery. It weighed more and performed worse than the plain battery of equal weight, but cost much more.

Finally, the cell cycle life and storage degradation rate of the ultracaps can NEVER match the rate of the lithium battery its paired with, further complicating the task of trying to combine their performance specs in any useful way.

TL;dr Ultracaps don't play well with lithium batteries.

Thats not really true. With the right sizing (small supercaps) it would work quite well. Just enough supercap to take in a city braking regen. That would reduce wear on batteries and allow taking in regen when the battery is cold and can't. It would also allow for one fast start every few minutes. Doing all of this with not much space taken up. The problem is cost and complexity, so it is not necessarily right for every application or price point.

 

[omarsultan]

Surely the S & X will get the 2170 cells before the Y

IMO, the current generation S and X will never see the 2170. There is too much rework that would need to be done for no material gain--resources are better invested in the growth platforms. I know others will passionately disagree with this.

 

[MarcusMaximus]

The S/X do not need 2170's. A refresh could include a new motors (reluctance) and new control electronics. Those changes could improve charging times and compatibility with V3 charging as well. There is nothing wrong with the 18650 format other than it is slightly less energy dense then the 2170's.

Is the improved cooling on the 3’s packs unrelated to the 2170’s? Seems that’s what’s allowing 250kW supercharge rate, which is why I ask.

 

[Pezpunk]

How long until there is enough pack production with 2170 cells to cover all cars (S3X)?
Surely the S & X will get the 2170 cells before the Y

Elon has answered this question in the negative so many times, he has trouble hiding his irritation when saying there are no plans to put 2170s in the S or X. i think at this point he will go to his grave before putting 2170s in the S and X. so, don't hold your breath.

 

[TradingInvest]

Model Y doesn't have side mirrors? That would be great.

Tesla posted a picture on the website, it seems the Model Y indeed has no side mirrors. This is really good.

 

[omgwtfbyobbq]

Nope, can't work. Supercapacitors have a nearly linear voltage curve from 100% SOC to 0%. Lithium ion batteries have a nearly flat voltage curve for the greater part of their discharge curve. So that means only a tiny portion the Supercap's (already meager) stored energy can be used to buffer the lithium cells. From an engineering perspective, the weight, space, and cost are ALWAYS better spent simply on a bigger lithium battery.

Jack Rickard spent $10,000 on a homemade prototype with Maxwell caps as a boost pack for a lithium battery. It weighed more and performed worse than the plain battery of equal weight, but cost much more.

Finally, the cell cycle life and storage degradation rate of the ultracaps can NEVER match the rate of the lithium battery its paired with, further complicating the task of trying to combine their performance specs in any useful way.

TL;dr Ultracaps don't play well with lithium batteries.

The linear voltage curve is what a boost/buck converter is for, but to be used effectively it likely needs to be integrated into the inverter.

 

[Nuclear Fusion]

Elon has answered this question in the negative so many times, he has trouble hiding his irritation when saying there are no plans to put 2170s in the S or X. i think at this point he will go to his grave before putting 2170s in the S and X. so, don't hold your breath.

Were the questions put to him framed in the short, medium or long term?

 

[CorneliusXX]

You’re probably right. But when I posted the sketchy Chinese site stating that Tesla’s were blocked from selling in China due to labeling, everyone said it was bogus. And then it turned out true. Sometimes the shorts have good info (at least the rational ones that I follow)

The problem is the magnitude placed on the issue. This was a small administrative error which happens in every company from time to time, is easily rectified and shouldn't even really be news. The shorts portrayed it as Tesla being locked out of the worlds biggest car market.

 

[Krugerrand]

Tesla posted a picture on the website, it seems the Model Y indeed has no side mirrors. This is really good.

So, the law changed recently? Or is it changing by the end of this year?

 

[anthonyj]

The problem is the magnitude placed on the issue. This was a small administrative error which happens in every company from time to time, is easily rectified and shouldn't even really be news. The shorts portrayed it as Tesla being locked out of the worlds biggest car market.

I know, I just posted the link because I thought it was relevant to the price action.

Side note:
TSLA | Volumebot
Short selling volume these past few days is hilariously low. Bears know that if they short here they can be incinerated by a tweet or two

 

[Fact Checking]

Tesla temporarily freezes store closures and layoffs in chaotic sales strategy change

For some unfathomable reason Fred failed to list three other obvious reasons why Tesla might have delayed the store closures:

• To give prospective customers who DO prefer a retail experience more time to use the stores,
• to delay the change by 3 weeks in the busiest 3 weeks of the quarter - which period of time by historic seasonal patterns handles as many sales as the whole quarter so far,
• to give affected retail employees time to find another position within Tesla, or to find another job.

Lol at the downvotes. Just cuz the echo chamber thinks Elon is god...doesn't mean Tesla is well managed. Elon's an engineer, not a manager. He actually sucks, yes, sucks at managing. Probably Tesla's greatest weakness. Just look at the S&$-_+ show with the store closings announced with model 3 $35k and now they're backpedaling that.

Actually, while Elon is far from perfect, the ability to change strategy quickly and then readjust and even cancel decisions on the fly without being worried about "losing face" is one of the greatest strengths of Elon.

Exactly because Elon knows that he is far from perfect, while he also knows the value of organizational agility.

I've seen so many successful companies go in a new strategic direction based on a well researched, well prepared, well communicated and well executed move which nevertheless was a bad idea that wasn't working, and then doubling down on that dumb idea, just because the CEO got married to the idea and didn't want to be seen "backtracking" and "losing face", and was also surrounded by sycophants who isolated him from honest feedback.

Donald Trump is perhaps the most egregious example of ego driven stubbornness and isolation from reality: of the literally thousands of hours of public utterings of Donald Trump you cannot find him admitting to a single mistake and apologizing for that mistake. My claim is easy to falsify: go on and give me a link to Donald Trump admitting to a mistake sincerely.

Trump's style of management resulted in 6 bankruptcies, including bankrupting a casino during the 90s boom (!) - which took some extra special skill...

Are you really making the argument that it turns people into cult members to approve of a management style that has resulted in great growth and zero bankruptcies, over a management style that resulted in 6 bankruptcies and performed worse than had Trump put all his inheritance into the S&P 500?

 

[MP3Mike]

Elon has answered this question in the negative so many times, he has trouble hiding his irritation when saying there are no plans to put 2170s in the S or X. i think at this point he will go to his grave before putting 2170s in the S and X. so, don't hold your breath.

I think it is mainly the charge port and wiring having been updated to handle the ~700A.

 

[X Fan]

My bet for an S/X refresh:

• Even longer range
• Heads up display
• Model 3 style dash and landscape touchscreen

Does a self-driving car really need a HUD?

 

[MarcusMaximus]

I know, I just posted the link because I thought it was relevant to the price action.

Side note:
TSLA | Volumebot
Short selling volume these past few days is hilariously low. Bears know that if they short here they can be incinerated by a tweet or two

Seriously, what is up with their fit function? That graph looks ridiculous.

 

[anthonyj]

Tesla posted a picture on the website, it seems the Model Y indeed has no side mirrors. This is really good.

The law states that a car must have side mirrors. They might be easily removable after purchase as Elon once suggested. Would help with drag