Investor Engineering Discussions

[MP3Mike]

And then someone did a 100%-0% drive and is claiming to have used 76 kWh, which doesn't make any sense either:

What makes you think that is a Model Y AWD? From what I can tell that is a Model Y Long Range AWD. (He has had it since early April.)

76 kWh makes sense for a LR.

 

[willow_hiller]

What makes you think that is a Model Y AWD? From what I can tell that is a Model Y Long Range AWD. (He has had it since early April.)

76 kWh makes sense for a LR.

Ah, yes. You're correct. It was quoted in a tweet thread about the Y AWD's battery pack size, but the context was definitely for a Fremont build. "new" in the tweet's context must be new to the current owner, not new variant.

 

[Stretch2727]

The efficiency improvement to get that sort of range from 50kWh in a Model Y is simply impossible. The Y is heavier and has worse cdA than the 3, it cannot be more efficient and certainly not that much more efficient. First principles logic.

Agree 100%. Some people speculating without a basic understanding of the physics.

Still would like to see confirmation of the weight of the 4680 cars from Austin. Some data showing they maybe lighter by 180 lbs or so. Would be nice to confirm you are getting something for the loss of 50 miles of range. 15% less range you would expect a weight saving of about 150 lbs if they just downsized the 2170 pack. I don't believe they have software locked the battery capacity.

Not to be negative but I don't think they have hit the target energy for the 4680 cells yet. The 4680 cells were supposed to have 5x the energy of the 2170. My math shows they are about 10% off the target.

At the same time they said there would be high nickel versions for the Cyber-truck and Semi only. These will likely hit the 5x target. So maybe the 5x was just for these cars and to keep the cost down on the cars that don't need the high energy density.

 

[mongo]

Not to be negative but I don't think they have hit the target energy for the 4680 cells yet. The 4680 cells were supposed to have 5x the energy of the 2170. My math shows they are about 10% off the target.

That's not being negative, that's what Tesla said on the Q1 call.

Still would like to see confirmation of the weight of the 4680 cars from Austin.

Twitter person took it to the scales and got 4220, but I can't find the Tweet now beyond it showing in Google results. So ???

 

[JRP3]

 

[Stretch2727]

Yeah saw that.

Just not sure how accurate these scales are when your not in the weight range of a large truck. I have done enough gauge R & R studies to know most measurement devices have some non-linearities.

Would be nice to see a LR on the same scale.

Even if it is 180lbs, it somewhat matches the weight of the scaled down 2170 pack so they have not increased the energy density.

 

[mongo]

There is another aspect of this that has been largely ignored. Well designed BEV wheel control systems are easily capable of very precise traction control. Off-roading makes those advantages glaringly obvious, as in the Rivian example.

Back in early 2016 I was driving an S70 to Crater Lake, Oregon. Overnight there was un forecast heavy snow. My rented S70 had summer tires RWD. It looked dire, more so since a Range Rover parked next to me was stuck. The Tesla had minimal slippage and extracted itself with relatively little drama. A week later a Tesla tech told me about the software that made that possible. Obviously that does not really make driving in very slippery conditions safe, it does reduce the risks substantially.

my lesson: a well designed purpose built pure BEV can have vastly better directional control and stability than can any ICE vehicle. That enhanced stability reduces wind risks, especially for, say, large articulated trucks. It reduces risk of losing directional control. And more, plus this is far cheaper than is ICE drivetrains.

We rarely discuss that set of issues. Those should be BEV standards, but cannot typically be with the BEV conversions of ICE vehicles.

Is that control advantage contributing to lower Tesla accident rates? Will it do so for Rivian too? It seems so to me.

That should be a focus for NTSB. ICE is dangerous! They catch fire easily, and have dangerously poor traction control! Ban ICE!

Critical factors are tires, weight on drive wheels, and the driver.
Other than Plaid, all Tesla vehicles rely on open differentials and braking for traction control. Yes, they have fast response on motor torque (PMSR is better than AC for this), but so can ICE cars via ignition pulling. Even ignoring that, brake modulation can override low ICE engine torque.

With dual motors (one front/ one rear), Tesla can act like a solid center diff while still allowing turns.

 

[JRP3]

Easy, turn off your house AC, go sit in your Tesla, turn on camp mode, and watch Netflix or read a book.

Build an interface which fits in a side window of your vehicle with flexible insulated duct work going to a house window, Tesla HVAC for the home. Use an inline duct fan for improved flow. Assuming you can park reasonably close to the house.

 

[mongo]

Build an interface which fits in a side window of your vehicle with flexible insulated duct work going to a house window, Tesla HVAC for the home. Use an inline duct fan for improved flow. Assuming you can park reasonably close to the house.

Yeah, I had that idea too
Need both source and return ducts.
Really fancy would be to tap into pack coolant loop, then route that to water-air heat exchanger in the house ductwork.
The easier thing is heating your garage...

 

[JRP3]

Need both source and return ducts.

I suppose it depends on how tight the house is, might be easier to just crack an upstairs window if needed.

Edit: Upstairs for cooling downstairs for heating maybe.

 

[mongo]

I suppose it depends on how tight the house is, might be easier to just crack an upstairs window if needed.

Edit: Upstairs for cooling downstairs for heating maybe.

I was thinking efficency wise, could put car on recirculate then instead of cooling hot outside air.

 

[JRP3]

Certainly more efficient that way.

 

[MC3OZ]

Specifically on V2G/V2H which was mentioned briefly in the main thread. (V2H = vehicle to house.)

For starters the car has to have the right type of battery which means a battery that is good for at least 4,000 cycles or V2G/V2H is only used in emergencies.

When V2G/V2H is used I think we only want a power output similar to level 2 charger say 250 V * 30 A = 7.5 kW, we don't want to overly stress any of the equipment or burn through the EV battery quickly.

For V2G the best way to stabilise the grid is with thousands of EVs plugged in, not a few EVs carrying the whole load.

For V2H if the gird is down, we want our EV battery lasting as long as possible, we don't want to burn through it quickly.

For V2H the household needs to be selective about what loads are running.

With these caveats it is a useful facility especially if a EV can provide an emergency Level 2 charging service to another EV. But the cost of the facility needs to be reasonable for the service it provides. Something like an extra $200 per car is reasonable, with $500 per car starting to look overpriced

 

[mongo]

Agreed and to put it more bluntly, they've either pushed to far with the limits of the drivetrain and were complicit, naive or ignorant. None of those are going to end well.

And I'd bet money there are several engineers who tried to stop it but we're overridden by managers.

For instance, we hired a few engineers who left ICE due to issues that fell on deaf ears before "dieselgate" broke.

@2daMoon, worse, accounting managers

Interacted with Ford in a previous life.
History is repetitive.

To hazard a guess, contactor was selected based on original car specs and packaged. Car came in over weight and under efficiency assumptions. To hit performance numbers, they had to over current the contactor (or at least, operate it in the less than continuous portion of the spec sheet). Then, they either read the data sheet wrong, miscalculated cooling rate, ignored thermal mass/ propogation, or used ideal new part values instead of worst case. May have not done a pick and hold circuit either.
Now they can't fit a larger part, so they need to cut vehicle performance/ throttle earlier.

 

[2daMoon]

I suspect that a significant factor in ICE OEMs development strategy has always been shaving costs of every part. A "penny wise, pound foolish" and incredibly short-sighted foundation to profitability. Thereby, increasing their profits while simultaneously making sure the vehicle's expected lifetime is kept to a range of years that equals the longest financing period available.

This peculiar balance between providing marginally higher profits and promoting a reduced product lifespan without any significant technological innovation (lagging tech standards by a decade, at least) has been the mainstay of these dinosaur-esque manufacturers. They have always seemed to me to be catering more toward their Union employees betterment, rather than bringing value to their customers.

Add to this how, despite government mandates and consumer feedback demanding them to innovate for several decades, they have rested upon the laurels of their past accomplishments, comfortable in the belief that what has always worked for them will continue to do so.

Hindsight now reveals how plodding along in pace with one another through one hundred years of operation has left them unprepared to compete with a company like Tesla that can actually apply modern technology to the design, manufacture, performance, and extended lifespan of their products with agility and surgical precision the legacy OEMs cannot match.

The band on the deck of their ship plays on as it's watertight integrity falters. Momentum alone seems to govern their future, and they are running out of it.

 

[nativewolf]

I think that ford has moved about as fast as any organization that size can move and there are bound to be issues with the first product . The original Tesla roadster has issues, the bolt had issues, etc. I am simply glad that Ford seems very intent in changing and even Elon recognized this the other day. They are late but there’s nothing they can do about it. You can only prepare for the future and they seem to be trying to do so. For instance they found the issue and have a solution and cars were not catching fire in garages. They plan to move to direct sales. The lightening is a hot product and I would Try to get one if I thought I could at sticker price.

Ford has a lot of learning to do but they are moving, more than any other OEM in my opinion.

 

[growler23]

I think that ford has moved about as fast as any organization that size can move and there are bound to be issues with the first product . The original Tesla roadster has issues, the bolt had issues, etc. I am simply glad that Ford seems very intent in changing and even Elon recognized this the other day. They are late but there’s nothing they can do about it. You can only prepare for the future and they seem to be trying to do so. For instance they found the issue and have a solution and cars were not catching fire in garages. They plan to move to direct sales. The lightening is a hot product and I would Try to get one if I thought I could at sticker price.

Ford has a lot of learning to do but they are moving, more than any other OEM in my opinion.

@nativewolf Having read your posts lately in the Roundtable, wanted to express my sympathy that you can't get a Cybertruck in time to meet your business needs. Could tell that really hurt. Damn sorry that is the case.

Now, for selfish reasons, I am still holding out hope that perhaps you can get lucky and nab an F-150 Lightning or two by hook or by crook, so that (when you undoubtedly report back) we here can get a deeper look at the pros and cons comparison to Tesla or at least a good feel for whether the most-likely-to-survive US "lagacy" manufacturer will indeed do so.

 

[nativewolf]

@nativewolf Having read your posts lately in the Roundtable, wanted to express my sympathy that you can't get a Cybertruck in time to meet your business needs. Could tell that really hurt. Damn sorry that is the case.

Now, for selfish reasons, I am still holding out hope that perhaps you can get lucky and nab an F-150 Lightning or two by hook or by crook, so that (when you undoubtedly report back) we here can get a deeper look at the pros and cons comparison to Tesla or at least a good feel for whether the most-likely-to-survive US "lagacy" manufacturer will indeed do so.

Thanks..yeah...it sucks actually. You could not design a better vehicle for our needs and frankly for almost any forestry business. The towing capacity is a downer but far offset by the tough exterior construction and crew cab and off road worthiness. Oh well. I can't afford the f150 on ebay, I thought of contacting Ford and offering to sell some trademark/design work they might be interested in from 2008 time period. I don't have the time to F with it though. Also, the f150 lightening is nice but not...tough, not stainless steel.

What we decided to do is get inexpensive gas trucks with 4wd but no frills, everyone gets one, save the F350s for moving fuel and work in the woods and fields. Then cross fingers the 4680 ramps faster and faster. They can be a few years old. Just to hold us over and keep miles and clients eyes off the ol beaters.

I'm very impressed with how well Ford has moved recently, hope they make it. The CT is still the best option for us but if the lightening were available without the markups we'd get 1 for sure.

 

[Buckminster]

 

[mongo]

Additionally, for V2G you really need VERY precise output regulation, because home loads vary a lot, and quickly (pop on the microwave and your AC at the same time and see what I'm talking about). This is exactly what Tesla's Gateway does to regulate input/output from the Powerwalls. Per above, this circuitry is not included in any meaningful way in the cars.

Minor point : V2H (islanding) needs tighter regulation. V2G can be slower and doesn't need to handle transients; but, that is trivial with digital control.

I don't see an AC home output from Tesla vehicles happening due to the extra UL requirements involved. DC to dedicated inverter/gateway/charger seems more likely (esp since the solar inverters can already handle 400V).