Thinking about a Tesla truck

[Midpack]

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Originally Posted by ERD50 Good luck on finding one at $39,900. I still don't see the promised $35,000 Model 3, and the tax credit is running out soon, raising the effective price by $7,500 over when that promise was made.

It’s come and gone, you missed it.

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February 2019: Tesla announced that the $35,000 Model 3 was finally available to order. It was said to be a stripped-out version of the Model 3 with cloth seats and a "Standard Interior" configuration with few standard features, priced starting at $36,200 ($35,000 plus a $1200 destination charge). April 2019: Tesla removed the Model 3 Standard Range from its online ordering system and announced that it would be a special-order-only model available only at physical Tesla stores. The company also said that the Standard Range model would now be a software-limited version of the Standard Range Plus with the "Partial Premium Interior" and with certain features locked out, rather than the previously announced model with cloth seats and a "Standard" interior setup.

One of many sources last Spring https://www.caranddriver.com/news/a2...-price-change/

[Mr. Tightwad]

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Originally Posted by ERD50 Any EV (or hybrid) relies on regenerative braking. That is, it runs the motors as generators, which creates a drag on the car, and captures that energy to charge the batteries, instead of wasting it by turning it into heat as traditional friction brakes do. But if the battery is already near full charge, it may not be able to absorb this extra energy from braking. In an ICE car/truck, you downshift and use the engine for braking. On a long downhill grade, you can burn up your brakes if you don't do this. Or sometimes overheat them to the point that any residual moisture in the brake fluid turns to steam, which is compressible, and renders the brakes near useless. So going down a long grade in an EV with a near full battery could be problematic. And in this context, "problematic" means: "Oh cr@p!!!! I don't have any brakes, and I can't downshift!!!". -ERD50

Incorrect. One would go down the long grade and simply apply the regular brakes. Same as you would an ICE car. When the battery is full in a Tesla, a notification appears on your monitor that "regenerative braking is limited". So you don't capture the energy to charge the battery while driving until the battery lowers its full charge.

The standard brakes in an EV are the same as an ICE car.

[Mr. Tightwad]

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Originally Posted by Midpack Are you kidding Mr T? And this doesn’t show all the prior losses. Revenue up, still thin margins or losses - Model 3 bump is over, and I’d be surprised if the (goofy) truck helps. Model Y? I’d say way too soon to tell, until the next recession maybe.

I'm referring to the folks from that thread who stated Tesla would soon be toast. Yet here we are, 2 or 3 years later, and we are watching more models being released. More factories being built (Germany being the newest location designated to get one).

Several forum members were quite skeptical about Tesla's survival. I haven't heard anybody admit they were wrong.

[Fermion]

You could also turn up the radio really loud to drain the battery while you are going downhill.

[btdt22]

I like people/companies who think outside the box. Space X and Tesla are a great example. Ordered a Tesla cyber-truck for my wife two days ago

[Sunset]

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Originally Posted by cyber888 The top level version can achieve 500 miles of driving on one charge and tow 17,000 lbs. It can also go from 0-60 in 3.4 seconds, faster than a low-entry Ferrari. And the body cannot be dinged by a sledgehammer. And it has Full Self-driving capability. at $69,900. Well, there was a niche market that bought the big Hummer when it came out at $100,000+. Why not. The front lights of the Cybertruck looks like the Knightrider car. I would buy it - if I need a truck, because the chassis can't be dinged, and it does not need gas at all. But I'm a station wagon guy (never SUV), so that 600 Horsepower Audi Beast of a Wagon is a ice catcher. https://www.motortrend.com/news/refr...di-rs-6-avant/

FIFY.
Quoting the price of the one representing all the features described.

[Fermion]

For the three motor truck to have 500 miles of range, it must have at least a 200kWh battery in it, maybe 250kWh.

Those of you who have installed a backup generator for your house have wasted $15,000 or so. A 250kWh cybertruck would power your house for days with no noise or maintenance.

[travelover]

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Originally Posted by Fermion You could also turn up the radio really loud to drain the battery while you are going downhill.

My Escape hybrid would spin the engine really fast off the generator power if the battery was full and descending a steep grade. Of course with no engine in an an all electric car, you can't do that.

[ERD50]

RE: $35,000 M3 -

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Originally Posted by Midpack It’s come and gone, you missed it. One of many sources last Spring https://www.caranddriver.com/news/a2...-price-change/

Yes, I was aware it was available for a short time, which is consistent with my "good luck in finding the truck at $39,900".

Though doing some searching, it appears you can buy a $35,000 M3 if you call them or go into a store, they just don't have it on their web site. I think there were some other 'downgrades' they did t make it less attractive, but $35,000 is $35,000. Tesla seems to be burying it, as I assume the profit margin (if any) isn't helping them. That's OK, but it's just not going to happen at the volumes all the EV sites were excited about when it was announced.

So yes, with the time frames on that truck, I suspect it will be a very long time, if ever, that
you can buy one at $39,900. Or that it would be configured such that you would want to buy on at that price.

-ERD50

[aja8888]

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Originally Posted by cyber888 The top level version can achieve 500 miles of driving on one charge and tow 17,000 lbs. It can also go from 0-60 in 3.4 seconds, faster than a low-entry Ferrari. And the body cannot be dinged by a sledgehammer. And it has Full Self-driving capability. Starts at $39,900. Well, there was a niche market that bought the big Hummer when it came out at $100,000+. Why not. The front lights of the Cybertruck looks like the Knightrider car. I would buy it - if I need a truck, because the chassis can't be dinged, and it does not need gas at all. But I'm a station wagon guy (never SUV), so that 600 Horsepower Audi Beast of a Wagon is a ice catcher. https://www.motortrend.com/news/refr...di-rs-6-avant/

I thought all their vehicles has this feature (full self driving capability)? Level 5, Correct? How's that been working out?

[Fermion]

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Originally Posted by travelover My Escape hybrid would spin the engine really fast off the generator power if the battery was full and descending a steep grade. Of course with no engine in an an all electric car, you can't do that.

I was obviously joking but realistically they could have some sort of power dump. A air or water cooled resistive load somewhere. Honestly though I doubt there are that many times that your battery would be at 100% while traversing steep grades, unless you just have a 8% grade right out of your home driveway. Most people would leave a supercharging station before filling up completely to 100%.

[ERD50]

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Originally Posted by Mr. Tightwad Incorrect. One would go down the long grade and simply apply the regular brakes. Same as you would an ICE car. When the battery is full in a Tesla, a notification appears on your monitor that "regenerative braking is limited". So you don't capture the energy to charge the battery while driving until the battery lowers its full charge. The standard brakes in an EV are the same as an ICE car.

Sorry, but you are the one who is incorrect. In a regular ICE car, you downshift and let the engine do most of the braking. You can do that with a full tank of gas, or a near empty one.

"simply applying the regular brakes" is what leads to the problems I mentioned - hot, faded brakes, water in the brake lines turning to steam, excessive brake wear, etc.

Do a search on the topic, and you will find plenty to support my claim

https://www.centralaveauto.com/downs...ng-down-hills/

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The reason that you want to downshift is to protect the brakes. When your brakes are applied, they create friction, and this friction is what slows the vehicle down. But friction also creates heat, and too much heat will damage the brakes. Too much heat can also make brakes completely fail. Brake failure happens when brake fluid gets too hot and starts to boil. When brake fluid boils, brake pedal fade will occur, or complete brake failure can happen while driving downhill. A vehicle’s downhill speed will increase due to gravity. Heavier use of the vehicle’s brakes is needed in order to slow down the vehicle’s progress. Under heavy braking, brake fade can occur. Brake fade is a result of overheating and reduces friction between the brake pads and discs. When brake fade happens, it reduces the effectiveness of the brakes, which is dangerous and often more common in larger vehicles. The good news is that you can descend down most any hill without ever using your brakes. This is done by a method of “downshifting,” or selecting a lower gear. This method uses the vehicle’s drivetrain to slow the vehicle. .

-ERD50

[Fermion]

I never really thought about exactly where the energy is being dissipated in a ICE car when using engine braking.

Say it takes 20kW to slow down your heavy truck + trailer on a steep grade.

I guess if you have a large displacement V6 or V8, the energy is dissipated by the engine block and cooling system as the back driven pistons compress air to slow down the vehicle?

This would indicate that a electric vehicle could also dissipate this energy with some sort of air cooled or water cooled resistive load....although adding complexity of course.

My tiny displacement 2.7L turbo ecoboost engine in my F150 4x4 has nearly zero downshifting braking ability. The engine quickly revs up to near redline rpm when you try to go down a steep grade in 2nd or 3rd gear and 1st gear only lets you go like 10mph. So it isn't just electric vehicles that have issues. Modern high efficiency small displacement ICE engines do as well. My 2.7L turbo can put out over 300hp, it just can't brake.

[travelover]

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Originally Posted by Fermion I was obviously joking but realistically they could have some sort of power dump. A air or water cooled resistive load somewhere.........

Now that you mention this, at MegaMotors we had trailers that had generators powered off the trailer wheels and huge resistors with heat dissipaters. These were used to simulate pulling a trailer up a grade during durability testing.

[ERD50]

Quote:

Originally Posted by Fermion I was obviously joking but realistically they could have some sort of power dump. A air or water cooled resistive load somewhere. Honestly though I doubt there are that many times that your battery would be at 100% while traversing steep grades, unless you just have a 8% grade right out of your home driveway. Most people would leave a supercharging station before filling up completely to 100%.

True it is not a common problem at all. But some are trying to say it doesn't exist, which is not true.

IIRC, one of the Tesla executives actually did live at the top of a long, steep grade, and he got the warnings that his regen braking was limited each time he left home. I'm pretty sure you can tell the Tesla to only charge to X% at home, so that would solve the problem for him.

So not a big issue, but to deny that it is an issue is fantasy.

But now I'm curious how this works. IIRC, fast charging tapers off at ~ 80% full? So would he need to charge enough below 80%? OK, a quick search found one person saying no regen above 90% (not sure that's reliable, but I'll take it for now). But that guy would need to go below that to allow some 'room' as the regen added charge. So he can't be above 90% a short ways from home. Again, not a big deal - but it is a deal. His Tesla effectively has ~ 10% less range than he paid for (when leaving from home).

-ERD50

[Fermion]

Maybe a software only fix! Allow the heater and the air conditioner to both be on at the same time in a Tesla during braking.

[ERD50]

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Originally Posted by Fermion I never really thought about exactly where the energy is being dissipated in a ICE car when using engine braking. Say it takes 20kW to slow down your heavy truck + trailer on a steep grade. I guess if you have a large displacement V6 or V8, the energy is dissipated by the engine block and cooling system as the back driven pistons compress air to slow down the vehicle?...

Yes, and I assume much of that hot compressed air just goes out the exhaust.

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Originally Posted by Fermion ... This would indicate that a electric vehicle could also dissipate this energy with some sort of air cooled or water cooled resistive load....although adding complexity of course.

Electromotive diesel trains do exactly that. They have big resistor packs to absorb the energy. You'd think the start-stop commuter lines could make use of batteries just like a hybrid car, not sure why this isn't being done on a larger scale?

https://www.escomponents.com/what-are-braking-resistors

-ERD50

[dirtbiker]

On the plus side, I'd imagine that a nearly fully charged electric car going down a steep hill requiring regenerative braking would be a fairly uncommon occurrence in everyday use, unless there is a large downhill very shortly after a trip begins, in which case it would require prior planning and leaving with a less than fully charged battery. A software fix allowing heat and AC, as fermion suggested, is a good idea as a possible workaround that would work in many instances.

[NW-Bound]

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Originally Posted by dirtbiker But how often does a situation like this actually happen? This reminds me of a guy who never wore his seat belt. His reasoning was that he didn't want to get trapped in the car if he ever crashed into the water. This being said, I would like to See Tesla address this issue somehow. But if given the option of 'unbreakable' glass in any vehicle, I'd gladly take it.

I like unbreakable glass too, if I have a door that I can open.

In normal cars, even with electric door locks, you can open the doors from inside to escape. In Tesla cars, the computer controls everything, and if the computer dies in a crash, the front doors can be opened manually, but not the rear doors.

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The Tesla Model 3 does not have a mechanical latch for rear passengers at all. Tesla says front passengers are meant to use the physical latch on their doors to get out, then to open the door from the outside for the rear occupants in the event of a power loss. With incapacitated passengers in the front seat and a loss of power, the lack of a mechanical release could trap otherwise capable passengers, though...

Front passengers to get out and to open doors for rear passengers. But what if the exterior door handles are still retracted?

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The Model X has those funky falcon doors that slowly rise up electronically, and it's not particularly easy to escape out of them in a crash where power is lost. You have to pry the rear speaker grille off, then pull a metal wire behind that grille toward the front of the car to manually release the door. Then you're forced to shove the extremely heavy falcon door up to get out. But what about crawling to the front seat, you might ask? Well, depending on the severity and location of the damage, getting to the front seat might not always be an option. And we don't imagine many backseat passengers know about the secret mechanical release.

[NW-Bound]

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Originally Posted by Chuckanut That is something I did not think about. Or, in making the prototype, they put in ordinary glass, never considering that the Big Boss would actually throw something at it. OTOH, Mr. Musk is famous for his make it, test it, fix it way of designing products. So, maybe we simply witnessed another test.

On the Web, I saw a video of a test inside Tesla before the product reveal. A guy threw a steel ball at the window and it did not break.

Perhaps the thrower at the public show was a stronger guy, or he threw faster, or he grabbed a ball that was heavier than the one used previously.