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Tesla created secret team to suppress thousands of driving range complaints

reuters.com

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Re: Tesla created secret team to suppress thousands of driving range complaints

#761

Post by tehwebguy »

concordDance wrote: post #657
tehwebguy wrote: post #214

Earlier quoted context omitted.

We rented one on a trip recently, super annoying to realize the dozen or so chargers in this beach town were actually incompatible or just too slow for real life. On the way back to the drop off autopilot tried to slam us into the Bentley next us! It had been traveling the same direction as us for like 20 minutes and when we passed through an intersection it just jerked hard left and I had to correct it manually. Pos…

> We rented one on a trip recently, super annoying to realize the dozen or so chargers in this beach town were actually incompatible or just too slow for real life. Where were you that has a dozen chargers but no superchargers?

New Smyrna Beach, I drove to Daytona to charge. Not a terrible distance but an annoying for sure.

One other thing, for days on end the navigation would never “engage” just stuck on something like “Starting route.” So it never started conditioning the battery on the drive (and even chastised me for not doing so!?)

Finally, one morning all miles measurements were replaced with kilometers and it took watching a youtube video to figure out how to change it back.

Re: Tesla created secret team to suppress thousands of driving range complaints

#762

Post by stetrain »

itsoktocry wrote: post #451
stetrain wrote: post #131

Earlier quoted context omitted.

Are you talking about the battery meter? That is just EPA range * battery percentage. The precise estimate is in the navigation system, when you navigate to a destination and it says you will arrive with X% left. This takes into account speed, traffic, elevation, temperature, wind, etc. and is usually pretty accurate for me.

> This takes into account speed, traffic, elevation, temperature, wind, etc Can you expand on this? You say etc, what else is included? Where is it documented that this calculation is actually happening, versus something far simpler?

“The calculation that predicts how much energy you will use is an estimate based on driving style (predicted speed, etc.) and environmental factors (elevation changes, wind speed and direction, ambient and forecasted temperatures, air density and humidity, etc.). As you drive, Model 3 continuously learns how much energy it uses, resulting in improved accuracy over time. It is important to note that Model 3 predicts energy usage based on the driving style of the individual vehicle. For example, if you drive aggressively for a period of time, future range predictions will assume higher consumption.”

https://www.tesla.com/ownersmanual/model3/en_gb/GUID-01F1A58...

Also if you open the Energy app in the car it will show you which of these factor(s) are contributing to higher or lower consumption than the navigation’s estimated range as you go.

Re: Tesla created secret team to suppress thousands of driving range complaints

#763

Post by stetrain »

bumby wrote: post #558
jodrellblank wrote: post #423

Earlier quoted context omitted.

"unless you chart a specific trip"

So the implication is it's getting it's data from local weather stations and not from the vehicle itself, no? If anyone know, I'd be interested in the more details and what led to that decision.

It can’t know you are planning to drive over a mountain unless you put that in the nav system.

Re: Tesla created secret team to suppress thousands of driving range complaints

#764

Post by stetrain »

lldb wrote: post #305
pjc50 wrote: post #250

Earlier quoted context omitted.

> slow is fast, keep it at 60 if you want the milage meter to not die as quick This also works in petrol cars: the air resistance efficiency falloff is dramatic at higher speeds.

However, ICE is more efficient at higher free speeds unlike electric so there’s a higher sweet spot.

More so that ICE has really bad efficiency at city driving due to lack of regen braking and engine idling.

EVs (and hybrids) with regen braking remove this lost efficiency in city driving, leaving you with an energy usage curve that scales more directly with aerodynamic drag due to speed.

EVs are more efficient at low and high speeds than ICE, they just have small “gas tanks” so the high speed losses are more noticeable.

Re: Tesla created secret team to suppress thousands of driving range complaints

#765

Post by stetrain »

dinom wrote: post #515
Reubachi wrote: post #449

Earlier quoted context omitted.

It's not about weight or incline, it's the mechanical gearing in the "transmission" that can't turn the wheels without 100 percent power from the engine. You'll be able to push it and think it's really heavy, but it's just the transmission fighting you. standards and automatic trans have neutral that disconnects driveshaft from engine, removing any resistance from the engaged gear. Most EVs either don't have neutral…

> Most EVs either don't have neutral or a poor implementation of it, I'm sorry, do you mean that neutral and "car wash/freeroll mode" are not 100% equivalent? This really confounds me... if my car has a problem while driving down the road, I'd really like to have a chance of pushing it onto the shoulder if necessary. A car that you can't do this with sounds very poorly designed to me.

They aren’t equivalent. Most EVs have a free roll mode, where you can push the car or take it through a car wash. You are still spinning the electric motors though.

This is fine for low speeds and short distances but is not advised for towing, like with tow trucks that leave two of the car’s wheels on the ground.

Re: Tesla created secret team to suppress thousands of driving range complaints

#766

Post by efreak »

somat wrote: post #598
dghlsakjg wrote: post #436

Earlier quoted context omitted.

Slight nitpick: Using heat won't affect gas consumption of an ICE car. The heat is waste heat that otherwise would be dissipated through the radiator at the front of the car. Turning on the heat diverts coolant to a heat exchanger (tiny radiator) in the ventilation system that warms the air in the cabin.

However note that sometimes the A/C will be on at the same time as the heater in order to dry out the air. This is one of those stupid facts that lives rent-free in my head. "If you want 'dry' hot air you need to dry it before sending it to the heater. The primary purpose of the A/C is to dry the air(this also happens to cool it), there is already an A/C unit in the ductwork, profit" But I decided to fact check mysel…

Regarding conditioning/drying the air instead of cooling it: the first modern air conditioners were invented primarily to dry the air, cooling was a side effect. The term "air conditioner" itself originally referred to moisture content as I understand it.

Re: Tesla created secret team to suppress thousands of driving range complaints

#767

Post by anticensor »

colejohnson66 wrote: post #615
giobox wrote: post #465

Earlier quoted context omitted.

> Is it...not just going into neutral via disconnecting a drive shaft? Conceptually you are correct its like neutral, but almost no EV from any manufacturer has disconnecting drive shafts. Every Tesla model except the original roadster is locked in a single gear transmission that never disconnects - one of the big reasons EV drivetrains can be built so reliable with virtually no maintenance requirements (there is no…

If the drivetrain never disengages, how does “freewheeling mode” (neutral) work? Spinning the wheels manually makes them a generator, and that causes resistance from the magnetic flux (hence regenerative braking). How do cars disable that?

It disconnects the excitation current.

Re: Tesla created secret team to suppress thousands of driving range complaints

#768

Post by anticensor »

CryptoBanker wrote: post #346
sneak wrote: post #199

Earlier quoted context omitted.

It's likely that you waived your rights to a class action against Tesla when you agreed to some EULA.

And that clause will never be enforceable in court

There is a way to act against that too: "whatever is decided in court, if anything deviates from the spirit of this contract's full enforcement for any reason within either party's control, both parties are fully liable for undoing every part of their performance, including refunding all the products and services."

Re: Tesla created secret team to suppress thousands of driving range complaints

#769

Post by klaff »

AnimalMuppet wrote: post #599
klaff wrote: post #351

Earlier quoted context omitted.

Force is proportional to square of speed but power = force*speed so proportional to speed^3.

That's not how this works. First, the force that is proportional to the square of the speed is the drag force, which means it's the force you need to supply just to keep the speed from dropping. Power = force * speed is a different "force" - it's the force produced by the engine. Second, power output of an engine typically has an RPM where it peaks. Past that point, more speed means less power output, which means muc…

It's exactly how it works and the math is not complicated.

Suppose you have a vehicle w/ 3 m^2 frontal area, drag coefficient of 0.3 and it's travelling at 30 m/s. Using this calculator https://www.symbolab.com/calculator/physics/drag-equation you can find that will require about 500 N of force (use density of 1.225). The power at that operating point is the product of speed and force, or 30 m/s * 500 N = 15 kW.

Now let's change the speed to 40 m/s. That bumps the force to about 900 N. Now we would calculate power as 40 m/s * 900 N = 36 kW.

Changing these numbers to horsepower we get 20 hp and 48 hp.

The force goes with the square, the power goes with cube. There are assumptions here - for example, if you have a headwind this statement is no longer true because the speed in the drag equation is the air speed of the vehicle (goes up with headwind / down with tailwind) but the third speed factor is the ground speed of the vehicle (because that's based on the physics "work is equal to force times distance" and power is the rate of work).

The graph of an internal combustion engine's power at wide-open throttle vs. engine speed is irrelevant, unless you are trying to figure out which gear ratios would let the engine make enough power to drive the vehicle under those conditions.

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