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You can push a tesla in most typical push situations. Sure its heavy, but its in the ballpark of pushing any large sedan or SUV, not just electric ones. You can
by giobox 3y ago
You can push a tesla in most typical push situations. Sure its heavy, but its in the ballpark of pushing any large sedan or SUV, not just electric ones. You can enable free-rolling wheels in the car and push away, especially if you have luxury of two people pushing.
The weight of a Tesla is not some unprecedented figure for a passenger car - a model 3 is no heavier than many BMW 5 series configurations etc.
The far bigger problem for pushing EVs in my experience is blown pyro-fuses that lock the axle after crashes preventing the wheels from turning - a common issue after an EV shunt. This is why you will often see EVs "dragged" out of shunts by the recovery vehicle until they can get the locked wheels onto dollies. This is only an issue if the EV being pushed has been in an impact generally, but the bar for a pyrofuse blow seems to be low too - it will trip even if airbags haven't deployed. The wheels on many EV motor axles wont turn again until the pyrofuse is replaced.
I think the earlier example that required a full recovery truck - that sounds exactly like a blown pyrofuse, which is by far the most common reason an EV ends up requiring a full lift/dollies rather than a simple tow on its own axles.
This is also why you generally always smell burning in the cabin after a tesla shunt too - nothing to do with a battery fire, its the smell of the pyrofuse burning out under the rear passenger seat.
> https://www.wired.com/story/evs-fire-pyroswitches-cut-risk-shock-crash/ https://www.wired.com/story/evs-fire-pyroswitches-cut-risk-s...
- dinom 3y ago> You can enable free-roling wheels in the car and push away This was mentioned a little earlier and further down in the comment tree but many thanks to you too for clearing this up.
- Reubachi 3y agoI'm racking my brain on this. Why is this not just called exactly what it is, "Neutral"? I just read about this feature which is advertised purely for car washes, and can be gotten into with a wierd combination of actions or "putting the car into neutral". Is it...not just going into neutral via disconecting a drive shaft?
- giobox 3y ago> 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 service items on most EV drivetrains until a quick coolant flush in ~10th year of car's life span). The Model 3/Y just dump the output of the rotor into a permanently locked 9:1 trans. There is no need for a reverse gear either as unlike a gas engine the electric motor can easily rotate in both directions. An electric motor cant "stall" like a gas engine and generally never has to change gear, so there is usually no real benefit to fitting the cost and complexity of clutching driveshafts you typically need when you have a gearbox or gas engine. Someone will correct me if I'm wrong, but to best of my memory the only "mainstream" EV with a gearbox on sale today is the Porche Taycan/Audi E-Tron GT (they are both the same chasis/drivetrain underneath) with its pretty unusual 2-speed setup. I wouldn't be surprised at all if the next generation of that car eliminates the gearbox.
- colejohnson66 3y agoIf 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?
- anticensor 3y agoIt disconnects the excitation current.
- dinom 3y ago> Is it...not just going into neutral via disconecting a drive shaft? Very good point and although IDK how it's done I completely agree with you regarding the terminology. In other words, I don't see new internal combustion cars renaming neutral to be "car wash mode"... lol. Cars should have neutral. And, if yours does then it should be named as such. Making sure I've got "car was mode" is not what I want to do when I'm in the market for a new car. Nor do I want to start reading through the owners manual should I have to push my car onto the shoulder of the road in an emergency. Perhaps my age and crotchety grumpiness is starting to show.
- pests 3y ago> You can enable free-roling wheels in the car and push away Is that possible when the car is persumed dead? Or why would you be trying to push it otherwise? If you can enable free-rolling wheels, why not just drive away?
- giobox 3y agoRight - pyrofuse blow has prevented this in my experience. That's why I've specifically called out shunts. If there is no impact, you would be pretty unlucky to not be able to do it.