Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Tow Mode

This site may earn commission on affiliate links.

vfx

Well-Known Member
Aug 18, 2006
14,790
52
CA CA
Talk of a driver needed to be towed because of running a car out of charge.

In order to tow the Roadster the VDS screen can help the driver release the paw that locks the transmission to allow the car to run safely and freely.

If a driver were to run his or her battery totally empty then how would there be enough energy to move the paw? Presumably on an electrically powered solenoid of some sort.

For that matter would the VDS even work?
 
Last edited:
If it is like my RangerEV, the computer will lock out driving functions before the pack is so run down that it can't provide 12V anymore. You can probably run the VDS for quite a while after the car refuses to let you drive it.
I think it would be unheard of for the batteries to go completely 'dead'. The computer has to stop letting you drive when it knows that pack is so low that further driving will damage the batteries.

I know when you get stuck at the side of the road you might wish you got that extra mile or two of range, but would it be worth a $15,000+ battery pack just to avoid walking a little?

If you managed to let the pack get so low that it can't even power up the VDS then I wonder if you could recharge it at all. It might have to go back to 'home base' for some sort of 'pack bootstrap' procedure.

I think if it runs down to the point of refusing to drive, it would probably be a good idea to start charging it (via tow regen, or on charger) ASAP.

(BTW, Tow regen was something I asked about on the TMC blog in the early days... I wonder if I had anything to do with them offering it).
 
Last edited:
If a driver were to run his or her battery totally empty
Engineers were smart enough to program the computer to stop at 20% SOC in Normal mode or around 10% in Range mode. Of course, the label will say Empty but there will be about 5kWh left in there.

If you than leave the car for couple of years standing in the sun it wil discharge to empty and battery will die.
 
I was under the impression that out of the ESS's 11 "sheets" of cells that 10 of them provided motive power, and that 1 was dedicated to providing power for the other systems on the car (such as heating/AC, audio, lights, VDS, etc.). Did this change? Am I remembering this information incorrectly? Did I dream it? :confused:

btw vfx, congrats on getting your Roadster... :biggrin:
 
Last edited:
I was under the impression that out of the ESS's 11 "sheets" of cells that 10 of them provided motive power, and that 1 was dedicated to providing power for the other systems on the car (such as heating/AC, audio, lights, VDS, etc.). Did this change? Am I remembering this information incorrectly? Did I dream it? :confused:

There have been a couple of discussions about that.
I always assumed it was a DC/DC converter stepping down the full pack voltage, but I don't think we ever got a clear answer either way.

There was some discussion here
 
What's tow regen? Is it where the batteries are charged by the rotating wheels as the car is being dragged?

Yeah, that was the basic idea. The idea I had in mind was for RV drivers pulling their Roadster behind their RV on a long trip. It seems using Regen between stops could allow you to always have a full Roadster when you stop somewhere.
 
Towing the Roadster does work. That's what the Ferdinand Motors team did with their Roadster on the EVS race. The last day they were down to about 20% charge and had a whole day of driving left. So they got a towtruck to tow it for about 1-2 hours that night and that got it back to about 70-80% charge...

Cobos
 
I don't see how or why "tow charging" via regen wouldn't work.

Except for inclination sensors saying to computer "we cannot possibly be regenerating for front is way higher than back". It should also charge the battery faster than even HPC. Regen goes above 30kW as new power gauge is labled to 40kW. Towtruck will burn quite some more fuel though.
 
Towing the Roadster does work. That's what the Ferdinand Motors team did with their Roadster on the EVS race. The last day they were down to about 20% charge and had a whole day of driving left. So they got a towtruck to tow it for about 1-2 hours that night and that got it back to about 70-80% charge...

Cobos

haha was that even allowed?
 
I don't see how or why "tow charging" via regen wouldn't work.

If you left the key in the ignition with everything on, and you used a tow bar with all 4 Roadster wheels on the ground then yeah, it probably couldn't tell the difference from rolling down a hill. But there might be some optimizations you could make if you were going to create a real "car being towed" mode. Some things might be:

#1: Lock out the accelerator pedal so if someone jumped in and tried to drive nothing would happen.
#2: Allow the key to be removed and the steering column locked. (If you park no one can reach in and grab the keys).
#3: Make the brake lights activate only when the VDS notices that the vehicle is slowing down. (If regen normally triggers the brake lights, you don't want it to constantly show brake lights when the tow vehicle is maintaining speed).
#4: (Perhaps not possible). Detect if going uphill, and stop doing regen so that the tow vehicle doesn't have to work as hard during times when it needs full power.
#5: Don't do any regen at speeds below 30MPH. The tow vehicle may need power for getting on an onramp, or stop and go city traffic, so tow regen is probably only appropriate when cruising on a highway.
...just some ideas...
 
Owners manual Warranty Guide page 4.

What is not covered

General exclusions

The New Vehicle Warranty does not cover damage caused by:

* [accidents]
* [car washes]
* Towing the vehicle instead of transporting the vehicle on a flat bed
* [theft]
* [explosions]
*
*
*
*
*
*
*
*
 
Last edited:
What about involuntary towing?

If a Tesla Roadster were parked illegally and was towed away without being set to tow mode on the VDS, would this damage the Tesla Roadster?

Towing companies typically are liable for damage they cause during towing. The courts have ruled on this issue consistently to the point that it is accepted as common law by insurance companies.