Flat towing the Cybertruck, "It's a giant battery for my RV", etc

[scottf200]

“Not only can a Tesla not be flat-towed, it must be towed on a trailer, not a dolly with two wheels on the ground. According to the manufacturer, towing it any way except on a trailer will void the warranty, to say nothing of damaging the car.”

https://www.rv.com/archive/rv-tech-qa-august-2019/

So what do you guys think about Rivian just having anounced that the dual motor will be flat towable? (conversation with Munro and RJ Scaringe)

That Rivian interview/conversation was great.
It sounds like they went the extra mile to make sure the Rivian could be towed without any problems (disengaging internal techniques). EVs are perfect vehicles at a campground with power outlets as needed for charging too.

Sponsored

 

[JBee]

I haven't watched the interview, anyone have a link handy?

If the Rivian has a clutch to disengage the motors that will make flat towing efficient and easy to do.

With a Tesla, where they can't disengage the drivetrain with a clutch, as they don't have them, but they could implement some sort of battery management software that allows the Tesla to assist when travelling and accelerating, and decelerate with regen so that the battery stays within specification. That would mean that it would "hyridise" the tow vehicle, by reducing fuel consumption on climbs and also reduce brake wear on the tow vehicle by using regen. Essentially, it is a "reverse" trailer, in that the trailer is in front, but otherwise much the same. It would increase the range of the tow vehicle, and could even be used to charge the Tesla by the time you get to the destination.

There is no reason for the towed Tesla to always be on full regen, you can just modulate that with an existing brake controller connection, or at a minimum even through CV in that the Tesla will see the brake lights go on. It would be better to have granular brake control through a controller though.

Technically, that is just a software update away for all Teslas if they so choose to do so, you could then even add a destination to the Tesla via the app, and say what level of charge you would like to have when you get there.

 

[Cyberman]

Thank you for that.. That was my best recollection and thus the still outstanding question.

Warranty concerns aside (which they will never be).. Wouldn't it be the case that if one towed a cybertruck, say with a hypothetical operator behind the wheel, wouldn't that be seen by the truck as regenerative braking, thus charging the batteries?

Could be. But it's gonna feel like you're towing an Abrams tank.

 

[Cyberman]

I haven't watched the interview, anyone have a link handy?

If the Rivian has a clutch to disengage the motors that will make flat towing efficient and easy to do.

With a Tesla, where they can't disengage the drivetrain with a clutch, as they don't have them, but they could implement some sort of battery management software that allows the Tesla to assist when travelling and accelerating, and decelerate with regen so that the battery stays within specification. That would mean that it would "hyridise" the tow vehicle, by reducing fuel consumption on climbs and also reduce brake wear on the tow vehicle by using regen. Essentially, it is a "reverse" trailer, in that the trailer is in front, but otherwise much the same. It would increase the range of the tow vehicle, and could even be used to charge the Tesla by the time you get to the destination.

There is no reason for the towed Tesla to always be on full regen, you can just modulate that with an existing brake controller connection, or at a minimum even through CV in that the Tesla will see the brake lights go on. It would be better to have granular brake control through a controller though.

Technically, that is just a software update away for all Teslas if they so choose to do so, you could then even add a destination to the Tesla via the app, and say what level of charge you would like to have when you get there.

Sounds amazing. I'd love it if it's possible

 

[scottf200]

I haven't watched the interview, anyone have a link handy?

If the Rivian has a clutch to disengage the motors that will make flat towing efficient and easy to do.

Yes, I do. I just went to my YT history and search on RJ. I watched/listened at x1.75 speed.

13:25 minutes in.

 

[JBee]

Yes, I do. I just went to my YT history and search on RJ. I watched/listened at x1.75 speed.

13:25 minutes in.

Thanks
I'll check it out tonight.

 

[AustroTom]

Sorry, wanted to add a link but scott was so kind in doing so before me.
So how can we get Tesla to adopt this feature?

 

[CYBRSMTH]

Greetings,

With a 9kW ground mount solar array going up adjacent to my new RV cover so time to ask:

1) Any idea if I can 'flat tow" (ie, w/o trailer) a Cybertruck?

2) The flat tow question relates to possibly getting a motorhome with a diesel genset (always handy) with a separate fuel tank that I could fill w/ off road if needed for SHTF, as above.

3) Already had an electrician go over my RV bumper pull and easy to run a circuit to not even have to unhook camper, but plug into 50A at campground and charge CT when trailer is plugged in. A state park campground will cost about $12-20 for 50A and, if my math doesn't suck (it does) would yield about $33 worth of electricity at $0.133/kWh

4) Great appeal of CT is that with 200 kW of battery, if truck were charged I'd be good to go off grid for a while if SHTF and that battery capacity, if installed into the RV, (forget the weight) would be about $40k USD by itself. (See above math disclaimer)

PV array is like this but two panels wider, 28 in all.

Any and all thoughts most welcome, as always

JR

As a general rule flat towing any EV is not recommended.

 

[AustroTom]

Granted, but this is not about a general rule. This is about creating a vehicle that is near darn perfect

 

[JBee]

Sorry, wanted to add a link but scott was so kind in doing so before me.
So how can we get Tesla to adopt this feature?

It would be nice if there was a way to recommend features or designs to the CT or Teslas in general. But I'd expect they'd be inundated with ideas, of which probably 99% won't work, cost to much to accommodate, or simply not many people would want to have on their vehicle. You'd need a whole team just to process the recommendations, and even then it's unlikely you'd get a meaningful result out of all those requests.

So hopefully they are thinking about a way to make this work, given that Rivian seems to be giving them some incentive to do so. But, it's also quite possible that Tesla doen't want to add such a feature for safety reasons, or potential public relation issues if it goes wrong. I'm not sure the risk/reward is in Teslas favour for this feature, so it's quite possible they won't ever implement it. At a minimum demand would have to be high enough for the feature to make it worth it.

 

[CyberGus]

Once FSD is shipped, the truck can just follow you everywhere

 

[Rutrow]

With a Tesla, where they can't disengage the drivetrain with a clutch, as they don't have them,

The Tesla Semi has a clutch that disengages two of the three motors to save energy when max torque isn't needed.

They have it, so they could disengage all the motors if they wanted to compete for the lucrative High Dollar Class A Motorhome segment who love flat towing large vehicles behind.

 

[JBee]

The Tesla Semi has a clutch that disengages two of the three motors to save energy when max torque isn't needed.

They have it, so they could disengage all the motors if they wanted to compete for the lucrative High Dollar Class A Motorhome segment who love flat towing large vehicles behind.

Semi has a clutch, but none of the current Teslas do, and as far as we know CT doesn't either.

If they go the smaller QM as standard accross the range route, hence also the new gen sub $600 motor drivetrain that has no rare earth metals. Which would mean they seem to be switching to induction motors again, where they simply won't need them anyway on the CT. Induction motors can free-wheel with minimal loses as you can turn off the magnetic feild, which you can't do with a PM as well.

 

[HaulingAss]

The why not is complex and yet simple. Simple, because it's an edge case use and Tesla is very slow to respond to those. Complex, in that you'd need some way to divert the power from the spinning motors so the battery doesn't overcharge or be too much rolling resistance. As well as to alert the driver of the towing vehicle of the towed vehicle's status.

-Crissa

Where does the electricity from the spinning motors go when I lose regen capability either because the battery is too cold to charge or because it's already at or near 100% SoC?

In other words, it would seem Tesla, and every other EV maker, has already solved this. The motors are spinning when descending a grade or slowing down, but the batteries are not soaking up the energy generated.

 

[Crissa]

Where does the electricity from the spinning motors go when I lose regen capability either because the battery is too cold to charge or because it's already at or near 100% SoC?

I don't know, I just know they don't want to do it for long.

There's ways to create dummy loads, shorts, electrical disconnects, and, like on the Semi, an actual clutch. So there's ways to do it. Dummy loads and shorts still create heat and potential, and while you as a driver would be aware if something went wrong in the drive system, someone towing wouldn't.

-Crissa

Sponsored