TFL Trucks Independent Towing Test

[turbopilot]

 

[josephpRV]

This is a great test and it lines up with my own (very brief) towing experience. Pulling the Lightship, with its inherent aero advantages and TrekDrive, basically gives you your standard efficiency (maybe down a few negligible percentage points).

As an EV owner, I was selfishly hoping they’d run the test with an EV, but once I saw the results, it became clear that it doesn’t really matter. The relative data translates just fine for my use case.

That said, I would have loved to see a third variation, towing the Lightship without TrekDrive. That would help separate how much of the efficiency gain comes from the aerodynamics versus TrekDrive itself, and add to the growing pool of data.

In the end, I think new owners will calibrate their towing scenarios and develop their own internal benchmarks for range expectations. Still, it would be fantastic if the Lightship team eventually re-ran this test with two identical trucks and two Lightships, one with TrekDrive engaged, one without, to answer that question more conclusively.

 

[turbopilot]

That said, I would have loved to see a third variation, towing the Lightship without TrekDrive. That would help separate how much of the efficiency gain comes from the aerodynamics versus TrekDrive itself, and add to the growing pool of data.

In the end, I think new owners will calibrate their towing scenarios and develop their own internal benchmarks for range expectations. Still, it would be fantastic if the Lightship team eventually re-ran this test with two identical trucks and two Lightships, one with TrekDrive engaged, one without, to answer that question more conclusively.

They have the efficiency data for TrekDrive off. From what I have seen there is an efficiency gain with a 50/50 split aerodynamics/TrekDrive ON compared to pulling a high profile trailer. Same split appears to exist for EV/HEV/ICE vehicles. I confirmed this on my short drive/tow with my F-150 PowerBoost.

I have been talking with Ben for several months about a second TrekDrive mode that does not have a name but it basically is a hybrid mode of TrekDrive ON. The concept of this mode is not to engage TrekDrive running at highway speeds, then turn it on automatically with higher demand, such as high winds or going up hill. For HEV/ICE trucks this will significantly improve efficiency because higher demand typically kicks in boost from turbochargers that really increases the fuel flow significantly. So basically you use the LightShip battery when the tow vehicle is making power inefficiently. Not sure how this mode would impact EV efficiency, but it would improve it.

Bottom line, this hybrid mode would most likely settle out some where between 50% and 100% return of non-towing efficiency for the tow vehicle while preserving some LightShip battery SOC for the destination. This is just a discussion right now so we won't see it soon. It can all be done via a firmware update if it happens.

The other feature I have been talking to Ben about is in-motion charging of the LightShip from a tow vehicle (EV/HEV) equipped with an in bed inverter/generator. When I was at the factory in April we confirmed the LightShip will charge from the PowerBoost 7.2 kWh inverter/generator using a standard Tesla Level 2 portable charger into the NACS connector plugged into the bed connector of the PowerBoost. This will allow the conversion of regenerative energy from the PowerBoost and/or the engine driving the traction motor making electricity in the PowerBoost to supply up to 7.2 kWh of power to the LightShip in motion.

LightShip TrekDrive nominally requires about 250 watts/mile, so at 60 MPH the LightShip would pull about 15 kW from the battery every hour. With in motion charging from a tow vehicle bed mounted inverter/generator you could transfer about 50% of the TrekDrive demand from the tow vehicle back to the LightShip.

One detail to be worked out for this idea is that currently when TrekDrive is ON, it locks out the NACS port. Ben says this is a firmware constraint that might be able to be changed.

 

[josephpRV]

They have the efficiency data for TrekDrive off. From what I have seen there is an efficiency gain with a 50/50 split aerodynamics/TrekDrive ON compared to pulling a high profile trailer. Same split appears to exist for EV/HEV/ICE vehicles. I confirmed this on my short drive/tow with my F-150 PowerBoost.

I have been talking with Ben for several months about a second TrekDrive mode that does not have a name but it basically is a hybrid mode of TrekDrive ON. The concept of this mode is not to engage TrekDrive running at highway speeds, then turn it on automatically with higher demand, such as high winds or going up hill. For HEV/ICE trucks this will significantly improve efficiency because higher demand typically kicks in boost from turbochargers that really increases the fuel flow significantly. So basically you use the LightShip battery when the tow vehicle is making power inefficiently. Not sure how this mode would impact EV efficiency, but it would improve it.

Bottom line, this hybrid mode would most likely settle out some where between 50% and 100% return of non-towing efficiency for the tow vehicle while preserving some LightShip battery SOC for the destination. This is just a discussion right now so we won't see it soon. It can all be done via a firmware update if it happens.

The other feature I have been talking to Ben about is in-motion charging of the LightShip from a tow vehicle (EV/HEV) equipped with an in bed inverter/generator. When I was at the factory in April we confirmed the LightShip will charge from the PowerBoost 7.2 kWh inverter/generator using a standard Tesla Level 2 portable charger into the NACS connector plugged into the bed connector of the PowerBoost. This will allow the conversion of regenerative energy from the PowerBoost and/or the engine driving the traction motor making electricity in the PowerBoost to supply up to 7.2 kWh of power to the LightShip in motion.

LightShip TrekDrive nominally requires about 250 watts/mile, so at 60 MPH the LightShip would pull about 15 kW from the battery every hour. With in motion charging from a tow vehicle bed mounted inverter/generator you could transfer about 50% of the TrekDrive demand from the tow vehicle back to the LightShip.

One detail to be worked out for this idea is that currently when TrekDrive is ON, it locks out the NACS port. Ben says this is a firmware constraint that might be able to be changed.

Now that you mention it, I think I heard anecdotally about the 50/50. Would love to see empirical data. Since I'll be towing with an EV there'll be points where decoupling to charge my Rivian and the Lightship will be impractical, so I'd like to understand the efficiency dynamics separately, but that's a tomorrow issue.

 

[turbopilot]

Now that you mention it, I think I heard anecdotally about the 50/50. Would love to see empirical data. Since I'll be towing with an EV there'll be points where decoupling to charge my Rivian and the Lightship will be impractical, so I'd like to understand the efficiency dynamics separately, but that's a tomorrow issue.

For the Rivian it is easy to back into the answer of pulling the LightShip without TrekDrive active. Rolling down the highway at 62 MPH the LightShip consistently uses 250 watts/mile to operate TrekDrive. So using the numbers in the LightShip video below (where they were towing with the Rivian) you simply add 250 watts/mile to the Rivian consumption illustrated on the table in the video.

In essence as the Rivian is rolling down the highway it is in a 3 electric motor drive axle configuration as a unit. If you turn off power to one drive axle the other two pick up the load of 250 watts/mile.

 

[Holdmybeer]

The 44 kWh battery in trek drive mode will last a little better than 2 hrs.. on flat terrain. Square the rest of that circle.

 

[turbopilot]

The 44 kWh battery in trek drive mode will last a little better than 2 hrs.. on flat terrain. Square the rest of that circle.

The 44 kWh battery is only available in the Panos. It was a model targeted to those sensitive to the cost but more importantly it is direct competition for the Pebble Flow towable that also has a 44 kWh battery. It would have more utility for those making shorter trips. May be a good fit for those in the Eastern US who typically travel shorter distance to camp.

But putting TrekDrive aside, at 44 kWh the Panos battery is still 15 times the capacity of a similar size and priced Airstream trailer.

 

[Holdmybeer]

The 44 kWh battery is only available in the Panos. It was a model targeted to those sensitive to the cost but more importantly it is direct competition for the Pebble Flow towable that also has a 44 kWh battery. It would have more utility for those making shorter trips. May be a good fit for those in the Eastern US who typically travel shorter distance to camp.

But putting TrekDrive aside at 44 kWh the Panos battery is still 15 times the capacity of a similar size and priced Airstream trailer.

You're comparing apples to oranges. An Airstream which has a 7 decade claim to fame makes no claims to be a fully self contained travel trailer. While otherwise it doesn't matter how big the battery is if it's fully depleted when you arrive at the destination with no means other than solar for recharging. Doesn't matter how great your gas mileage was getting there if you're dead in the water on arrival. Gemini AI tells me that it would take 8.5 days for the solar array on a lightship to recharge a fully depleted 77 kWh battery ( The 77 kWh battery would fully deplete in 3.85 hrs. of trek drive use). That's 8.5 days of not using the battery.