PowerBoost "Free" Electricity to an Airstream Globetrotter

[turbopilot]

I just completed a 1,500 mile trip pulling an Airstream Globetrotter with my F-150 PowerBoost with ProPower on Board. The trip was mostly in temperatures up to 103F over the trip in this recent heat wave.

While in motion the F-150 PowerBoost was supplying around 2.3 kW of electricity to the Globetrotter mostly to run the aft 15,000 btu air conditioner. In motion with only the rear air conditioner running the Globetrotter internal temperature never exceeded the set point of 80F. Keeping the Globetrotter cabin at 80F also allowed the refrigerator to maintain normal temperatures during the trip.

But the most interesting finding is that there does not appear to be any impact on the fuel economy of F-150 generating 2.3 kW while in motion. This is counter intuitive. There has to be a reason why I am getting this free electricity with no penalty to fuel efficiency of the truck.

It appears this gift comes from the unique interaction of the F-150 PowerBoost towing this heavy trailer and generating more electricity than the high voltage battery can store when the traction motor is running in regeneration mode. Ford limits the SOC high set point of the high voltage battery to preserve battery life. So when the F-150 is generating electricity going down hill or braking, once the battery hits the high limit, the PowerBoost uses only engine braking and friction brakes to control speed rather than regenerating electricity from the traction motor between the engine and the transmission.

But ProPower on Board is also harvesting that excess electrical energy via the PPoB inverter to make up to 7.2 kW of AC power that is now available to the Globetrotter. Apparently this is electricity that would have gone to waste once the high voltage battery is full.

Very complicated but it shows how versatile the hybrid trucks can be. Here is a screen shot from the OBDLink app showing the power being generated by the PPoB generator in the PowerBoost while in motion.

Sponsored

 

[nickn066]

Another way to look at it, is in motor effort, 7.2kw is ~10hp. Even if the traction motor was incredibly inefficient at converting gas to electric , it would still only be 15-20hp being robbed from the engine and only when it’s at the full 7.2kw. Not including all the energy regen the truck does like you mentioned.

 

[turbopilot]

Another way to look at it, is in motor effort, 7.2kw is ~10hp. Even if the traction motor was incredibly inefficient at converting gas to electric , it would still only be 15-20hp being robbed from the engine and only when it’s at the full 7.2kw. Not including all the energy regen the truck does like you mentioned.

True but I wonder if anything is being "robbed" from the output to the wheels. My PowerBoost and Airstream is rolling along weighing 14,600 lbs. That is a lot of mass in motion. That traction motor is constantly cycling between using electricity and making electricity even in totally flat stretches of road. All I can see is the net I/O going in and out of the high voltage battery with OBDLink app. Meanwhile the AC/DC inverter, DC/DC inverter and cooling pumps are all using electricity on the high voltage bus. There is no indication that the traction motor in generator mode is ever robbed of electricity since the battery is generally no lower than 35%. The logic is telling the traction motor when to make electricity versus use electricity. So I wonder if the electricity going to DC/AC inverter is just consider surplus to the trucks need.

Looking at it another way when I am rolling down the highway with the trailer in tow I normally see fuel flows of 3 to 3.5 gallons/hour. We know PPoB burns around 1 gallon per hour when operating at full output generating electricity standing still. So if fuel is being used to generate electricity in motion, it should show up in the fuel flow and MPG calculations. But it is not. I am not seeing a difference in fuel flow when PPoB is operating in motion. Of course very few people are using the electricity generated from PPoB in motion so my use case is quite unusual.

Not many things are free but in this case it maybe because the PowerBoost may not be set up to use all the electricity it can generate when pulling a big load.

 

[nickn066]

True but I wonder if anything is being "robbed" from the output to the wheels. My PowerBoost and Airstream is rolling along weighing 14,600 lbs. That is a lot of mass in motion. That traction motor is constantly cycling between using electricity and making electricity even in totally flat stretches of road. All I can see is the net I/O going in and out of the high voltage battery with OBDLink app. Meanwhile the AC/DC inverter, DC/DC inverter and cooling pumps are all using electricity on the high voltage bus. There is no indication that the traction motor in generator mode is ever robbed of electricity since the battery is generally no lower than 35%. The logic is telling the traction motor when to make electricity versus use electricity. So I wonder if the electricity going to DC/AC inverter is just consider surplus to the trucks need.

Looking at it another way when I am rolling down the highway with the trailer in tow I normally see fuel flows of 3 to 3.5 gallons/hour. We know PPoB burns around 1 gallon per hour when operating at full output generating electricity standing still. So if fuel is being used to generate electricity in motion, it should show up in the fuel flow and MPG calculations. But it is not. I am not seeing a difference in fuel flow when PPoB is operating in motion. Of course very few people are using the electricity generated from PPoB in motion so my use case is quite unusual.

Not many things are free but in this case it maybe because the PowerBoost may not be set up to use all the electricity it can generate when pulling a big load.

That's kind of what I mean. After you've accelerated the truck to cruising speed, it takes very little power to keep it moving, and having that extra 15hp load on the truck while accelerating is nothing compared to the power required to get it up to speed, so I doubt you'd see that in your fuel economy.

As an extra data point, I went with one of my friends on a 6 hour journey to pick up a used Fiat 500e. It didn't even have enough power to drive into the box trailer, but we plugged it in on the drive home, was using about 6.5kw for 3 hours and my fuel economy was .2 MPG less than the drive to get it on pretty flat roads running 70. Got to my house with plenty of power for him to drive it home.

 

[moritzes]

Nice. You'd be interested to know that there's a guy over at the Airstream forum who took a very similar trip recently...

 

[turbopilot]

You'd be interested to know that there's a guy over at the Airstream forum who took a very similar trip recently...

Yes, there are a few over there including me who are using PPoB in motion, so just trying to find out their experience.

 

[turbopilot]

As an extra data point, I went with one of my friends on a 6 hour journey to pick up a used Fiat 500e. It didn't even have enough power to drive into the box trailer, but we plugged it in on the drive home, was using about 6.5kw for 3 hours and my fuel economy was .2 MPG less than the drive to get it on pretty flat roads running 70. Got to my house with plenty of power for him to drive it home.

Thanks for that datapoint. Given such a low fuel flow to generate 6.5 kW it sort of proves my point since one gallon of gas after conversion losses can only make about 10 kW of electricity. In your example fuel flow per hour should have increased at least .6 gph.

Whatever is going on with PPoB in motion, it is delivering electricity much more efficiently than just burning gas to get the equivalent kW content.

 

[Hans Moleman]

HV battery temp 118*F

I guess I shouldn’t feel so bad whenever my HV battery reaches 120*F

 

[turbopilot]

HV battery temp 118*F

I guess I shouldn’t feel so bad whenever my HV battery reaches 120*F

Yes, but note the OAT (Outside Air Temp) is 97F, so a pretty common temperature when it is hot outside.

 

[Kodiak]

Outstanding incite and post @turbopilot ! This truck really is a marvel.

It is a pity that Ram made a business decision to bump the Ramcharger production in favor of the Hemi. They are not doing the Ramcharger any favors. I think this release could get Ford motivated to move a little faster on the PB Superduty, but alas we wait.

 

[turbopilot]

Outstanding incite and post @turbopilot ! This truck really is a marvel.

It is a pity that Ram made a business decision to bump the Ramcharger production in favor of the Hemi. They are not doing the Ramcharger any favors. I think this release could get Ford motivated to move a little faster on the PB Superduty, but alas we wait.

Yes, but I would sure like to know what is going on with the PB. Getting energy for free is too good to be true, unless this is just a delightful result of Ford using a battery that is too small.

 

[Brazos Drifter]

Yes, there are a few over there including me who are using PPoB in motion, so just trying to find out their experience.

We have a 21 Powerboost 7.2 kw and an Airstream 28 classic. Can someone please point me to how to make the 220v connection to the trailers while towing?

 

[v8440]

To make the 2.3 kW you reported your trailer was actually using during the trip would take under 5 hp of mechanical power. You probably wouldn't notice that anyway, or only barely, even without the hybrid goings-on you mentioned. That's what I think it is-simply, that 2.3 kW is washed out in the overall picture of the power it takes to keep the truck and trailer moving at highway speeds.

 

[turbopilot]

We have a 21 Powerboost 7.2 kw and an Airstream 28 classic. Can someone please point me to how to make the 220v connection to the trailers while towing?

I detailed my umbilical hookup between the Airstream and the PowerBoost in this long thread over on the Airstream forum. Let me know if you have any questions either here or on the Airstream forum.

https://www.airforums.com/forums/f37/electric-globetrotter-229144.html#post2552311

 

[Brazos Drifter]

I detailed my umbilical hookup between the Airstream and the PowerBoost in this long thread over on the Airstream forum. Let me know if you have any questions either here or on the Airstream forum.

https://www.airforums.com/forums/f37/electric-globetrotter-229144.html#post2552311

Wow! Your work is impressive. I am afraid I am not up to tackling that complexity. I may be naive, but I thought I could just rig a short connection from myPPoB outlet to the maybe a receptacle on the front of the trailer so I could run an A/C while traveling or a short Walmart overnighter/dispersed camping in-between full hookup campgrounds. I did not see the umbilical set up. Sure would appreciate your advice.

Sponsored