Is there anything SM could offer to get you to switch from EREV to BEV?

[R1TVT]

I wonder what performance implications will be when temps are high. Given that cooling will be important, and given the space constraints - towing in the midday heat of summer will likely be more challenging than towing at night or in winter (I would think)?

 

[SpaceEVDriver]

I wonder what performance implications will be when temps are high. Given that cooling will be important, and given the space constraints - towing in the midday heat of summer will likely be more challenging than towing at night or in winter (I would think)?

Yes. The SAE standard requires the tests at the Davis Dam be run with at least 100 ⁰F (38 ⁰C) ambient temperature. The basic radiative cooling equation is dependent on (T-Ta)^4.

For the sake of argument, say the coolant temperature is 50 ⁰C. Compare 100 ⁰F (38 ⁰C) with 50 ⁰F (10 ⁰C) ambient temperatures:

At 38 ⁰C, the radiative portion of the cooling equation has a T^4 value of (50-38)^4 = 20,736.

At 50 ⁰F (10 ⁰C), the value is, (50-10)^4=2,560,000.

There are a bunch of other factors that make this not quite so dramatic as it looks, but it's still a big consideration.

 

[04Ram2500Hemi]

All any of us can really do is I see a lot of posts on Facebook and it’s a lot of complaining about range or asking for under $40K. Certainly hope it’s a success. Been wanting another Scout for over 35 years

I personally believe that Scout will succeed and produce quality vehicles.

 

[SrfnFly227]

I have a feeling that when the specs do come out a lot of the Harvester reservations will either change to bev or go away. I hope not but so many folks on this forum and FB are expecting way to much from the Harvester. They just hear gas and go and 500 mile range and they want that.

The 500 mile range is also probably a one time thing. As in you leave your house with a full battery and a full tank of gas. The Harvester will supplement the battery and you'll drive 500 miles and finish with no battery charge and an empty tank of gas. Filling the tank isn't going to get you another 500 miles. I'd be willing to bet it won't even get you another 350 miles.

Assumptions with made up numbers:
- Max Range of 500 miles will have the Harvester run at 1500 RPM to maximize efficiency and you'll still see the battery drain while driving.
- Full tank of gas, but zero battery charge will require more power from engine and it will run at 3000 RPM in order to produce what's required without the ability to use battery. 250-300 miles driving rather than the 350 people envision.

 

[J Alynn]

The 500 mile range is also probably a one time thing. As in you leave your house with a full battery and a full tank of gas. The Harvester will supplement the battery and you'll drive 500 miles and finish with no battery charge and an empty tank of gas. Filling the tank isn't going to get you another 500 miles. I'd be willing to bet it won't even get you another 350 miles.

Assumptions with made up numbers:
- Max Range of 500 miles will have the Harvester run at 1500 RPM to maximize efficiency and you'll still see the battery drain while driving.
- Full tank of gas, but zero battery charge will require more power from engine and it will run at 3000 RPM in order to produce what's required without the ability to use battery. 250-300 miles driving rather than the 350 people envision.

Dumb question but as a generator, are others expecting multiple RPM’s or more likely a constant RPM since it is only charging and not driving the wheels?

 

[maynard]

Dumb question but as a generator, are others expecting multiple RPM’s or more likely a constant RPM since it is only charging and not driving the wheels?

I was expecting one or maybe two rpm levels (regular and higher output)…

 

[Hedges1]

Dumb question but as a generator, are others expecting multiple RPM’s or more likely a constant RPM since it is only charging and not driving the wheels?

@Jamie@ScoutMotors believe you indicated a handful of operating profiles for the generator in our interview, but not a ton of variability

 

[chucchinchilla]

I was expecting one or maybe two rpm levels (regular and higher output)…

Based on the videos/interviews I've seen, it's not RPM levels being the variable but instead battery level (say keep it at 80%). Outside of that you can of course choose to keep it on full time or off full time.

 

[speedrye]

Hopefully the generator will be a starter/generator so no additional starter is needed, but that would require the main battery to have juice to start the engine. Throw me a crank handle in the jack kit since I wouldn't be able to jump start it.

 

[6-ScoutFamily]

Hopefully the generator will be a starter/generator so no additional starter is needed, but that would require the main battery to have juice to start the engine. Throw me a crank handle in the jack kit since I wouldn't be able to jump start it.

Lemme alone, lemme alone, lemme alone
Lemme alone, lemme alone, lemme alone
Lemme alone, lemme alo…

ALLLLRIIIIIIGHHHHTTTTT!

 

[maynard]

Lemme alone, lemme alone, lemme alone
Lemme alone, lemme alone, lemme alone
Lemme alone, lemme alo…

ALLLLRIIIIIIGHHHHTTTTT!

That’s what my previous boat sounded like when starting…

 

[Jasco]

I'm pleasantly surprised by the math for the "built rig" scenario though I remain a tad skeptical on the performance front especailly if the RPM is capped on the engine for efficiency/longevity reasons. They put big engines in big vehicles for a reason. That said, a turbo would make a difference here as would a 2L engine versus the 1.4 I thought was annnounced. On the other hand, I'm not convinced that towing will be a carefree experience given the numbers @SpaceEVDriver presented. A 100 degrees hill climb is not a torture test. It is simply summer in the western United States. Refueling distance is less of a concern for me. 200 miles of gas only range would be more than enough for most people and the engine would likely get 250 miles of range or more. Just a guess. The original Scout II had a range of 266 miles (400 with a couple of Jerry cans ). Cooling is a concern of mine though. I know nothing of automotive engineering so please enlighten me, but I would think placing an engine under the vehicle without direct frontal airflow has its challenges. Pulling air from underneath would increase drag as would getting it from air rediected from the sides of the vehicle. I trust that the Scout engineers will work this out but it is a huge challenge in my mind. Cooling both the engine and the rear motor in close proximity to each other would also appear to be a challenge. I appreciate the community's insights as I try to learn more about this technology. The more I learn, the better informed I will be when my reservation comes up.

 

[SpaceEVDriver]

IMO, the proper way to cool a mid- or rear-mounted engine is not through airflow directed to the location of the engine. The proper way would be to have a heat pump with an air exchange unit (radiator) at the front of the vehicle as is the norm and run the (insulated) liquid heat transfer lines to the Harvester, just like they do for the battery and the electric motors. Instead of moving air, they should move the thermal management liquid. It’s much easier to contain, it’s a well-understood problem, and it’s already being implemented for thermal management of the battery and motors. The biggest issue this creates is how to easily drop the Harvester if it’s necessary. With the proper kind of flexible lines, this isn’t a huge issue. They can use quick disconnects like they do for hydraulic implements on tractors. But it would mean they would require non-toxic thermal management liquids. Or, if they feel they need more toxic fluids, they can set it up with a vacuum-capable reservoir like a mini-split has so the maintenance tech can pull a vacuum, evacuate all of the liquid into the reservoir and then disconnect the lines. Essentially what they would be installing IS a mini split.

 

[6-ScoutFamily]

That’s what my previous boat sounded like when starting…

My 4 cylinder Scout was kind of like that too.

 

[BeerParty]

<snip>

If the EREV gets 7500 pound towing instead, and has a 7000 pound Gross weight, that brings the GCWR down to 14,500 pounds. That requires a power output of approximately 120 kW, or 160 HP. That’s achievable with some tweaks to the existing EA211 engine. Again, the existing engine will not be a drop-in to the system, it’ll require significant modifications.

After doing the math, I think I have to adjust my guess as to what the EREV tow rating will be. I’m guessing it’ll be around 7500-8500 pounds. This will also account for the higher thermal load the EREV will be producing.

I hope for everyone's sake they don't try and put a 160HP engine in the Harvester. The engine should be sized to provide the average energy needed when towing a trailer on flat ground at highway speeds. Anything more than that is wasted space and weight.

Scout has already mentioned multiple modes for the EREV, and only one of the modes would run the battery all the way down: the BEV mode. I doubt that the truck will allow you to run that mode when towing. In fact, I expect that they will have a towing mode that switches on automatically when towing a trailer. It will likely be designed to work very similar to what the Dodge Ram REV will do when towing - it will run the gen-set to keep the battery above 50%. That way, there is always plenty of power available when extra power is needed for acceleration or going up hills. The battery provides the power needed to go up hills when fully loaded, the gen-set just replenishes the power when the battery gets low (during and after the hill climb).

In a proper setup, the truck will run out of gas before it gets low on battery.

Think about how likely it is to happen. Maybe 1% of the people will have a fully loaded trailer. Maybe 1% of them will try to climb the obnoxious hill with the fully loaded trailer. Running on the battery, those folks will be fine. The situation everyone is afraid of, starting at the bottom of a hill with a trailer and low battery, will only happen if the driver forces it. That is, it will only happen if the driver is trying to fail.

If you size the gen-set for that situation, then it is oversized for the 99% of the people and also 99% of the time for the remaining 1%. Everyone will have to give up the extra space and carry the extra weight of an engine that is overpowered (and less efficient), just to accommodate someone that is deliberately trying to make the truck fail. It isn't just the size of the engine, more power means more cooling and less efficiency. The engine of an ICE truck needs the power and cooling to handle the worst case scenario, and the battery in an EREV needs to do the same. The gen-set in an EREV does not.

 

[Gottesacker]

In a proper setup, the truck will run out of gas before it gets low on battery.

Kind of a separate thought, but this statement made me think. I wonder if we'll be able to drain the tank like you would a regular ICE vehicle, or if they'll have some type of management to keep it from going completely dry.

 

[cyure]

Kind of a separate thought, but this statement made me think. I wonder if we'll be able to drain the tank like you would a regular ICE vehicle, or if they'll have some type of management to keep it from going completely dry.

Oh and this might be a stupid question, but could you drive on battery power with a completely empty gas tank?

 

[R1TVT]

Oh and this might be a stupid question, but could you drive on battery power with a completely empty gas tank?

Yes.

(Gas has nothing to do with powering the motors. Motors are 100% powered by electricity, so the state of the gas tank should not matter to the drive units.)

 

[SpaceEVDriver]

I hope for everyone's sake they don't try and put a 160HP engine in the Harvester. The engine should be sized to provide the average energy needed when towing a trailer on flat ground at highway speeds. Anything more than that is wasted space and weight.

Scout has already mentioned multiple modes for the EREV, and only one of the modes would run the battery all the way down: the BEV mode. I doubt that the truck will allow you to run that mode when towing. In fact, I expect that they will have a towing mode that switches on automatically when towing a trailer. It will likely be designed to work very similar to what the Dodge Ram REV will do when towing - it will run the gen-set to keep the battery above 50%. That way, there is always plenty of power available when extra power is needed for acceleration or going up hills. The battery provides the power needed to go up hills when fully loaded, the gen-set just replenishes the power when the battery gets low (during and after the hill climb).

In a proper setup, the truck will run out of gas before it gets low on battery.

Think about how likely it is to happen. Maybe 1% of the people will have a fully loaded trailer. Maybe 1% of them will try to climb the obnoxious hill with the fully loaded trailer. Running on the battery, those folks will be fine. The situation everyone is afraid of, starting at the bottom of a hill with a trailer and low battery, will only happen if the driver forces it. That is, it will only happen if the driver is trying to fail.

If you size the gen-set for that situation, then it is oversized for the 99% of the people and also 99% of the time for the remaining 1%. Everyone will have to give up the extra space and carry the extra weight of an engine that is overpowered (and less efficient), just to accommodate someone that is deliberately trying to make the truck fail. It isn't just the size of the engine, more power means more cooling and less efficiency. The engine of an ICE truck needs the power and cooling to handle the worst case scenario, and the battery in an EREV needs to do the same. The gen-set in an EREV does not.

I agree. This is the proper way to design the vehicle.

I was just responding to the specific question. If they can’t maintain 40 mph on the Davis Dam test with a <160 kW engine on the genset, they either have to reduce the tow rating or they have to install a larger engine.

Regardless of what Scout Motors do, there are still ways for the driver to screw up. And of course the influencers will blame the truck rather than the driver.

 

[J Alynn]

Oh and this might be a stupid question, but could you drive on battery power with a completely empty gas tank?

So long as battery is charged I don’t see why not. Have to set mode or know mode exists to do that