5klbs towing cap with gas range extender?

[J Alynn]

Some things to keep in mind

• Scout has not provided official towing numbers for the Harvester configuration, the 5,000 number was speculative from the Jay Leno video. The official word from Scout representatives is that total towing capacity for the Harvester (for both Traveler and Terra) is still TBD.
• The reason for the lower tow rating has nothing to do with battery chemistry. That was speculation from a member that has no factual basis. The only thing we know about the battery in the Harvester is that they have changed the battery location in the Harvester setup to move the battery forward to help with weight distribution.*
• They have not said which of vehicles will be released first. There is no statement from Scout about the BEV or the EREV coming out first, and we likely will not be told anything official until much closer to release. The story that the EREV was coming out first was some YouTuber that was talking about the RAM BEV being cancelled in favor of the EREV, and they made a wild ass guess that Scout Motors would do the same thing.

* This info was provided in a thread that was discussing the tow capacity. My theory is that the original design of the Harvester had the battery rear of center (just in front of the rear axle) with the gas tank forward (just behind the front axle) to help balance the weight. They discovered this adversely impacted the maximum tongue weight which directly reduces the total towing capacity. Jamie mentioned that they have updated the Harvester layout to put the battery forward and fuel tank behind it. I would bet that part of the reason for this is to improve the towing capacity. If this is the case, it was weight distribution that was impacting the total tow rating for the Harvester.

Great job providing that info. Was well written

 

[BeerParty]

As @BeerParty notes, they have done some geometry adjustments and given that it sounds like they’ve decided to put the Harvester forward of the rear axle, that pretty much solves the issue of tongue weight.

Just to be clear - the message I saw said they were putting the gas tank for the Harvester EREV further to the rear (behind the battery) in the center section of the vehicle. I have not heard anything about them changing the location of the engine (generator). I have seen conflicting info about where the engine is going to be. I have seen reliable sources say the engine will be "in front of", "above", and "behind" the rear axle.

 

[SpaceEVDriver]

Just to be clear - the message I saw said they were putting the gas tank for the Harvester EREV further to the rear (behind the battery) in the center section of the vehicle. I have not heard anything about them changing the location of the engine (generator). I have seen conflicting info about where the engine is going to be. I have seen reliable sources say the engine will be "in front of", "above", and "behind" the rear axle.

I thought I saw something from a SM employee on here recently that the Harvester would be forward of the rear axle with the battery shifted forward and the fuel tank shifted to the rear. But I could easily could be misremembering or misinterpreting.

 

[cyure]

I thought I saw something from a SM employee on here recently that the Harvester would be forward of the rear axle with the battery shifted forward and the fuel tank shifted to the rear. But I could easily could be misremembering or misinterpreting.

It would be @Jamie@ScoutMotors He’s the one who posts that kind of stuff. I don’t pay as much attention to towing things since I don’t tow so I don’t remember.

 

[smc2023]

Some things to keep in mind

• Scout has not provided official towing numbers for the Harvester configuration, the 5,000 number was speculative from the Jay Leno video. The official word from Scout representatives is that total towing capacity for the Harvester (for both Traveler and Terra) is still TBD.
• The reason for the lower tow rating has nothing to do with battery chemistry. That was speculation from a member that has no factual basis. The only thing we know about the battery in the Harvester is that they have changed the battery location in the Harvester setup to move the battery forward to help with weight distribution.*
• They have not said which of vehicles will be released first. There is no statement from Scout about the BEV or the EREV coming out first, and we likely will not be told anything official until much closer to release. The story that the EREV was coming out first was some YouTuber that was talking about the RAM BEV being cancelled in favor of the EREV, and they made a wild ass guess that Scout Motors would do the same thing.

* This info was provided in a thread that was discussing the tow capacity. My theory is that the original design of the Harvester had the battery rear of center (just in front of the rear axle) with the gas tank forward (just behind the front axle) to help balance the weight. They discovered this adversely impacted the maximum tongue weight which directly reduces the total towing capacity. Jamie mentioned that they have updated the Harvester layout to put the battery forward and fuel tank behind it. I would bet that part of the reason for this is to improve the towing capacity. If this is the case, it was weight distribution that was impacting the total tow rating for the Harvester.

BeerParty, interestingly enough, when I have theoretical conversations with any AI chatbot of your choosing, the answer is almost always the same - It is the batteries. LFP batteries are less capable for delivering "power bursts" - i.e., the high instantaneous torque or power needed for heavy towing. I'm guessing Scout cannot solve this, just like any other truck EV manufacturer. Also this bit of info from AI conversation -
Compared with higher-energy-density chemistries (like NMC / NCA / NMCA), LFP typically offers lower energy density per weight/volume.
That means to get the same range (or enough power reserve for heavy towing), an LFP-based pack needs to be larger/heavier — which can impose design compromises (weight, space, cost) especially on consumer-truck platforms. As a result, many high-towing modern EV trucks still use nickel-based chemistries (NMC or variants) to balance energy density, power output, and towing performance. /// So, for now - I'm confident in my decision to switch to BEV Scout. I want a real capable truck, not a Hyundai Santa Cruz capable truck. Apologies if anyone here owns one of those.

 

[MClayton]

I thought I saw something from a SM employee on here recently that the Harvester would be forward of the rear axle with the battery shifted forward and the fuel tank shifted to the rear. But I could easily could be misremembering or misinterpreting.

This was in a November post on the forums:

Nice update from Jamie at Scout Motors -

A very early cutaway/rendered image we showed had the gas tank up front. We have since moved it under the rear seat area (like typical vehicles) and that allows us to move the batteries to the front for better weight distribution as they are heavier than even the full tank of fuel and engine/generator.

 

[Schubie]

As @BeerParty notes, they have done some geometry adjustments and given that it sounds like they’ve decided to put the Harvester forward of the rear axle, that pretty much solves the issue of tongue weight.

The next issue is thermal management.

My speculation:
They may have to lose a bit of payload to a secondary heat pump to manage the genset engine’s thermals. There’s not really any other great way to cool the engine than with a heat pump with its radiator up front, and it’s probably better to have one heat pump for the genset and one for the motors and battery. If they can manage the Harvester’s engine temperatures properly, they won’t lose much/any towing capability. But the SAE test is brutal and I suspect they’ll have to perform that test with a low to 0% state of charge on the battery to safely and properly rate their Harvester’s gas-only capabilities. This means that if they don’t want to lose tow rating with the Harvester, the genset will have to produce all of the power required to pull 10k and 7k pounds up the Davis Dam hill at 40 mph with the AC running on a 100+ F day. My quick, back-of-the-envelope estimate is that this shouldn’t be a huge problem. The engine they’re likely to choose can be tuned to produce more power than necessary for this pull.


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I hadn't thought of using a heat pump instead of liquid cooling for the Harvester's ICE. Given that later model (water-cooled) 911's seem to provide a good template in terms of thermal mgmt. Curious to hear your thoughts on how the two approaches compare...

 

[SpaceEVDriver]

I hadn't thought of using a heat pump instead of liquid cooling for the Harvester's ICE. Given that later model (water-cooled) 911's seem to provide a good template in terms of thermal mgmt. Curious to hear your thoughts on how the two approaches compare...

The location of the Harvester engine (midship) and the likely desire to retain the frunk suggests to me a more efficient thermal management solution for the Harvester engine would be to use a heat pump and a heat exchanger to exchange heat with the normal antifreeze liquid in the engine.

A couple of advantages include:

• The ability to warm the engine in the garage without combustion. Run the electrical heat pump to heat up the antifreeze and pump that hot liquid through the engine. This would enable getting the engine to be ready to use immediately without the danger of carbon monoxide in the garage.
• Keeping the battery warm during the very cold could be a lot easier by using the waste heat from the Harvester engine. Having a heat exchanger within the system would enable more efficient battery use.
• Improved thermal management and rapid response to thermal changes.
  • Towing up a hill, for example, might suddenly increase the need for a lot more thermal management. A heat pump can create that response much more quickly than any other thermal management solution.

It might be more complex to include a heat pump. But I think it would be a much better solution.

 

[Schubie]

The location of the Harvester engine (midship) and the likely desire to retain the frunk suggests to me a more efficient thermal management solution for the Harvester engine would be to use a heat pump and a heat exchanger to exchange heat with the normal antifreeze liquid in the engine.

A couple of advantages include:

• The ability to warm the engine in the garage without combustion. Run the electrical heat pump to heat up the antifreeze and pump that hot liquid through the engine. This would enable getting the engine to be ready to use immediately without the danger of carbon monoxide in the garage.
• Keeping the battery warm during the very cold could be a lot easier by using the waste heat from the Harvester engine. Having a heat exchanger within the system would enable more efficient battery use.
• Improved thermal management and rapid response to thermal changes.
  • Towing up a hill, for example, might suddenly increase the need for a lot more thermal management. A heat pump can create that response much more quickly than any other thermal management solution.

It might be more complex to include a heat pump. But I think it would be a much better solution.

Great thoughts; thanks!

 

[J Alynn]

The location of the Harvester engine (midship) and the likely desire to retain the frunk suggests to me a more efficient thermal management solution for the Harvester engine would be to use a heat pump and a heat exchanger to exchange heat with the normal antifreeze liquid in the engine.

A couple of advantages include:

• The ability to warm the engine in the garage without combustion. Run the electrical heat pump to heat up the antifreeze and pump that hot liquid through the engine. This would enable getting the engine to be ready to use immediately without the danger of carbon monoxide in the garage.
• Keeping the battery warm during the very cold could be a lot easier by using the waste heat from the Harvester engine. Having a heat exchanger within the system would enable more efficient battery use.
• Improved thermal management and rapid response to thermal changes.
  • Towing up a hill, for example, might suddenly increase the need for a lot more thermal management. A heat pump can create that response much more quickly than any other thermal management solution.

It might be more complex to include a heat pump. But I think it would be a much better solution.

Not my realm but I remember early on Scott said they had a very innovative solution for thermal management. Will be interesting to discuss when they provide more information