The One-Ton Problem with Scout’s Harvester Range Extender

[Dana]

If towing were my main use case, sure, that would do the trick. My main use case is driving an SUV around town on battery power most of the time, taking road trips frequently, off-roading occasionally, and hauling a small trailer that is >5k lbs occasionally. A Traveler meets the use case perfectly if it can do the towing. I don't really want to drive a pickup around all the time. Been there, done that.

This answer is confusing. You start by saying main use case is not towing. Use case is around town and occasionally a sub 5K trailer. Then you state if it can’t do the 7K you’re out, lol. If you need less than 5K it feels like you’re fine. Specs aren’t announced yet but it seems, based on your posts, the vehicles aren’t going to make you happy. They can’t be all things to all people, even to me, luckily you currently have a vehicle that meets your needs.

 

[climb2man]

I think the main difference is that Scout is considering a different battery chemistry for the Harvester compared to Full EV Model.

I too am closely watching the (rumored) towing capacity of 5,000 lbs, being that is the one spec that will kill this car for me.

But I will give Scout Motors the full runway of time from now to 2027 of release to figure it out. I have faith they will improve or match the full EV towing capacity of 10,000 lbs being many people are addressing the same concern as you.

 

[cyure]

I think the main difference is that Scout is considering a different battery chemistry for the Harvester compared to Full EV Model.

I too am closely watching the (rumored) towing capacity of 5,000 lbs, being that is the one spec that will kill this car for me.

But I will give Scout Motors the full runway of time from now to 2027 of release to figure it out. I have faith they will improve or match the full EV towing capacity of 10,000 lbs being many people are addressing the same concern as you.

Someone saying the same thing I have been saying. I have faith in SM. They haven’t let me down yet and they have knocked if out of the part with the interior and exterior design.

 

[Chavannigans]

I think the main difference is that Scout is considering a different battery chemistry for the Harvester compared to Full EV Model.

I too am closely watching the (rumored) towing capacity of 5,000 lbs, being that is the one spec that will kill this car for me.

But I will give Scout Motors the full runway of time from now to 2027 of release to figure it out. I have faith they will improve or match the full EV towing capacity of 10,000 lbs being many people are addressing the same concern as you.

Using LFP packs for the Harvester makes a lot more sense than NMC packs.

LFP degrades slower over time, which matters a lot since the Harvester pack will be smaller, and it will be cycled more frequently than the NMC packs. They are also happier with being charged to 100% than NMC.

I posted some videos about an EREV truck that people are testing in Mexico and Australia.

It only had a 2,500kg (5,500lbs) towing rating when it released. They are supposedly going to move from a 1.5 turbo to a 2.0 turbo engine and make some suspension changes to bring it up to 3,500kg (7,700lbs) in their next version due to customer demands and feedback.

But the battery chemistry isn’t as big of a factor in towing capacity. They will still use LFPs in that truck with the higher towing capacity.

Luckily for us, VW has a massive selection of engines, design teams, and engineers to figure things out while we wait. they can also learn from other companies' mistakes like the BYD Shark.

Since Harvester reservations are a majority of the pre-orders (around 80%), I am sure they are listening and trying to figure out a balance between weight capacities and power output.

 

[Time2Roll]

Ultimately the small gasoline engine alone would need to pull what is being towed. Need a V8 or turbo4 to pull 10,000

 

[midwestscout]

Good morning!

We have had several discussions here about this concern and Jamie eventually jumped in and said the towing specs havent been finalized yet, so its safe to assume Scout is aware of our concerns and has some time to see if those numbers can go up.

The added weight of the Harvester is not as much of an issue as its ability to sustain adequate power output to recharge the battery while the battery is powering the vehicle as it goes down the road.

If you are using more energy than the generator can provide you will eventually run out of battery, and need to pull over so it can recharge itself.

How can this be an issue when Ram has said that even when the battery is depleted in the Ramcharger it will still tow the same amount as when the battery is fully charged? It will tow 14k pounds. Even my Jeep Grand Cherokee with a N/A V6 will tow 6,200. There's no reason the Traveler being at least as big as my Jeep shouldn't tow more than it does as it has way more horsepower and torque.

 

[midwestscout]

Ultimately the small gasoline engine alone would need to pull what is being towed. Need a V8 or turbo4 to pull 10,000

Why is that? The harvester engine is just a generator recharging the battery, it won't drive power directly to the wheels.

 

[Chavannigans]

How can this be an issue when Ram has said that even when the battery is depleted in the Ramcharger it will still tow the same amount as when the battery is fully charged? It will tow 14k pounds. Even my Jeep Grand Cherokee with a N/A V6 will tow 6,200. There's no reason the Traveler being at least as big as my Jeep shouldn't tow more than it does as it has way more horsepower and torque.

If the RAM is a true EREV it cannot drive when the battery is fully depleted because there is no physical connection between the engine and wheels. There is no transmission. No transfer case. No driveshafts. Just an engine, a battery, and the electric motors at the front and rear axles.

EV manufacturers usually block off 5%-15% of the battery as a buffer. Some at the top, but most of it on the bottom. If you deplete a battery completely and voltage drops it can fry components and/or cause a thermal runaway situation.


They may be saying it can run in series (Engine-->Battery-->Motors) or parallel (Engine-->Motors) where it sends power directly to the motors and stops charging the batteries temporarily when you need more power than the battery has available. But the battery still has to have a certain level of charge or it will shut the truck down before it reaches that point.

Im sure if you start looking into how towing ratings are factored by engineers youll quickly learn that size is not the deciding factor as much as braking, suspension, axle ratings, steering performance, etc. With EREVs another factor is how much energy you are using as you cruise down the road, and how much the generator can produce to keep up with the energy youre using.

You can probably pull 10,000lbs just fine with either the Terra or Traveler with Harvester, but if the generator is producing around 100kW and youre using 150kw to pull that load.. your generator wont be able to maintain the battery's level of charge and the car will eventually need you to pull over so the generator can recharge the battery.


As I mentioned earlier, the BYD Shark is an EREV and it was limited 5,500lbs due to the generator not producing enough power. They will be releasing a new version soon with a 500cc larger turbo charged engine to bring towing up to 7,700lbs despite the overall size and dimensions of the vehicle being the same.

 

[Chaz26]

If the RAM is a true EREV it cannot drive when the battery is fully depleted because there is no physical connection between the engine and wheels. There is no transmission. No transfer case. No driveshafts. Just an engine, a battery, and the electric motors at the front and rear axles.

EV manufacturers usually block off 5%-15% of the battery as a buffer. Some at the top, but most of it on the bottom. If you deplete a battery completely and voltage drops it can fry components and/or cause a thermal runaway situation.

I assume that's exactly what RAM mean in terms of towing ability. Once the battery level is depleted it's not going anywhere, but it can tow max payload until that happens. I read that the battery in the Ramcharger is about 92kWh but the usable is only about 70kWh so with such a big buffer at the bottom end, that is why it can tow full payload right down to 0%.

 

[Time2Roll]

Why is that? The harvester engine is just a generator recharging the battery, it won't drive power directly to the wheels.

Yes and the generator cannot provide the full power requirements of towing 10,000 pounds. The charge level of the battery will drop as the vehicle is driven.

At some point the battery will be depleted and the vehicle is powered by the generator alone. The vehicle will then be limited to a rather low speed. Especially up a modest grade.

Otherwise the battery would also need to be charged at fueling stops. Nobody buys a normally aspirated four cylinder vehicle to tow 10,000 pounds as it would prove underpowered. Same physics applies to the Scout.

 

[plyable]

This answer is confusing. You start by saying main use case is not towing. Use case is around town and occasionally a sub 5K trailer. Then you state if it can’t do the 7K you’re out, lol. If you need less than 5K it feels like you’re fine. Specs aren’t announced yet but it seems, based on your posts, the vehicles aren’t going to make you happy. They can’t be all things to all people, even to me, luckily you currently have a vehicle that meets your needs.

"A small trailer that is >5k lbs" means "a small trailer that is greater than 5k lbs." The mnemonic device for the '<' and '>' symbols is that the open "mouth" points towards the larger item because it is hungry. Make your middle school teacher proud

 

[plyable]

I think I've said it elsewhere. The powertrain isn't the limiter on tow capacity. It's the GAWR.

Unless Scout adds a new axle option, they have to limit the tow rating so that the allowed tongue weight is 10-15% of the trailer weight. Putting a 250-500 pound engine over the rear axle directly reduces the available, allowable tongue weight by 250-500 pounds. That reduces the tow rating by 2500-5000 pounds.

But they're removing hundreds of pounds of battery where they're adding the engine, so it's not a net gain of the total engine weight.

 

[Time2Roll]

Not just weight matters. A low profile pop-up or Trail Manor style trailer will be significantly better than a full profile.

 

[Chavannigans]

Yes and the generator cannot provide the full power requirements of towing 10,000 pounds. The charge level of the battery will drop as the vehicle is driven.

At some point the battery will be depleted and the vehicle is powered by the generator alone. The vehicle will then be limited to a rather low speed. Especially up a modest grade.

Otherwise the battery would also need to be charged at fueling stops. Nobody buys a normally aspirated four cylinder vehicle to tow 10,000 pounds as it would prove underpowered. Same physics applies to the Scout.

I am not really sure if we can make a comparison to vehicles with ICE drivetrains. Since the engine is not directly hooked up to the motors it might not need a ton of power when flat towing and it will always be in its power band.

You may need a V8 to get your load moving but you dont need all 8 cylinders to keep it moving down the road. Thats why so many auto manufacturers have tried cylinder deactivation to save fuel on the highway.

It will really just come down to them finding a balance of how many watts they can produce to maintain speeds without adding too much weight and/or complicating things with forced induction.


I believe the BYD limits towing at 12% grades and thats where things will get tricky with EREVs.

 

[Time2Roll]

^^^^^ I agree and the compromise seems to be 5000 pounds.

I frequently pull 8,000 with a 260hp F150 and 12% grade is 20 mph full throttle in low gear. I could use an electric boost at times

 

[Chavannigans]

But they're removing hundreds of pounds of battery where they're adding the engine, so it's not a net gain of the total engine weight.

I dont think that there will be a drastic difference in physical battery sizes. The Harvester uses LFP batteries. LFP batteries are less energy dense than NMC batteries. So the Harvester battery may have half of the kWh capacity of the NMC packs but it may not be as physically smaller or lighter than one would think.

Chat GPT claims that there would be a 369lb difference between the heavier NMC pack and the smaller LFP pack. It also claims they should weigh roughly the same when you factor the engine and additional cooling needed.

But the weight isnt really the limiting factor in towing capacity here. It seems to come down to how much weight the rear axle is rated for and how much energy the generator can produce to maintain the desired state of charge.

 

[Chavannigans]

Not just weight matters. A low profile pop-up or Trail Manor style trailer will be significantly better than a full profile.

That seems to be the consensus from people that tow with EVs.

Teardrops and pop ups would probably be the best for effiency and range.

 

[SpaceEVDriver]

But they're removing hundreds of pounds of battery where they're adding the engine, so it's not a net gain of the total engine weight.

It matters where the weight is. The battery will be between the axles. The Harvester would move the weight to be directly over the rear axle, which reduces available user-added load on the rear axle, which reduces available tongue weight for towing.

 

[midwestscout]

Yes and the generator cannot provide the full power requirements of towing 10,000 pounds. The charge level of the battery will drop as the vehicle is driven.

At some point the battery will be depleted and the vehicle is powered by the generator alone. The vehicle will then be limited to a rather low speed. Especially up a modest grade.

Otherwise the battery would also need to be charged at fueling stops. Nobody buys a normally aspirated four cylinder vehicle to tow 10,000 pounds as it would prove underpowered. Same physics applies to the Scout.

Then how does Ram say their Ramcharger truck will be able to still tow max weight even with the vehicle battery depleted and just the generator engine running.

 

[midwestscout]

If the RAM is a true EREV it cannot drive when the battery is fully depleted because there is no physical connection between the engine and wheels. There is no transmission. No transfer case. No driveshafts. Just an engine, a battery, and the electric motors at the front and rear axles.

EV manufacturers usually block off 5%-15% of the battery as a buffer. Some at the top, but most of it on the bottom. If you deplete a battery completely and voltage drops it can fry components and/or cause a thermal runaway situation.


They may be saying it can run in series (Engine-->Battery-->Motors) or parallel (Engine-->Motors) where it sends power directly to the motors and stops charging the batteries temporarily when you need more power than the battery has available. But the battery still has to have a certain level of charge or it will shut the truck down before it reaches that point.

Im sure if you start looking into how towing ratings are factored by engineers youll quickly learn that size is not the deciding factor as much as braking, suspension, axle ratings, steering performance, etc. With EREVs another factor is how much energy you are using as you cruise down the road, and how much the generator can produce to keep up with the energy youre using.

You can probably pull 10,000lbs just fine with either the Terra or Traveler with Harvester, but if the generator is producing around 100kW and youre using 150kw to pull that load.. your generator wont be able to maintain the battery's level of charge and the car will eventually need you to pull over so the generator can recharge the battery.


As I mentioned earlier, the BYD Shark is an EREV and it was limited 5,500lbs due to the generator not producing enough power. They will be releasing a new version soon with a 500cc larger turbo charged engine to bring towing up to 7,700lbs despite the overall size and dimensions of the vehicle being the same.

That's correct they said they won't allow the battery to drop below around 15% I believe...and even then when the amount of useable battery is essentially zero they said the truck will still be able to tow max weight with the generator engine running.