Harvester Talk: Q&A

[CarTechGeek]

Was there ever any conversation about using the frunk space for the harvester and keeping the original size battery pack? I might have missed details, but it looks the harvester location required a smaller battery pack. If the harvester is capable of adding 350 miles range, and a battery has 350 miles range, well 700 miles combined seems like an over the top number. I'd sacrifice the frunk for that in a heartbeat, and if the frunk lid added the benefit of making it easier to access the generator for maintenance purposes, that also seems like a win. Obviously I don't know whether there were engineering challenges present or what other factors that went in to the decision to place the harvester in the rear, but would love to hear about any of the process that happened during the design phases.

Estimates are that they are removing something like 90-100KWh of batteries.

That's potential $10K-$20K and 1200lbs+ of savings, that can offset the cost and weight of the added range extender, so the truck ends up significantly lighter and less expensive.

If they just tried to keep them, it would end up too expensive and too heavy, and be a packaging nightmare.

 

[prattm1964]

Honestly, is there really anyone here that thinks the Harvester is directly attached to the wheels in any way?
That seems to come up a lot, but I'm not sure anyone is actually under the impression that it does that.

 

[thespieler11]

I really hope the harvester doesnt eat into to much battery space. I prefer to primarily run on electric with the harvester only being used for long trips or when towing. Using rough estimates and chatgpt, if the Scout's still have a pure electric range of 350 miles- in order to get to 500 miles estimated range you'd need about 6 gallons of diesel. Here is the ChatGPT response:

ChatGPT said:​

Yes, using a generator to charge the vehicle's battery while driving could slightly change the math because there would be some efficiency losses in the process of converting diesel fuel to electricity and then storing it in the EV battery. Let's refine the estimate to account for these losses.

Updated Calculation​

1. Estimate Charging Efficiency Losses​

Charging an EV battery generally involves efficiency losses of about 10-15%. This means only 85-90% of the generated electricity would actually make it to the battery.
Assuming a 90% efficiency:

• Effective energy needed = 45 kWh / 0.9 ≈ 50 kWh.

2. Diesel Consumption with Efficiency Losses​

To generate 50 kWh, we need to account for fuel consumption based on the generator's efficiency.
Assuming the generator's diesel consumption remains around 0.45 liters per kWh:

• Diesel required = 50 kWh * 0.45 liters/kWh ≈ 22.5 liters.

3. Convert to Gallons (if needed)​

22.5 liters is approximately 5.94 gallons of diesel fuel.

Summary with Charging Losses​

To extend the range of an EV from 350 miles to 500 miles while charging the battery with a diesel generator on the go, you would need:

• 22.5 liters or 5.94 gallons of diesel fuel.

This accounts for both the electricity required and the charging efficiency losses.


I think 6 gallons of Diesel should fit easily without sacrificing much battery space if at all.

 

[Chuckles]

I really hope the harvester doesnt eat into to much battery space. I prefer to primarily run on electric with the harvester only being used for long trips or when towing. Using rough estimates and chatgpt, if the Scout's still have a pure electric range of 350 miles- in order to get to 500 miles estimated range you'd need about 5 gallons of diesel. Here is the ChatGPT response:

ChatGPT said:​

Yes, using a generator to charge the vehicle's battery while driving could slightly change the math because there would be some efficiency losses in the process of converting diesel fuel to electricity and then storing it in the EV battery. Let's refine the estimate to account for these losses.

Updated Calculation​

1. Estimate Charging Efficiency Losses​

Charging an EV battery generally involves efficiency losses of about 10-15%. This means only 85-90% of the generated electricity would actually make it to the battery.
Assuming a 90% efficiency:

• Effective energy needed = 45 kWh / 0.9 ≈ 50 kWh.

2. Diesel Consumption with Efficiency Losses​

To generate 50 kWh, we need to account for fuel consumption based on the generator's efficiency.
Assuming the generator's diesel consumption remains around 0.45 liters per kWh:

• Diesel required = 50 kWh * 0.45 liters/kWh ≈ 22.5 liters.

3. Convert to Gallons (if needed)​

22.5 liters is approximately 5.94 gallons of diesel fuel.

Summary with Charging Losses​

To extend the range of an EV from 350 miles to 500 miles while charging the battery with a diesel generator on the go, you would need:

• 22.5 liters or 5.94 gallons of diesel fuel.

This accounts for both the electricity required and the charging efficiency losses.


I think 6 gallons of Diesel should fit easily without sacrificing much battery space if at all.

And if the generator runs on gasoline and not diesel? Neither has been confirmed, but I doubt diesel will be the fuel of choice. There's been endless speculation since Harvester was announced, but it's pointless until Scout releases more technical information.

 

[thespieler11]

And if the generator runs on gasoline and not diesel? Neither has been confirmed, but I doubt diesel will be the fuel of choice. There's been endless speculation since Harvester was announced, but it's pointless until Scout releases more technical information.

For longevity and efficiency it really should be diesel.

 

[Chuckles]

For longevity and efficiency it really should be diesel.

VW's history with diesel in the USA would put them under a microscope. Diesel means dealing with particulate filters and DEF. Even if a diesel generator was somehow exempt from those emissions, they would catch tremendous flak for pollution.

 

[Jim Nichols]

It's been confirmed it's gas.

 

[R1TVT]

Honestly, is there really anyone here that thinks the Harvester is directly attached to the wheels in any way?
That seems to come up a lot, but I'm not sure anyone is actually under the impression that it does that.

No, I don't think anyone here believes that there is any mechanical connection between the Harvester and the wheels. The discussion is really whether the Harvester will:

1. Serve simply as an onboard generator that will produce electricity that is sent directly to the battery (as described at the reveal)

OR

2. Generate electricity, skip the battery and send some amount of energy to the electric motors via the inverter, akin to some other dubious hybrids (from a performance & user experience perspective) that have done this already.


With option 1, the truck looks, feels and acts exactly like an EV at all times. It's like you are carrying around a mini charger for your battery and running it in the background to help boost your SOC. Performance of the motors and truck is linear in this case, until you reach a critically low SOC (like in all other EV's). At that point, and when the battery is critically low, the expectation would be that you stop and charge (like in all other EV's).

With an onboard generator (like the Harvester), you could theoretically stop and charge your battery (at home or in the woods) with gasoline, reach an acceptable SOC, then drive away for XXX amount of miles before needing more juice.

On a road trip you could also plan a charging stop when you are low, top-off your battery to 100% and top-off your fuel tank. Then you would have another 500 miles of range. There are many unknown variables and many unknown implementation questions, so this won't answer anything at this stage. Eventually, and in time, we will know the size of the fuel tank, engine size & type for the Harvester, battery size (and amount of buffer). Then we will have a better understanding of how the 2 systems will interact with each (and perhaps how this will feel from a UI perspective as a driver).

 

[CarTechGeek]

It's been confirmed it's gas.

As is the EV only range target range for Harvester model of 150 miles.

Forum suggestions can quickly devolve into everyone suggesting their own personal "Homer" mobile. With a market potential of dozens of people.

 

[KarlT]

Forum suggestions can quickly devolve into everyone suggesting their own personal "Homer" mobile. With a market potential of dozens of people.

Homer mobile will be a late addition to the lineup.

 

[Chuckles]

Homer mobile will be a late addition to the lineup.

I want the Flintstones edition. Hard to get more old school than that!

 

[Jim Nichols]

Chevy Volt did both to battery and motor. I think to motor on hills. I think they are going to go with the 3 cylinder VW Turbo motor. Higher Torque at lower RPMs and tuned for plenty of power to keep running as long as there is gas. Just my opinion. This Chevy Volt article and comments has some useful information:

Understanding the Volt's extended range mode

By George Bower In order to understand extended range mode, one must also understand engine maps. The Volt’s engine map looks approximately like this: Notice the term “SFC” or “specific fuel consumption.” The units of SFC are grams/hr of fuel flow per KW of output (g/kwh). Simply put...

www.gm-volt.com

 

[Czernobog]

Ah, the Volt's "Mountain Mode."

Why is it a good policy to always use 'mountain mode' on long trips when driving a Chevy Volt?

Answer: Mountain Mode (MM) simply reserves about half of the battery range, and switches the gas generator on earlier. The idea is that if you are going uphill grade for any sort of distance you will need a bit more power, on average. By having the gas engine running AND a healthy amount of batte...

www.quora.com

 

[R1TVT]

I think that VOLT made 83 HP with the ICE, FWIW...

 

[speedrye]

I think that VOLT made 83 HP with the ICE, FWIW...

Big enough for me for the Harvester. Enough to supply juice driving down the highway at moderate speeds if the battery can't be topped off at a charger.

 

[J Alynn]

Honestly, is there really anyone here that thinks the Harvester is directly attached to the wheels in any way?
That seems to come up a lot, but I'm not sure anyone is actually under the impression that it does that.

Everything implied at the reveal event a handful of us attended was the the Harvester powers the batteries-not the wheels. I’m so confused with all the comments on this thread I’m not sure what people are thinking

 

[KarlT]

I’m just happy about the design on the gas cap door.

 

[prattm1964]

Everything implied at the reveal event a handful of us attended was the the Harvester powers the batteries-not the wheels. I’m so confused with all the comments on this thread I’m not sure what people are thinking

I'm with ya. I don't understand where all the confusion is coming from, it seemed to be pretty straight forward to me.

 

[CarTechGeek]

I'm with ya. I don't understand where all the confusion is coming from, it seemed to be pretty straight forward to me.

What confusion are you referring to? It's seems like there are people creating a strawman, of a mechanical connection to the wheels that they need to correct, yet literally no one is confused about that.

 

[prattm1964]

What confusion are you referring to? It's seems like there are people creating a strawman, of a mechanical connection to the wheels that they need to correct, yet literally no one is confused about that.

That's what I'm saying. I don't see why they are trying to do that, when it is obvious and has been stated that the engine is NOT directly connected to the wheels.