Harvester Talk: Q&A

[CarTechGeek]

Any concerns of overworking the batteries and possibly getting overheated while driving? You would be pushing out as well as pushing in energy to the batteries when range extender kicks in.

Battery heat is a function of charge/discharge rate, and you can charge much faster than you can discharge, it's the charging side that works/heats the batteries closer to a level that might be a concern.

Also if anything the Range Extender lightens the work the battery is doing. When in EV mode, 100% of the power discharging from the battery. If you turn on the range extender, it might be only 25% coming from the battery. Your battery is almost have a snooze when that is happening. Very low discharge rate.

 

[Logan]

The Ramcharger generates 130 kW from the Pentastar.

Ah, good info. The ramcharger version is defined compared to the normal version.


All this makes me wonder.

Will there be a mode on the harvester option to “please recharge my Scout by running the generator when I’m not in it”? Would be weird, but totally useful. In a place without chargers, you could fill with gas on a road trip, then head to go eat and let it idle away and charge while you ate, then fill up again before you left.

Or the “I’ve got a Jerry can of gas” while out wheeling and dump it in and get it charging before you head out sort of situation.

 

[Galaxy]

Ah, good info. The ramcharger version is defined compared to the normal version.


All this makes me wonder.

Will there be a mode on the harvester option to “please recharge my Scout by running the generator when I’m not in it”? Would be weird, but totally useful. In a place without chargers, you could fill with gas on a road trip, then head to go eat and let it idle away and charge while you ate, then fill up again before you left.

Or the “I’ve got a Jerry can of gas” while out wheeling and dump it in and get it charging before you head out sort of situation.

Unlikely. It will likely face similar regulatory restrictions that the BMW i3 REX faced. It was only allowed to run the range extender if the battery was below ~8% (75% for EU versions, which some in the US modded their i3s to).

 

[Logan]

Unlikely. It will likely face similar regulatory restrictions that the BMW i3 REX faced. It was only allowed to run the range extender if the battery was below ~8% (75% for EU versions, which some in the US modded their i3s to).

Interesting, so you say it was a US gov regulation that only allowed the range extender to run when it dropped below 8%? If so then that would likely point to a larger generator onboard.

As going down to 8% would mean a tiny buffer, and more likely to need to be able to charge at "closer to demand" rates vs having a tiny one that started running the moment you left on a long trip to try to extend from 150miles out to 500 miles.

I do wish we could fast forward time for a bit to get more details .

 

[Jkew]

150 mile range is fine enough for my area, where my daily commute rarely exceeds 30miles. Maybe on a monthly basis I’ll go 60 miles. This will be 97% of my usage.

I have an VW ID.4 and don’t have range anxiety. On long (800+) plus drives the 285 range means I’m stopping just-a-little too often, which is really boring. If I were getting another pure-EV I would prefer 500m electric range, but until we have solid state batteries the harvester is a good compromise. On the long road trip that smaller battery will not take a long time to charge, even if I also have to stop at a gas station as well.

 

[CarTechGeek]

Interesting, so you say it was a US gov regulation that only allowed the range extender to run when it dropped below 8%? If so then that would likely point to a larger generator onboard.

As going down to 8% would mean a tiny buffer, and more likely to need to be able to charge at "closer to demand" rates vs having a tiny one that started running the moment you left on a long trip to try to extend from 150miles out to 500 miles.

I do wish we could fast forward time for a bit to get more details .

That 8% thing was only because BMW was chasing extra EV credits in California. CA had a strange rule that you could get more EV credits with your plug in, but first it had to have more Battery range, than range on gasoline (so there was a further restriction on the tiny gas tank to make sure the Gas range was kept under the Battery range). Then on top of that, you had to exhaust the battery before turning on the Range Extender.

There is no way that Scout will be following those silly rules, if they even still exist.

So, they might indeed have a park and charge mode if you get stuck somewhere without charging, and they will definitely let you turn on the RE early, with most of your EV range left, to stretch out your battery usage.

 

[R1TVT]

@R1TVT this might be a good time to interject your knowledge on what a charge duration is these days. An example like this, with only 50 miles to go cant mean that you are spending the night at a charger.

Time spent at a DCFC station is variable by both vehicle and station, and rates will vary based on SOC of the battery, battery architecture, temperature of battery, speed of the station (they can sometimes be throttled for no good reason when other stations are not), charging curve, etc. Most EV's will charge best somewhere between 20% SOC and 80% SOC. I don't really dork out over rates and speed of charging - I just accept it as part of a road trip. Keep in mind the ONLY time I charge at a DCFC is if I am on a road trip, or if I want front row parking in a mall lot with no spaces available and a DCFC station is open. Thats it.

A new Scout (with a presumably better battery and the new 800V architecture) coupled with potentially better charging speeds at a DCFC station, should see very fast charging speeds.

As an example, and at a Rivian RAN station it took me 35 mins to add 57 kWh (128 miles / partial charge). Rate was $0.359/kWh = $20.48.

To be clear, this is not the cheapest or the fastest DCFC, but it is a good representative average example. And for comparison, and in my old Chevrolet Silverado 2500HD at 14MPG, I would have paid about $35 for the gas equivalent of my $20 charge session:

 

[Chuckles]

I think a 180HP turbocharged 3 cylinder powering a generator would be adequate. Where would the radiator/oil cooler and fuel tank fit? I have a F150 EcoBoost and the 3.5 v6 is 380HP and 400TQ but a simple chip tune and Premium gas it can be 450HP and 500TQ.

130-140 hp is a more realistic output for a 3-cylinder. VW's is only 1.0 liters. They have a 1.5 4-cylinder that produces 174 hp, and their 2.0 L have no problem making over 300 hp. It will be interesting to see what they come up with.

 

[mattbrew]

Exactly my point, enough power to sustain the vehicle itself, but it definitely wouldn't be enough to tow for extended periods. A setting for towing that starts the generator up immediately while slowly using up the battery would be helpful for towing instead of relying on pure battery reserves for any period of time.

I’m sure to get 500 miles of range the gas extender will be running the entire time. Personally I would rather have 350 miles of battery range than reduced battery size and the extender. But the choice is very nice.

 

[CarTechGeek]

I’m sure to get 500 miles of range the gas extender will be running the entire time. Personally I would rather have 350 miles of battery range than reduced battery size and the extender. But the choice is very nice.

Same here. I expect when the full limitations are known, more people will choose the big battery over the RE.

 

[speedrye]

Note that when using an engine as a generator, you have to oversize, and run it at lower than peak output, to not have it under continuous high stress.

The Ramcharger 3.6 Pentastar is a 300 HP (~225KW) engine in normal automotive applications, but in the Ramcharger generator it's max output is 130 KW. That's only about 58% of it's normal max load.


I don't know the size of of the Scout Generator, but it looks fairly small, and the three visible cylinder in the video, kind of hint a 3 cylinder engine. I'd count on significantly less than the 130 KW output of the Ramchargers genset. Like half that or even less.

I think the philosophies are different. I expect the balance here to be more like BMW i3 Rex, where if you flatten the battery, you can barely drive highway speed.

What made the i3 Rex so terrible was that you had a tiny gas tank, and as shipped you couldn't turn on the RE until you flattened the battery, kind of forcing it be a bad experience. With a lower power RE, you need to turn it on at the beginning of a long road trip, to preserve battery.

With the Scout RE, you have 150 Mile range EV for your normal day to day and on a Road trip you start by turning on that generator right away, not waiting until the battery is dead. This way you might pull 75% of your energy from the generator, and only 25% from the battery, and now your battery lasts 4 X as long because most of the energy is coming from the generator. You aren't driving on generator only, but the small generator is enough to supply most, but not all the power you need.

In that sense it really is a range extender, but it doesn't turn into a full normal hybrid when you exhaust the battery. If you try that you will likely face poor highway performance, but you wouldn't be stranded.

I know that will disappoint many people, but it is still a practical solution for longer ranges, and is a probable limitation of a small RE in a big truck.

Note that offroad, I think the small RE would have no problem at all staying ahead of the load requirements, it could likely charge the battery while simultaneously providing all the power you need to move at those slower speeds.

Nice catch on what appear to be three cylinders in the video, but they appear to be on their side. For proper crank lubrication on an inline-3, that would be an all-new engine design. I think what we're seeing is one side of a flat-6 engine. In that case, they should be able to run naturally-aspirated, keeping it more simple. It'd make sense to have a flat-6 turned sideways in there as it'd be quite flat (no pun intended) and fit between the frame rails with the crank/oil pan farther from the rear bumper to improve departure angles. VAG has plenty of experience with horizontally opposed engines. I could be wrong, and maybe it's just half of a flat-6 with added balancers. With the current 4.0 flat-6, that'd give us a 2.0 inline-3. All pure speculation on my end...

 

[Chuckles]

I’m sure to get 500 miles of range the gas extender will be running the entire time. Personally I would rather have 350 miles of battery range than reduced battery size and the extender. But the choice is very nice.

I hear you, but 350 miles seems very optimistic. Is that the EPA rating? Those figures are often wildly optimistic. We shall see.

 

[OIBScout]

I’m sure to get 500 miles of range the gas extender will be running the entire time. Personally I would rather have 350 miles of battery range than reduced battery size and the extender. But the choice is very nice.

It's where my mind is now, and perhaps they'll eek 400 miles out of the battery-only option by the time production models are moving. I assume Scout will happily change my reservation type!

 

[OIBScout]

I hear you, but 350 miles seems very optimistic. Is that the EPA rating? Those figures are often wildly optimistic. We shall see.

Well, let's hope 150 is also not wildly optimistic. Our true range in our Tesla 3 was within about 15% at 70mph + highway speeds. So, 297.5 range (Scout Traveler, battery only) would be not shabby. As long as destination chargers await you at your longer stops, or you are friends with the Tesla network. Scout should buy $1K in Tesla charging credits for owners, as they could probably secure such a below market value with scaled purchasing.

 

[CarTechGeek]

Nice catch on what appear to be three cylinders in the video, but they appear to be on their side. For proper crank lubrication on an inline-3, that would be an all-new engine design. I think what we're seeing is one side of a flat-6 engine. In that case, they should be able to run naturally-aspirated, keeping it more simple. It'd make sense to have a flat-6 turned sideways in there as it'd be quite flat (no pun intended) and fit between the frame rails with the crank/oil pan farther from the rear bumper to improve departure angles. VAG has plenty of experience with horizontally opposed engines. I could be wrong, and maybe it's just half of a flat-6 with added balancers. With the current 4.0 flat-6, that'd give us a 2.0 inline-3. All pure speculation on my end...

I have no idea what those three lumps are, some kind of integrated exhaust manifold/Cat, since you have to cram everything back there.. I just thought three lumps imply 3 cylinder.

I can't imagine them affordably including a Porsche Flat 6. But that would address the power issues.

The RE is definitely the most intriguing element of the design.

 

[Chaparral]

Based on the little information we have I’m thinking the following:

In order to get the full 500 Harvester miles you will need to get the Harvester running almost right away.

Otherwise, under normal circumstances the Harvester kicks in after about 150 EV only miles.

In order to harmonize all the data points I’m estimating that 1) the Harvester normally kicks in when the battery gets to about 50%. 2) The Harvester provides about 40% of the energy needed to run the vehicle.

So on a 500 mile run, with Harvester running right away, the Harvester provides about 200 miles of energy and the battery’s initial charge 300 miles.

This makes the battery “a little bit smaller” to make space for the gas tank as explained during the reveal.

If so, when the Harvester kicks in after about 150 miles of EV only use, there is still about 50% battery and it can potentially extend the range up to about 360 miles. This fits with the website when it says “go a couple hundred more”. (note: this phrase can’t be referring to the Harvester vehicle in comparison to the battery only vehicle because that’s only 150 miles more)

The battery can’t be completely flat after 150 EV miles because that would mean the Harvester would need to provide about 80% of the energy in order to get the 500 miles when running the Harvester for the entire journey - that would mean a big engine that would take up an engine bay.

If this is correct, why would the Harvester kick in when the battery still has 50%? Maybe the battery is a bit smaller and the Harvester is a bit bigger than I’m estimating? However, one problem with range extenders is that they often don’t get regular use, this can be bad for maintenance

 

[speedrye]

Based on the little information we have I’m thinking the following:

In order to get the full 500 Harvester miles you will need to get the Harvester running almost right away.

Otherwise, under normal circumstances the Harvester kicks in after about 150 EV only miles.

In order to harmonize all the data points I’m estimating that 1) the Harvester normally kicks in when the battery gets to about 50%. 2) The Harvester provides about 40% of the energy needed to run the vehicle.

So on a 500 mile run, with Harvester running right away, the Harvester provides about 200 miles of energy and the battery 300 miles.

This makes the battery “a little bit smaller” to make space for the gas tank as explained during the reveal.

If so, when the Harvester kicks in after about 150 miles of EV only use, there is still about 50% battery and it can potentially extend the range up to about 360 miles. This fits with the website when it says “go a couple hundred more”. (note: this phrase can’t be referring to the Harvester vehicle in comparison to the battery only vehicle because that’s only 150 miles more)

The battery can’t be completely flat after 150 EV miles because that would mean the Harvester would need to provide about 80% of the energy in order to get the 500 miles when running the Harvester for the entire journey - that would mean a big engine that would take up an engine bay.

If this is correct, why would the Harvester kick in when the battery still has 50%? Maybe the battery is a bit smaller and the Harvester is a bit bigger than I’m estimating? However, one problem with range extenders is that they often don’t get regular use, this can be bad for maintenance

I'm thinking the battery will be notably smaller to offset the costs enough to make the Harvester option viable. There's been speculation that the Harvester will be the cheaper of the two models.

 

[Jim Nichols]

Probably a good guess. After the 150 miles probably still 20% battery left before Harvester kicks in.

 

[Chaparral]

I'm thinking the battery will be notably smaller to offset the costs enough to make the Harvester option viable. There's been speculation that the Harvester will be the cheaper of the two models.

But the smaller the battery the bigger the Harvester needed to meet the estimates they gave.

Batteries are very expensive. So a reduction of 15-20% might actually pay for a small engine.

They showed us what they think the Harvester will look like. It’s a small engine, so the battery can’t be huge amount smaller.

 

[CarTechGeek]

The battery can’t be completely flat after 150 EV miles because that would mean the Harvester would need to provide about 80% of the energy in order to get the 500 miles when running the Harvester for the entire journey - that would mean a big engine that would take up an engine bay.

If this is correct, why would the Harvester kick in when the battery still has 50%? Maybe the battery is a bit smaller and the Harvester is a bit bigger than I’m estimating? However, one problem with range extenders is that they often don’t get regular use, this can be bad for maintenance

I expect the battery is sized to deliver 150 miles in EV only mode.

I don't think waiting for the Harvester to "kick in" is how it's meant to be used.

My bet: If you are doing a long trip, you start the RE, right away to get blended operation of battery and RE, to extend the range. They can run together for about 500 miles (in something like a 75% RE, 25% battery split), and around 500 miles your battery is empty, and then your speed will drop unless you stop and charge. This is the best way to leverage a small generator as an RE, and get the maximum range out the system.

When you are NOT doing long trips you have a 150 mile range pure EV for your normal day to day usage.

Also, I expect there will be three battery sizes, and cost levels.

• A Standard battery (~100 KWh) you get in the base $60K truck, that has something like 220 miles of Range
• A Smaller than standard battery (~70 KWh) to go with the RE, that has 150 Miles of EV only Range. This will be an extra cost option over standard, but it will cost less than the next option. A little smaller than the standard battery, but a LOT smaller than the Large battery.
• A Very Large (~160 KWh) extra cost pack to deliver about 350 miles of Range. This will be the most expensive option.

That keeps the entry level pricing by having a more reasonable starting pack size, and the RE can be a cost savings vs the Very Large Pack because you are saving an enormous 90KWh of battery, which does cost a lot.