Question about EREV Extended Range EVs on Long Trips (Harvester Gas Engine)

[montgomery]

Hi All-

I have absolutely no EV or Hybrid background and have a question about how EREVs work on extended journeys. I understand that as the charge is depleted the generator kicks on, recharging the batteries. In the case of the Scout it sounds like if you start with a full charge and a full gas tank you would get 500 miles of range.

But let's say you fully deplete the fuel tank on the generator as well as the charge down to basically zero and then stop at a gas station. Are EREV vehicles capable of giving you the full published range with only a tank of gas for the generator AND a depleted battery, or is the full range predicated on starting with a full charge AND a full tank of gas.

Obviously we don't know how the Harvester system itself works, but if anybody with a currrent EREV could chime in how their vehicle works I'd love to hear about it, specifially what the range difference is when you're only able to refill the fuel tank and not the battery as well.

 

[Probity]

Sorry but I can't shed any practical experience feedback, I've had/driven ICE-only since 1969. I reckon it might be 1-2 years before we have any hard answers to detailed workings of the EREV system, we've got a wait for sure.

What happens when A/C is run for extended periods (I live in sweat-box S. LA), will the IC engine have auto stop-start, will it be a 3 or 4 cylinder (my SWAG is something in the 1.5-2 liter range but who knows, hope like hell it's a MPFI naturally aspirated engine and not forced induction), what might a range estimate be in a typical gridlock hurricane evac scenario (that's 50% of the reason I opted for the range extender, I'd still plan on putting a 15 gal. or so gas fuel transfer tank in the bed like I currently do with my ICE PU), what happens to payload when you opt for the range extender, and on and on.

If in 1-2 years I find the actual Scout specs don't meet my expectations, I get my $100 refunded and go to whatever Plan B is out there.

 

[GarageMahal]

This is something we can only theorize about at this point however it seems unlikely to me that it would wait until the battery was depleted to start charging as I doubt the "engine" will provide enough power on its own.

My guess is that once a "low" battery level is reached, the generator kicks in and charges to a "high" battery level. Ideally these "low" and "high" setting will be user adjustable.

 

[Registered User]

Depends on how big the gas tank is. If it’s anything like the now-discontinued Chevy Volt, the ICE engine can keep up with recharging the battery while you’re driving, meaning you can go for as long as it’s got fuel. The Volt had an 8.9 gallon gas tank. We’ll see what the Scouts come with.

Do note: the Scout will be nowhere near as efficient as the Volt, which got around 40 mpg when running in gas regen mode. With the aero, weight, and tire size of the Scout, you’d be lucky to get half that. So if the gas tank is 10 gallons and it can recharge the battery for 20 miles of range per gallon of gas, then you’d get around 200 miles if you were starting with a full gas tank and zero charge. You can sort of see something like this in the published stats. 350 miles for the EV. 500 for the Harvester, so that would be around 150 miles of range on gas once the battery was depleted.

So let’s imagine you’re out in the wild, exploring in areas that have gas stations but zero charging infrastructure. Based on the above, you’d be stopping for gas every 110-130 miles or so.

 

[mackgriggs]

I bet its going to be more like 150 miles on battery and 350 miles on gas with the harvester, similar to the ramcharger with its 145 ev and 555 gas miles (vs the 1500 rev which can get up to 500 miles ev only on biggest battery). The battery size is reduced (even said so in the reveal video) to fit the gas tank, so it can't have 350 miles EV range when the non-harvester version is 350 miles ev range with full size battery.

 

[montgomery]

I bet its going to be more like 150 miles on battery and 350 miles on gas with the harvester, similar to the ramcharger with its 145 ev and 555 gas miles (vs the 1500 rev which can get up to 500 miles ev only on biggest battery). The battery size is reduced (even said so in the reveal video) to fit the gas tank, so it can't have 350 miles EV range when the non-harvester version is 350 miles ev range with full size battery.

That makes sense, I think I saw the 150 mile battery-only spec for the Harvester somewhere but can't find it now. I suppose in that case, after you deplete the initial charge and gas tank you'd be at about 350 miles range per fill up, which isn't terrible.

 

[MnLakeBum]

It’s anyone’s guess how much the range will be with the gas engine once the battery is dead. We don’t know what size the Harvester battery will be compared to the all electric model. Here’s an article about it where the CEO indicates the gas + version will have a smaller battery.

https://insideevs.com/news/738757/scout-range-extender-gas-option/

 

[MnLakeBum]

That makes sense, I think I saw the 150 mile battery-only spec for the Harvester somewhere but can't find it now. I suppose in that case, after you deplete the initial charge and gas tank you'd be at about 350 miles range per fill up, which isn't terrible.

It would also allow us to drive it the 1,900 miles down to FL from MN without having to stop and charge like we do each October and May. We are about to make that Journey next week. I’m too impatient to make that trip in a BEV.

 

[JP1]

That makes sense, I think I saw the 150 mile battery-only spec for the Harvester somewhere but can't find it now. I suppose in that case, after you deplete the initial charge and gas tank you'd be at about 350 miles range per fill up, which isn't terrible.

I caught that also, Battery half the size of the EV.
so guessing roughly 175ish battery and 300-325 on dino juice.

 

[Beach_Bum]

Since we are discussing hypotheticals, if one swaps the coil pack on the generator, then it would in theory charge the battery quicker on less fuel giving an even greater extended range than the OEM 500 miles. I look at it as no different than tuning an ICE for better performance. Someone will "tune" the generator, to gain efficiencies.

 

[DriveAllNight]

Not an engineer - don't play one on TV, but I'm pretty sure a generator cannot keep up with the battery usage needed to drive down the road.

Meaning as the battery gets depleted, the generator will start charging it back up, but the power going in will in no way match what is going out, but it will extend the milage.

So you will never be able to go out with an empty battery and a full tank of gas and expect the car to move.

Plus that two way flow of electricity in and out of the battery, will generate a lot of heat, which will have to be handled with some cooling, which will also deplete resources.

I'm also thinking, this type of usage will shorten the battery life.

Anyway, this is my understanding, unless someone has 'built the better mousetrap' and my knowledge is outdated, which is possible.

 

[Scooby24]

Not an engineer - don't play one on TV, but I'm pretty sure a generator cannot keep up with the battery usage needed to drive down the road.

It definitely can. The real world example is the BMW i3. With just a small 25kw generator, it can keep the battery at a charge target. The Ramcharger is going to have a 130kw generator. It's HIGHLY unlikely Scout will have that powerful of a generator...I'd guess something like 60-75kw. The engine would likely vary the RPMS and generator output to meet the average demands being asked of the battery.

Meaning as the battery gets depleted, the generator will start charging it back up, but the power going in will in no way match what is going out, but it will extend the milage.

So you will never be able to go out with an empty battery and a full tank of gas and expect the car to move.

Plus that two way flow of electricity in and out of the battery, will generate a lot of heat, which will have to be handled with some cooling, which will also deplete resources.

I'm also thinking, this type of usage will shorten the battery life.

Anyway, this is my understanding, unless someone has 'built the better mousetrap' and my knowledge is outdated, which is possible.

Watch this:

And then this:

I don't think Scout will be trying to target the same behaviors as the BMW i3, which was more handicapped in the US where you couldn't set a charge target. I sincerely hope Scout does allow us to set a charge target where you're not using the range extender only as a last hope when the battery is nearly fully depleted as this is both bad for the battery and also would have to severely limit your output to keep you from depleting the last bit of charge you have.

 

[Noplacelikeloam]

The ZEV credit system raises even more questions . . . good video.

 

[dleepnw]

Not an engineer - don't play one on TV, but I'm pretty sure a generator cannot keep up with the battery usage needed to drive down the road.

Meaning as the battery gets depleted, the generator will start charging it back up, but the power going in will in no way match what is going out, but it will extend the milage.

So you will never be able to go out with an empty battery and a full tank of gas and expect the car to move.

Plus that two way flow of electricity in and out of the battery, will generate a lot of heat, which will have to be handled with some cooling, which will also deplete resources.

I'm also thinking, this type of usage will shorten the battery life.

Anyway, this is my understanding, unless someone has 'built the better mousetrap' and my knowledge is outdated, which is possible.

interesting thought. how does this impact battery life? is it the same impact as just plugging in the vehicle to charge? is part of the battery charging while another part discharges? no idea how this works.

 

[Noplacelikeloam]

If it really is 150 battery range then they wont qualify for ZEV credits. This may be a moving target until they get the sales and margin forecasts in better shape.