Overlanding Range

[Luke42]

I don't think off-road expedition use is going to be the forte of the Cybertruck. Just because you are going slower off road does not mean you consume less energy

Going slower does mean you experience a lot less air drag.

But you likely experience more rolling resistance, because you're off-pavement, may have uneven terrain, and may have reduced tire pressure.

I don't know which factor is dominant. I'd say it's time to start measuring things.

A hybrid pickup truck (like the Chevy Silverado Hybrid or GMC Sierra Hybrid) is probably the best model available to measure this tradeoff. It's not a great model, because its not-as-good-as-the-Cybertruck aerodynamics are going to exaggerate the savings from driving more slowly -- but the CVT keeps the gas engine in its sweet-spot at a wider range of torque*speed requirements, so the ICE and gearbox quirks will be minimized. As I said, it's an imperfect model.

Alas, I'm too busy working to go out and measure this at the moment.

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[Firetruck41]

this makes me wonder what the sweet spot is for an EV that has been optimized for aerodynamics. I've heard about people high-miling by driving their cars no faster than 55 and using cruise control extremely religiously. I'm sure there is a optimized curve for electric vehicle mileage much the same way as with ice cars.

Has anyone done a study on that? I bet with the suspension lowered and a reasonable freeway speed you can totally beat those stop and go numbers, my physics brain is itching to see some plots.

I'm sure there have been studies on this, but anyone with an electric car can tell you that your range is much further at lower speeds vs freeway speeds. I have a Leaf and Bolt and I think the sweet spot is around 30-35 mph.

 

[ThomasG]

This is not true. You lose twice as much energy (velocity squared actually) from going half again as fast.

So you use significantly more energy at freeway speed than at cautious road speed.

In stop and go traffic, an EV can go half again as far as it can on the freeway. On a country road, with no such constraints as traffic, you could double your range.

It's weird, I know, but slow is the new fast with an electric motor.

-Crissa

Road vs off road. Pavement has less friction than dirt, rocks and sand. Expedition folks tend to look for rough terrain.

 

[ThomasG]

this makes me wonder what the sweet spot is for an EV that has been optimized for aerodynamics. I've heard about people high-miling by driving their cars no faster than 55 and using cruise control extremely religiously. I'm sure there is a optimized curve for electric vehicle mileage much the same way as with ice cars.

Has anyone done a study on that? I bet with the suspension lowered and a reasonable freeway speed you can totally beat those stop and go numbers, my physics brain is itching to see some plots.

Concur for on road, but lowering the suspension for off road use is contraindicated. Actually, for the best off road capabilities, things that are as big as the F350 and Cybertruck are contraindicated. Yes, they can have some great attributes, but sheer size can be a major issue. Attack and departure angles also matter. It is hard to beat a Jeep or Polaris for real off road capability. The Cybertruck promises to be quite a vehicle, but everything has limitations.

 

[Crissa]

The sweet spot varies by the particular vehicle, the path you're following, air speed, and motor gearing. Most cars aim for 55, yes, but aerodynamics means that 30 is usually better. My Nova loved 65, despite its brickyness.

Road vs off road. Pavement has less friction than dirt, rocks and sand. Expedition folks tend to look for rough terrain.

Dirt doesn't eat up that much rolling resistance with large wheels. I can barely notice it in my Mazda, let alone a truck. And yes, I do know it exists, but rolling resistance has never been more than a 10% loss of efficiency while wind can be more than 50%.

I said, 'as long as you're not rock-crawling' because that'll eat up who-knows-how-much based upon your ability.

-Crissa

 

[BillyGee]

I wonder if the CT will have ATIS tied to its compressor, that'll also help with range since wheel resistance can be minimized by just managing tire air pressure.

 

[ThomasG]

This is not true. You lose twice as much energy (velocity squared actually) from going half again as fast.

So you use significantly more energy at freeway speed than at cautious road speed.

In stop and go traffic, an EV can go half again as far as it can on the freeway. On a country road, with no such constraints as traffic, you could double your range.

It's weird, I know, but slow is the new fast with an electric motor.

-Crissa

You keep saying road. We are talking about off road, that is, pavement vs dirt, rocks, sand and mud. You will use more energy to cover the same distance off road as you would on road if you keep everything else the same. The people I know who do expedition driving very seriously feel that you get about 1/2 the range off road as you do on road, but that can vary widely.

There are a lot of places where people do this stuff and they will be a long way from a charger. You can't carry enough extra batteries and solar without compromising payload or parking for extended periods. Every pound you add to extend range in this matter will reduce range as well. A five gallon jerry can weighing perhaps 40 pounds will provide 50+ miles of range and occupy a fairly small amount of space. Since it is burned as it is used, it will be lighter while batteries and solar panels do not go down in weight. A Powerwall is 250 pounds and would add what, 30-40 miles? Unless you are a lot richer than I am, you will be stuck bringing it home and carrying all that dead weight. For the volume of one Powerwall, you get 20 gallons of gas for 160 pounds of initial weight and about 200 miles of range.

Short distances off road from locations with chargers will be fine within the constraints of the size of the thing and real world performance which we have not yet seen. What I am talking about is actually going out in the boonies and staying there for a while covering 400-500 miles. People do this and that appeared to be what the original poster was asking about.

EV's are great solutions for many uses, but not yet for all uses. The may well supplant the ICE which some people seem very emotional about. I don't really care, I just want something that does what I need for a reasonable price. EV's are getting there and I remain very interested in the CT. I will not, however, invest my emotions in something that can't return them.

 

[Crissa]

You keep saying road.

You keep saying Powerwall. Half of a Powerwall is inverters and battery tending equipment - not energy holding cells. It's not a good comparison to a battery pack to extend your range.

Here we have 22kg per 3.5kWh module:
https://insideevs.com/news/411676/sparkcharge-portable-ev-charger-roadside-assistance/

And even so, a Cybertruck with a generator and fuel would be more efficient than any ICE solution currently available.

Clearly, you don't know what you're talking about. So maybe instead of not actually contradicting me and thinking I don't have a clue....

Maybe I do go beyond the pavement.

-Crissa

 

[Firetruck41]

You keep saying road. We are talking about off road, that is, pavement vs dirt, rocks, sand and mud. You will use more energy to cover the same distance off road as you would on road if you keep everything else the same. The people I know who do expedition driving very seriously feel that you get about 1/2 the range off road as you do on road, but that can vary widely.

There are a lot of places where people do this stuff and they will be a long way from a charger. You can't carry enough extra batteries and solar without compromising payload or parking for extended periods. Every pound you add to extend range in this matter will reduce range as well. A five gallon jerry can weighing perhaps 40 pounds will provide 50+ miles of range and occupy a fairly small amount of space. Since it is burned as it is used, it will be lighter while batteries and solar panels do not go down in weight. A Powerwall is 250 pounds and would add what, 30-40 miles? Unless you are a lot richer than I am, you will be stuck bringing it home and carrying all that dead weight. For the volume of one Powerwall, you get 20 gallons of gas for 160 pounds of initial weight and about 200 miles of range.

Short distances off road from locations with chargers will be fine within the constraints of the size of the thing and real world performance which we have not yet seen. What I am talking about is actually going out in the boonies and staying there for a while covering 400-500 miles. People do this and that appeared to be what the original poster was asking about.

EV's are great solutions for many uses, but not yet for all uses. The may well supplant the ICE which some people seem very emotional about. I don't really care, I just want something that does what I need for a reasonable price. EV's are getting there and I remain very interested in the CT. I will not, however, invest my emotions in something that can't return them.

You are probably right that an EV is not ready for long range off road, but an EV will do much better than an ICE as far as efficiency off road. Lets say you are crawling off road and spend 10 hours travelling 20 miles. You basically spent 2 gallons of gas driving 20 miles and 2 gallons of gas all the time you were basically idling and keeping the engine running. An EV spends 5kwH driving 20 miles and 1 kwH keeping the stereo and lights on. Just an example, not saying those are the actual numbers, but that is the idea of the difference between an ICE and EV in that type of situation.

 

[Crissa]

https://photos.app.goo.gl/qj4uY4sJLMJ9NQF3A

After this climb I hadta dig agates out of my wheels after crawling back to the freeway.

A wet day is bad out in the desert. You don't want to sink into the crust and damage the trail.

-Crissa

 

[ThomasG]

You are probably right that an EV is not ready for long range off road, but an EV will do much better than an ICE as far as efficiency off road. Lets say you are crawling off road and spend 10 hours travelling 20 miles. You basically spent 2 gallons of gas driving 20 miles and 2 gallons of gas all the time you were basically idling and keeping the engine running. An EV spends 5kwH driving 20 miles and 1 kwH keeping the stereo and lights on. Just an example, not saying those are the actual numbers, but that is the idea of the difference between an ICE and EV in that type of situation.

I can't argue against that nor am I saying that an EV is wrong for a lot of off road use. The original poster was asking about long range, however and we aren't there yet. I suspect you could do the Paris Dakar Rally in a CT, but the average user won't have that sort of support.

 

[SSonnentag]

EVs could drive on Mars or the Moon. Let's see what type of supply chain it would take to get an ICE vehicle to do this.

My point is, Paris Dakar Rally or Baja 1000 are not valid reasons for (anyone minus a few) to discount driving an EV. Typical off road driving doesn't cover that much distance as these are normally day trips of maybe 100 miles on a long day. A jeep is good for 2-10 mpg during off-road driving and they have 17 gallons of fuel, which is good for 35-170 miles. A pair of Jerry cans will get you another 20-100 miles. I think the CT will be competitive with these ranges.

 

[ituner-HF]

Overlanding by my standards: I like to travel, then camp a few days in remote and beautiful country - then move on to the next, new area. This makes a great time to put out solar and soak up a few miles of range. Overlanding tends not to be just an ongoing car ride. It's truly about the process of discovery, then enjoyment. So, however you do those two things, I wish you the best. I know my CT, and how I set it up, will make this a wonderful thing. peace

Yes, but you can stop by "civilization" when switching spots. I know, it sucks, but solar is not going to cut it. Or.... borrow a gas generator, I won't be ashamed.

 

[ThomasG]

You keep saying Powerwall. Half of a Powerwall is inverters and battery tending equipment - not energy holding cells. It's not a good comparison to a battery pack to extend your range.

Here we have 22kg per 3.5kWh module:
https://insideevs.com/news/411676/sparkcharge-portable-ev-charger-roadside-assistance/

And even so, a Cybertruck with a generator and fuel would be more efficient than any ICE solution currently available.

Clearly, you don't know what you're talking about. So maybe instead of not actually contradicting me and thinking I don't have a clue....

Maybe I do go beyond the pavement.

-Crissa

No need to be insulting. That doe snot look like the sort of off road use the original posters was talking about.

I used the Powerwall as an example because one of the earlier posters suggested using one to extend range, plus, since I own some, I am familiar with them.

Let us compare the Spark and Powerwall, however, just for interest.

The Powerwall has 13.5 kWh. It occupies a bit less than 8,000 cubic inches and weighs 250 pounds.

Each Spark module is about 2,500 cubic inches in volume and weighs 65.4 pounds. Each Spark module is 3.5 kWh so to equal one Powerwall, you need four. That gives us 260 pounds and 10,000 cubic inches. You also need the charger module that sits on top. It weighs 20 pounds and occupies 2,800 cubic inches, so for the Spark to equal one Powerwall, we are now up to essentially 50% greater volume and 30 additional pounds.

All that info came from PDF's published by Tesla and Spark. They can be Googled.

Yes, the Powerwall has stuff in it we may not need, but since it appears able to output 120 or 240 volts, it should be relatively easy to connect it to an EV charger as it is. That said, I don't think it would be a great idea to load batteries into the bed of a Cybertruck for long distance off road use. If you want a vehicle this size for long distance off road use, the new F150 hybrid might be a better answer at 24 mpg city and about 550 miles of on road range. If you are doing distances that don't put you too far from a charger, then the Cybertruck should be good to go.

As to generators, to charge a Cybertruck with a low battery overnight, we are going to have to produce what, close to 100 kWh, correct? Assuming we charge overnight, that would give us perhaps 10 hours of charge time, so we need a 10 kWh generator. You are onto something that the fuel consumption of running a generator overnight to keep your Cybertruck charged will probably be less than the fuel consumption of an ICE off road vehicle. I have no desire, however, to camp with a generator running. The other option would be to run the generator while in motion. I do not currently own an EV, so I don't know if they can be charged while moving. All that said, a generator that will produce enough power is about 60,000 cubic inches in volume and weighs 350 pounds or more. Don't forget the gas. Further, the average 4 stroke small engine probably pollutes more for the amount of energy produced than a modern off road vehicle.

Going off the pavement is NOT the issue. I never said it was. The original poster was asking about long distance off road EV travel. The EV is not ready for that today. If you go 200 miles off road and start from a point that is 100 miles from a super charger, you will have issues. Most of the long distance off road folks I know do that all the time and are sometimes in the boonies for a couple of weeks. A lot of them use solar to avoid generator use at camp sites, but carrying enough solar to generate 50+ kWh/day is not feasible.

We can want the EV to solve all vehicular problems, but it can't, at least not yet. It reminds me of people I know who regularly travel from Atlanta to Tampa to visit relatives. They have a Tesla and a Mazda, I think a CX-5. The LOVE the Tesla with a passion but discovered that the trips from Atlanta to Tampa take about an hour or more longer in the Tesla due to having to stop and charge and they wind up at the relative's home with a flat battery. The relatives live in a condo and there is no way to charge during the visit, so they have charge when they get there. They hate being on the road and like to travel straight through eating from a picnic basket, so the stops to charge really bugged them. As much as they want to dump the Mazda and get another Tesla, they decided to keep an ICE vehicle for these trips. I can't blame them. They know their needs best.

I am thrilled with how capable EV's have become and look forward to them improving, but we have to recognize nothing can do everything.

 

[ThomasG]

EVs could drive on Mars or the Moon. Let's see what type of supply chain it would take to get an ICE vehicle to do this.

My point is, Paris Dakar Rally or Baja 1000 are not valid reasons for (anyone minus a few) to discount driving an EV. Typical off road driving doesn't cover that much distance as these are normally day trips of maybe 100 miles on a long day. A jeep is good for 2-10 mpg during off-road driving and they have 17 gallons of fuel, which is good for 35-170 miles. A pair of Jerry cans will get you another 20-100 miles. I think the CT will be competitive with these ranges.

The Cybertruck probably WILL be competitive with that sort of driving. That is not what the original poster asked about and not what I was discussing. One issue, however, is the Cybertruck will not be able to compete in cross country ability with a Jeep due to size and weight. A better comparison is a Ford 250 or 350. The F150 is generally shorter since most have 5.5 foot beds unless special ordered. This is not picking on the Cybertruck; you just can't put big things into small places. Personally, the Cybertruck looks like a huge bang for the buck which is why I put down a deposit.