Off Road Range for EV? Jeep 4xe Review / Comparison from TFL

[hola29]

Interesting. I would think that without wind resistance, like at 80mph, the electric torque at low speed would not be wildly inefficient at low speeds. A Jeep needs to be at 4K rpm-ish for max torque. An EV totally different, albeit a lot heavier. We’ll see!

Whatever battery they were extrapolating from… is it confirmed they were talking about the “300 mile” battery and not the “400 mile” pack?

Of course the Rebelle is a moderate speed course, maintaining momentum and rolling on a flat terrain, regardless of dirt or asphalt, is definitely more efficient than the tfl jeep video where they were taking the vehciles up a steep crawling trail where you’re basically at walking speed and increasing in elevation fast.

My point is simply; it will be interesting once we see real world range when rock crawling/running super slow off-road trails.

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[Ssaygmo]

So, I was (Sort of) joking the other day when I commented on a photo of a Rivian out on a dirt road in seemingly middle of nowhere. I basically asked how many panic attacks they've had with range loss on dirt roads. I hope that they have or implement some sort of ability to predict range loss based on anticipated travel surface or if you're "off road" or something. Quick story time for added experience.

I recently drove up to a hike using with about 13 miles of forest road on the way to the trailhead. Gaining about 3,000 feet in the process (on the dirt road).

From home to the forest trail road I drove about 40 miles and used less than 20% of my ID.4 battery at highway speed, gaining roughly 2000 of elevation. So an equivalent of about 200 ish miles of range uphill. Not unexpected.

Of the 13 miles of the forest road, 6 were paved. The rest was a reasonable forest road with some a good amount of potholes. I was generally driving up it at about 15 mph or less. That 13 miles consumed about 15% of my batter. Doing some quick math I'd guess that the gravel portion at up about 12 to 13 percent over the 7 miles. So extrapolating out, that would put me at about 60ish miles of range going ~15 mph at a ~6% grade. It screwed with the GOM in my ID.4 so much that when I got back in the car to go home, it said I wouldn't make it to any charging destinations or home with a 26% charge. I got home with remaining.

So, to summarize:
ID.4 I consistently get 250ish miles range.
Driving uphill at quick speeds having fun, call it 210ish miles.
Going slowly uphill on a gravel road: 60 miles.

This is what I expect in the real world. 50 miles of trail driving at crawling speeds will probably kill the 300 mile r1t pack, but then again that is a HUGE distance to cover off-road, and most people won't do more than 10-20 miles so losing 100 mile of highway range is ok so long as there is a charger near the start of the trailhead.

As some have said, it is also to be expected that the loss on the Rivian should be a bit less than the jeep, due to the fact you aren't experience a zf8 transmission, transfer case, and dana axles to lose energy through before it gets to the ground. BUT you are still lugging around a similar huge amount of weight with a battery thats 115kwh larger than the jeep 4xe pack...

 

[SeaGeo]

This is what I expect in the real world. 50 miles of trail driving at crawling speeds will probably kill the 300 mile r1t pack, but then again that is a HUGE distance to cover off-road, and most people won't do more than 10-20 miles so losing 100 mile of highway range is ok so long as there is a charger near the start of the trailhead.

As some have said, it is also to be expected that the loss on the Rivian should be a bit less than the jeep, due to the fact you aren't experience a zf8 transmission, transfer case, and dana axles to lose energy through before it gets to the ground. BUT you are still lugging around a similar huge amount of weight with a battery thats 115kwh larger than the jeep 4xe pack...

I won't lie, I was surprised by the range hit with seemingly just a gravel road. It wasn't what I'd call "off road" or particularly demanding, and was definitely worse performance than Emme got.

Other than elevation change, I don't think the weight of the battery matters much in this instance. Totally agree with you that a bunch of the loss with the Jeep is associated with power inefficiency. But I suspect that a lot of it is basically the result of road smoothness energy transfer efficiency of the surface. Sand dunes are obviously going to absolutely murder a battery. That's where being either able to have the car guess at surface type as part of the roue planning, or having a software switch for predicted range for different surface types would be really handy. GM's trail energy usage guide would be another great way to handle that with enough data too.

Hopefully Rivian has a way to help people to anticipate that hit to range as part of a larger trip. For example, if someone has 60 miles to a trailhead and plan on 15 miles on a "trail", they'd probably assume starting at a 60% charge is fine and expect to make it back home with say... 10% battery. But they may end up sweating out that return trip home!

 

[njcoach24]

most people won't do more than 10-20 miles so losing 100 mile of highway range is ok so long as there is a charger near the start of the trailhead.

so what’s the solution for this if you want to do more than 10-20 miles in a remote area and no charger near. Also, we are not including the added weight of the extras you might need to carry on an adventure like food/drinks, tent (RTT are heavier than ground ones), other gear. In that video that Jeep didn’t seem to be carrying anything extra.

also I kind of like the solution of hybrid and I’m surprised more companies haven’t moved to improve that tech more. Give everyone enough miles to do their daily commutes but have the gas backup for long trips/adventures where you might not want to waiting for charging and keep it moving.

I still love Rivian but these points need to be discussed. Every time you point out the negatives in this forum the fan boys get wound up.

 

[Smithery]

She also mentioned ~50mile range in the dunes...

Indeed!

I went to college on the central coast of California. We had publicly accessible sand dunes on the beach 20 minutes from campus.

For about 6 mo I was borrowing my brother's 4WD 4-runner. Day-to-day driving, I averaged between 17-18mpg with a roughly even split of highway and city driving.

It definitely dropped to 4-5mpg when spending time out on those dunes.

My R1T will be spending 90% of its life on pavement, and 9.9% on "hard dirt"

Yes, I might take it to some dunes somewhere sometime for some fun.
But for a few miles, not as an attempt to maximize battery range.

 

[opnwide]

I agree with @sevengroove that I believe the 4 independent motors will be more efficient than the 4xe from an architecture standpoint, and will not have losses from all of the mechanical driveline components (transmission, transfer case, differentials).

However, the R1s will be even heavier vehicles, so they have that as an added detriment when it comes to steeper climbing.

It will definitely be interesting to see how these vehicles perform and their range in various types of off road scenarios.

And for another theme from that video, the R1 20s will have more sidewall than the Defender, but I still hope a pair of 17" or 18" wheels might fit around the production brakes!

To Skyote's side-point on the tires, this video cracked me up busting two 20" wheels/tires on that same rock. (I ran into Roman (the dad) in Boulder several months ago when they were in the middle of JLR buying back their first Lemon 4 cylinder Defender and it looked like they were going to get a 6 cylinder with 20's and he told me he was going to miss the smaller diameter steelies. (Roman has been a critic of Rivian in his videos for some time now saying, "The Rivian has been out for so long now it looks like it needs a refresh before they release it.")) The Defender has 255/60/20 tires or approx 6" of sidewall, while the 20" Rivian will have 275/65/20 or about 7" of sidewall. Not sure that gives me tons more comfort on a rated 7 trail like Red Cone, or at least that particular rock, but I'll take an inch more any day!

 

[skyote]

Not sure that gives me tons more comfort on a rated 7 trail like Red Cone, or at least that particular rock, but I'll take an inch more any day!

I actually think the Rivian 20s will be OK, but I also feel confident that smaller wheels will fit...the sticking point might be clearances with wider tires... there's not many suitable tire sizes/options for 17-18" wheels that are as narrow as the 275mm/10.8" Rivian OEMs.

But who am I kidding, I won't be taking my Rivian on serious trails (at least not for a couple years). Maybe I should just use it to tow a Jeep.

@opnwide , and LOL!

 

[SlaterGS]

So, I was (Sort of) joking the other day when I commented on a photo of a Rivian out on a dirt road in seemingly middle of nowhere. I basically asked how many panic attacks they've had with range loss on dirt roads. I hope that they have or implement some sort of ability to predict range loss based on anticipated travel surface or if you're "off road" or something. Quick story time for added experience.

I recently drove up to a hike using with about 13 miles of forest road on the way to the trailhead. Gaining about 3,000 feet in the process (on the dirt road).

From home to the forest trail road I drove about 40 miles and used less than 20% of my ID.4 battery at highway speed, gaining roughly 2000 of elevation. So an equivalent of about 200 ish miles of range uphill. Not unexpected.

Of the 13 miles of the forest road, 6 were paved. The rest was a reasonable forest road with some a good amount of potholes. I was generally driving up it at about 15 mph or less. That 13 miles consumed about 15% of my batter. Doing some quick math I'd guess that the gravel portion at up about 12 to 13 percent over the 7 miles. So extrapolating out, that would put me at about 60ish miles of range going ~15 mph at a ~6% grade. It screwed with the GOM in my ID.4 so much that when I got back in the car to go home, it said I wouldn't make it to any charging destinations or home with a 26% charge. I got home with remaining.

So, to summarize:
ID.4 I consistently get 250ish miles range.
Driving uphill at quick speeds having fun, call it 210ish miles.
Going slowly uphill on a gravel road: 60 miles.

Love me a good story, thanks for sharing!

I like your breakdown of the different scenarios, though I do have a question.

Do you have an idea of your total energy going up to the hike and then separately your energy used coming back and how that compares to a drive that is the exact same distance but on flat roads?

What goes up has to also come down and you hinted at the end that you obviously got home with remaining, but I'm curious as to the offset/usage from worst case combined with the much better case of going down hill.
Driving through the mountains in my ICE vehicle, I see the average mpg drop steadily as I am going up and recover decently (not fully) on the way down. So in the end it isn't the same efficiency as if I were on a flat road, but it also isn't a constant worst case scenario.
It seems people tend to compare worst case and "normal". But I feel like most worst case scenarios finish with best case when we are talking about going up mountains (not rock crawling)

 

[Eager2own]

"The Rivian has been out for so long now it looks like it needs a refresh before they release it."

Upon reading this, I laughed... and then cried.

 

[ajdelange]

I hope that they have or implement some sort of ability to predict range loss based on anticipated travel surface or if you're "off road" or something.

I'm sure they will. A graphical display of SoC vs distance driven with a prediction out to destination suffices. I cannot imagine that Rivian would not have this.

I recently drove up to a hike using with about 13 miles of forest road on the way to the trailhead. Gaining about 3,000 feet in the process (on the dirt road).

Going up hill does not take as much as you might think. For example going up 1000m in a 2500 kg vehicle takes about 1000*9.8/3600/1000 = 6.8 kWh. Going 13 miles in a vehicle that takes half a kWh per mile draws 6.5 kWh. So going 13 miles on a 4.4% grade will about double your consumption. But, of course, you get a good chunk of that 6.8 kWh when you come back down so overall your consumption is not increased by that much going up hill.

Now think about riding your bicycle off the boardwalk onto the beach and think about riding it on a dirt road. A well packed dry dirt road isn't really much harder to drive on than a paved road but the sand requires much more effort. So is it with cars. I have not found that driving dry dirt roads adds much to my consumption. But driving on a wet road does. It takes a lot of work to push water out of the way. Stick your hand in the water next time you are out in your boat while its moving. Its the same with sand and snow. I really think that the nature of the substrate is going to be the biggest determinant of range reduction off road as it is anywhere.

From home to the forest trail road I drove about 40 miles and used less than 20% of my ID.4 battery at highway speed, gaining roughly 2000 of elevation.

Half percent per mile on a 1% grade

Of the 13 miles of the forest road, 6 were paved. The rest was a reasonable forest road with some a good amount of potholes. I was generally driving up it at about 15 mph or less. That 13 miles consumed about 15% of my batter.

1.13% per mile. Six miles on paved would use 3% leaving 12% for the 7 and implying 1.7%/mi which is triple what you get on the paved roads. That seems a lot but if it was loose gravel perhaps not surprising.

 

[SeaGeo]

I'm sure they will. A graphical display of SoC vs distance driven with a prediction out to destination suffices. I cannot imagine that Rivian would not have this.

Something that basic wasn't what I was saying they will clearly have a GOM. But I'm hopeful their GOM includes information about surface type in some way.

Going up hill does not take as much as you might think.

I was implying going uphill was the culprit. Just noting the amounts so as to not mislead people.

That seems a lot but if it was loose gravel perhaps not surprising.

Yep.

I really think that the nature of the substrate is going to be the biggest determinant of range reduction off road as it is anywhere.

I know. That was literally my point.

 

[SeaGeo]

Love me a good story, thanks for sharing!

I like your breakdown of the different scenarios, though I do have a question.

Do you have an idea of your total energy going up to the hike and then separately your energy used coming back and how that compares to a drive that is the exact same distance but on flat roads?

What goes up has to also come down and you hinted at the end that you obviously got home with remaining, but I'm curious as to the offset/usage from worst case combined with the much better case of going down hill.
Driving through the mountains in my ICE vehicle, I see the average mpg drop steadily as I am going up and recover decently (not fully) on the way down. So in the end it isn't the same efficiency as if I were on a flat road, but it also isn't a constant worst case scenario.
It seems people tend to compare worst case and "normal". But I feel like most worst case scenarios finish with best case when we are talking about going up mountains (not rock crawling)

Sort of.

So on the highway to the trail was a little less than 20% used on the way there. I used 6 percent on the way back for the same distance.

The amount if reported for the "forest road" breakout is basically the route up. Unfortunately I have to go off memory at this point, because EVNotify didn't report my data during that time without cell covers, but basically the way downhill on the forest road was energy neutral.

 

[ajdelange]

Something that basic wasn't what I was saying they will clearly have a GOM. But I'm hopeful their GOM includes information about surface type in some way.

GOM?

If you mean a predictor of some sort I think the diversity of potential substrates is so great that it will be nigh unto impossible to come up with a reasonable one.

 

[SeaGeo]

GOM?

If you mean a predictor of some sort I think the diversity of potential substrates is so great that it will be nigh unto impossible to come up with a reasonable one.

Guess-o-meter. A range indicator.

They should have plenty of data based on how much off road mileage they appear to have done to have a reasonably idea as to a ballpark loss in range when you hit a gravel road or go off-roading. Emme literally gave an estimate based on a couple of days of driving herself. You and I both know they have a not-insignificant amount of vehicle data of various road surfaces. ABRP takes a stab at incorporating weather impacts like rain, it's not unreasonable to come up with a different baseline efficiency value for mapped gravel roads or literal trails. GM has actually stated they will have something similar to this for trails specifically for the Hummer.

 

[Gshenderson]

Guess-o-meter.

They already have that for forecasting production dates! ?

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