Hypothetical off-road range decrease?

anionic1

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So I don’t do much off-roading as it is but the Cybertruck will open up that opportunity to me hopefully. I am guessing any moderate off-roading, let’s say like a level 3 where 4 wheel drive is required much of the time, will greatly decrease range. I would think an off-road vehicle that gets 15 miles per gallon in the city may get 3-5 miles per gallon in 4 wheel off road. Anyone have any educated guesses on what kind of decrease in range one should expect? If this topic is covered already I apologize.
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ajdelange

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Of the loads (power train, wheel slip, drag, inertial, rolling resistance, and gravity) I'd think only the last 2 would become especially significant off road and gravitation only when going up hill with a note that you get much of that back when you come back down. If you are crawling you will be in a less efficient part of the motor's spped/torque envelope and pay a little there. I suspect that muddy, slushy, snowy or just wet trails or dry sand or loose soil will be the most detrimental to consumption and, depending on how "gooey" the substrate is, potentially substantially so.

I imagine conditions to be so variable that it would be very difficult to estimate how much loss is to be expected. I have observed that water on a well maintained freeway roadbed can increase consumption by 20% or more. That's really the only number I have.
 
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ElectricSheep

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In the write-up of Rivian driving in a desert race course their range went from 300 miles to 167 (with regen braking increasing the 137 miles to that number). I would figure a 50% loss as a rule of thumb. They had an additional 600 lbs above the stock 5900 lb curb weight to include water and an additional wheel and tire in case an issue arose during the trip. This of course will consume a lot of that little 4.5 foot bed. They didn't do any real rock crawling, which I bet will even consume energy at a higher rate.

The crazy thing is due to range anxiety he ran the tires at 38 psi (poor ride quality and higher chance of puncture) and no climate control in 100˚ heat. That was necessitated by the inefficiency of the Rivian with a 135 kWh battery only having 300 miles of range.
 

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Depends on the trail/ road. A lot of low speed, low impact 4WD isn't going to have a big impact. If you are racing or rock crawling, battery is going to go fast.

Most days rock crawling you aren't covering a lot of miles. You might cover 5 miles in a day and only half of that is going to be super chunk.

We used to ride mountain bikes along a rock crawling route near Bear Valley California. They would pass us during an easy stretch, then we'd catch them when it got chunky. The whole route was something like 4 miles.

Long multi-day routes are going to be a lot tougher.
 

Crissa

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Yeah, if by off-roading you mean hardpan desert or old forest-service roads, you'll probably actually gain range rather than lose it.

But if by off-road you mean climbing rocks or wading grass, sand, or puddles, well, those things sap power.

-Crissa
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