Any one else excited for the Rivian?

Jetboy

 
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So what you are saying is in a straight line mechanical is better? With our Tesla’s it is the other way around. Straight line traction is unbelievable, cournering is where they feel not quite up to par.
Yes. Straight line mechanical is physically capable of greater friction with the underlying surface. That would also apply to a Tesla. It would be faster with mechanical locking differentials than it is with open differentials and traction control. It's the same reason a mechanically coupled 4wd system can stop faster in a straight line on snow/ice than any traction control system (all else equal).

Tesla uses a standard open differential carrier - so in that respect it's no different from any traction control system. It accelerates well because it has the ability to produce a lot of power for a short period of time.

By eliminating the differential the Rivan would lose some potential for traction at the limit. Like any slip sensing electronic system one tire must exceed the threshold of motion before slip is detected and then the system adjusts. Mechanical systems can approach the threshold as a coupled system - and as a result have a higher achievable maximum system friction.

The Rivian will probably never see serious offroad use, and it will probably perform pretty well for its intended purpose. It's not a rock crawler. It's just something that will have to be accepted as a limitation of the design. The tradeoff may be enough more ground clearance that it has offsetting benefits that are more useful. Hard to say until we see them in the wild. I'd love to see them put one in the Baja 1000 or the Mint 400 or similar race.

In the end I think the success or failure of Rivian will come down to the batteries. All the rest is pretty well sorted by now. Electronic drive is pretty basic tech. Lots of factories can build a unibody car/truck. The sales pitch is promising and style wise I think they've done a good job. The nut that everyone is trying to crack is energy density and charge rate. I hope it's great. If it could pull a car trailer or a camper for 300 miles per charge and recharge in 30 minutes - I'll probably buy one myself. I'm not holding my breath though. I think we'll get there soon. Can the Rivian do it? Hopefully they'll get to production so we can find out.
 
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Jetboy

 
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$500 million from Ford - not sure whether that is good or bad. The cash and support is great. Without Toyota's factory and support I don't think Tesla would have ever gotten off the ground. The source is more of the problem. But it does suggest that there's more than vaporware and some test mules.
 
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The real question is, how big of a generator do I need to carry, and how much fuel to recharge my
electric truck in the bush?
 

Jetboy

 
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The real question is, how big of a generator do I need to carry, and how much fuel to recharge my
electric truck in the bush?
I've been told - haven't seen it in person - that the Tesla based sand buggy out there is bringing a pretty big diesel generator on the trailer to recharge.

I think down the road we'll see flexible solar panels that will be on top of your awning. So if you had 2 square meters of roof top solar panels and another 4 square meters of solar on your awning top. And you had 1000w / square meter (that's a common output now) you could have as much as 6kw of solar charging. If it's a 100kwh battery - you'd only need 16 hours of direct sunlight to recharge each day... so - obviously not really going to work very well for a full charge, but maybe you could extend the range at least?

Also it's not totally inconceivable that someone could build on their modular bed a hybrid generation unit that does exactly as you suggest. Turn it into a gas/electric hybrid when you want to go to remote areas? Maybe. It's not totally implausible as an idea. Seems unlikely. But it's maybe possible.
 
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I've been told - haven't seen it in person - that the Tesla based sand buggy out there is bringing a pretty big diesel generator on the trailer to recharge.

I think down the road we'll see flexible solar panels that will be on top of your awning. So if you had 2 square meters of roof top solar panels and another 4 square meters of solar on your awning top. And you had 1000w / square meter (that's a common output now) you could have as much as 6kw of solar charging. If it's a 100kwh battery - you'd only need 16 hours of direct sunlight to recharge each day... so - obviously not really going to work very well for a full charge, but maybe you could extend the range at least?

Also it's not totally inconceivable that someone could build on their modular bed a hybrid generation unit that does exactly as you suggest. Turn it into a gas/electric hybrid when you want to go to remote areas? Maybe. It's not totally implausible as an idea. Seems unlikely. But it's maybe possible.
So even using your math it’s a lot more plausable than you think. The EVs are very efficient. Sunday Wh wife raced her model 3 at the drag strip. It was ~100 miles round trip and 9 full speed runs on the 1/4 mile. That and we used 25.2 kw. We have a 7kw hybrid solar set up with battery backup on our house. I’ve charged the Tesla under back up and can get 240v 32a from our system under full sun.l since it also draws from the battery bank. So that would refill the 25.2 kw in <3.5 hrs.

The thing that’s hard to truly understand is with an EV you try and not run it full to empty. I plug in the Tesla almost every day when I get home. So if you think about off roading in the bush. Under full acceleration runs to 110 mph on the 1/4 mile we were using ~600 Wh/mi around town we use ~230 Wh/mi. I would guess usage off road would be 250-350 Wh/mi. So even on the high end 50 miles of off roading At 350 Wh/mi would be replenished in 2.5 hrs using a 7kw solar set up. So I guess what I’m saying is don’t think of 16 hours of charge at once think of 2.5 hrs of charge a day for 6 days.

And just for fun here is a POV video of my wife smoking a non street legal blown mustang on slicks. In her Tesla model 3 on all season tires. This run was 12.31 @112 mph


And a modified challenger RT, her first run down the 1/4 mile, ever


Later she beat a stock charger hellcat.
 
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So, I guess the smart thing would be to take a 'Siesta' every day on the trail. You know, 2-3 hrs in the middle of
the day at highest sun angle to 'recharge the truck', maybe have a glass of beer and an nap!
 
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So, I guess the smart thing would be to take a 'Siesta' every day on the trail. You know, 2-3 hrs in the middle of
the day at highest sun angle to 'recharge the truck', maybe have a glass of beer and an nap!
Or you could charge in the evening off the battery bank that gets re charged While your our driving during the day. And it depends on where you are my peak solar production right now is 5-10pm.
 
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Waiting on pics from overland expo!! The teasers they’ve sent out look pretty good to me!
 

george_tlc

 
 
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I've been told - haven't seen it in person - that the Tesla based sand buggy out there is bringing a pretty big diesel generator on the trailer to recharge.

I think down the road we'll see flexible solar panels that will be on top of your awning. So if you had 2 square meters of roof top solar panels and another 4 square meters of solar on your awning top. And you had 1000w / square meter (that's a common output now) you could have as much as 6kw of solar charging. If it's a 100kwh battery - you'd only need 16 hours of direct sunlight to recharge each day... so - obviously not really going to work very well for a full charge, but maybe you could extend the range at least?

Also it's not totally inconceivable that someone could build on their modular bed a hybrid generation unit that does exactly as you suggest. Turn it into a gas/electric hybrid when you want to go to remote areas? Maybe. It's not totally implausible as an idea. Seems unlikely. But it's maybe possible.
1000W / square metre is the quoted spec for sunlight hitting the surface of the earth (clear sky, sun mostly perpendicular to the square metre etc). Solar panels (good ones that aren't something in an R&D lab) are maybe 20% efficient on a good day. So, 200W per square metre of electricity is closer to reality. i.e you are a factor of 5 too optimistic. Of course you then need to get that into your EV (not 12V...) batteries.

I'll stick with recharging my vehicles with dinosaur juice versus using that juice to run a generator to then charge batteries out bush :)

cheers,
george.
 

Jetboy

 
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I mistakenly grabbed a number for input not output for a typical panel efficiency for solar panels i have on my own home.

I think the day is not too far off that 1000+ mile range on a battery charge is common and range isn't a concern. Is that day closer to 5 years or 50? I have no idea.

The great thing is that if 99% of vehicles that don't need to go to remote places switch to electric, the issues of pollution and emissions from the few remaining ICE ones become a non-issue anyway. In this case there's probably no reason to spend a lot of effort trying to solve the .01% of vehicles that go off road if the 99.9% of vehicles are replaced.

A lot of people said they'd never give up their horse and buggy. And no one forced them to. Horses are still around. But mostly in the hands of people who really want them. I'd guess the future looks pretty similar for today's vehicles. More options is probably good for all of us.
 
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I hope my next car is either an LX 570 or the Rivian R1T. I think the R1T looks really cool, and they are doing things much more methodically and systematically than Tesla, without losing their edge for innovation. If I can afford it, which is a big if, that will be my next truck. If I can't, I'll probably get a used LX :)
 
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