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Can electric cars on the highway emulate plane-to-plane refueling?

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Re: Can electric cars on the highway emulate plane-to-plane refueling?

#111

Post by slavik81 »

ashtonkem wrote: post #101
slavik81 wrote: post #94

Earlier quoted context omitted.

Assuming we're resurfacing our roads once every 5 years, if we banned trucks it would take 100x longer to accumulate the same amount of damage, so we'd be able to resurface only once every 500 years? I would expect there to be a significant amount of damage done just by the elements, independent of usage.

There’s also the fact that roads are built up to trucking standards. Without trucks the roads would be thinner, reducing cost and pollution (concrete is a major source of CO2).

Sure. I don't necessarily disagree with your conclusion that trucks undercontribute to road maintenance costs. I just don't think those numbers are sufficient to prove it.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#112

Post by ashtonkem »

throwaway0a5e wrote: post #109
ashtonkem wrote: post #108

Earlier quoted context omitted.

Highways are much more relevant when we’re talking about trucking, and highways are largely concrete.

This is utterly false and in a trivially verifiable way in this age of street view. Raised highways sometimes have concrete decks because the strength can be attractive but the overwhelming majority of highways are asphalt. At or below grade highways are almost always asphalt. Tunnels are often concrete but those are a vanishingly small minority of miles.

If you’re going to call something “utterly and trivially verifiable (sic) false” you should actually check. Interstate highways use more cement than asphalt.

“The analysis shows that a total of approximately 1.5 billion metric tons (Gt) of aggregates, 35 million metric tons (Mt) of asphalt, 48 Mt of cement, and 6 Mt of steel is in place in interstate highways.”

https://pubs.usgs.gov/fs/2006/3127/2006-3127.pdf

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#113

Post by nradov »

ianai wrote: post #57
NickM wrote: post #39

Earlier quoted context omitted.

It was abandoned because fast charging stations keep improving, and are much simpler and cheaper to operate than battery swap stations. It's already at the point where you can take a 400-500 mile road trip in a Model 3 with maybe a single twenty minute charging stop, which is just not that much extra time, and most people like to take a short break every few hours anyway. I suspect Tesla knew this would probably happ…

I’d still like to be able to tow a battery behind me for extended trips. I don’t know how running the AC impacts range, I would like to know. Places with extreme weather and major population centers can make an otherwise short drive really taxing on resources through ac use or just being stuck in place for extended periods of time. Like how peak LV traffic can turn a 15 min drive into a 50 minute drive in 120f+ heat.…

Most drivers aren't competent to tow a trailer, especially not at high speed or reversing.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#114

Post by nitwit005 »

yawgmoth wrote: post #23
jccc wrote: post #9

Asking sincerely: Why should we not simply pull over to do this? Planes obviously are a different situation, but cars can easily just stop. While cool to imagine, it seems unnecessarily complicated and unsafe to do this in motion on the road. [Edit: The prof and his team are quite serious about it, so I assume there must be a reason and I'm actually curious what it might be.]

The non-serious answer is that we need to charge while driving to best emulate F-Zero https://youtu.be/BIe4AvKLSa4?t=217

That was a mid-air repair of another flying vehicle.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#115

Post by wahern »

throwaway0a5e wrote: post #109
ashtonkem wrote: post #108

Earlier quoted context omitted.

Highways are much more relevant when we’re talking about trucking, and highways are largely concrete.

This is utterly false and in a trivially verifiable way in this age of street view. Raised highways sometimes have concrete decks because the strength can be attractive but the overwhelming majority of highways are asphalt. At or below grade highways are almost always asphalt. Tunnels are often concrete but those are a vanishingly small minority of miles.

AFAIU, the original Interstate Highway System was all concrete. These days states usually resurface heavily trafficked segments with asphalt (of various varieties) atop the old concrete. Apparently, at least as of 2006 60% of the system was still concrete pavement: https://pubs.usgs.gov/fs/2006/3127/2006-3127.pdf Which is not surprising as IME long segments of the IHS are often still concrete pavement, especially in the South and West; it's only in urban areas where asphalt surfacing seems ubiquitous.

I'm not sure how new segments are built today, but they may very well still use concrete underlayment, or at least something more substantial than loose aggregate. Road tech these days is way more complicated than just concrete v. asphalt. I would guess that for remote segments, and given the load requirements, it may still be cost effective to keep using concrete surfacing.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#116

Post by munsters »

This seems like it would only work if you're able to stay bumper to bumper with the charging car for 30+ minutes. You'd have to be traveling a very long distance along the same route (and, the charging car's destination MUST be before it runs out of power after transferring its power). What are the odds of that happening, on a reliable basis? At that scenario, it seems more sensible to install overhead wires (or underground) along freeways for long distance travel.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#117

Post by hinkley »

ntsplnkv2 wrote: post #95
ashtonkem wrote: post #17

Why bother? With top line EV ranges reaching close to 400 miles, after that amount of time I need to get out of the car. If you want people to be able travel huge distances cleanly without stopping, then what you’re actually looking for is a train.

Not everyone wants to take an hour long break every 400 miles. On a 2000 mile trip, that's an extra 5 hours of travel time. I'd much rather be at the beach than at Rest Stop X in the middle of nowhere for an hour.

Are you gonna drive 2000 miles straight through or get a hotel?

I did 1800 miles straight through twice, once with three drivers and once with five and both were pretty rough. Would not repeat. Almost had a driver fall asleep at the wheel the second time and I didn’t get to nap after my last turn at the wheel because of it.

If you’re doing it alone, subtract an hour a day for hotels. If you are with a group, then I think some of the other people are right: you’re going to stop more often and for longer than you think you are. Half an hour every three hours will keep you at above half your range and wouldn’t be so bad.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#118

Post by hinkley »

Retric wrote: post #46
ravenstine wrote: post #38

Earlier quoted context omitted.

What reason would that be? I always assumed that was because of the pursuit of slimmer phones and to discourage repair.

It’s also a more complex and expensive. Swapping cellphone batteries means you need to own another battery which few people did once capacity increased. With cellphones people that want a swappable battery can just get an external battery pack but most people can simply recharge daily.

In theory we should be able to have external battery packs for electric cars, but I think the power density would have to about double before that happens. How many miles can you fit in a 30 lbs battery right now? Not very many.

I think that gets you about 10 miles in a Tesla. If it got you 20 miles it might be worth building a few slots into the trunk for extended range.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#119

Post by renewiltord »

leetcrew wrote: post #80
ianai wrote: post #77

Earlier quoted context omitted.

Not really. Yes batteries add lots of weight. But electric motors have lots of torque and are known to climb hills easily. Like how Tesla’s forthcoming truck can tow up to 14000 pounds. I’m not doing the calculus, but I suspect the power characteristics of electric motors more than make up for a towable battery. Edit-here’s an article about a company doing this https://electrek.co/2020/02/19/french-startup-proposes-b…

energy, not power. I'm sure the motors have enough torque to tow the battery, what I'm doubting is how efficiently that extra battery capacity gets converted to range. as an aside, the cybertruck is (probably) pretty bad at towing. see this video for an interesting argument: https://www.youtube.com/watch?v=S4W-P5aCWJs

Very slow video. Wish it were transcripted.

Re: Can electric cars on the highway emulate plane-to-plane refueling?

#120

Post by ashtonkem »

hinkley wrote: post #117
ntsplnkv2 wrote: post #95

Earlier quoted context omitted.

Not everyone wants to take an hour long break every 400 miles. On a 2000 mile trip, that's an extra 5 hours of travel time. I'd much rather be at the beach than at Rest Stop X in the middle of nowhere for an hour.

Are you gonna drive 2000 miles straight through or get a hotel? I did 1800 miles straight through twice, once with three drivers and once with five and both were pretty rough. Would not repeat. Almost had a driver fall asleep at the wheel the second time and I didn’t get to nap after my last turn at the wheel because of it. If you’re doing it alone, subtract an hour a day for hotels. If you are with a group, then I t…

The longest you can drive without stopping is proportional to the smallest bladder in your group.
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