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Towing a Tesla at 70 MPH replenishes battery at fast charger rates

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Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#161

Post by ErikVandeWater »

elihu wrote: post #139
ErikVandeWater wrote: post #27

Earlier quoted context omitted.

> Just embed some wires in the road... No offense but that is the most loaded phrase I've heard this week. That would be a major overhaul of both roads and electric car designs.

Sure, but it would be worth it. The cost is that you'd have to re-engineer maybe ten or twenty percent of major freeways and interstates (like have two miles of charging per every ten to twenty miles of regular road), and you'd need to establish a standard for trucks and passenger vehicles and get automakers to adopt it. (Or make it simple enough that it can be added as an aftermarket kit.) You'd also need to install…

> Sure, but it would be worth it.

Are there really no better investments in electric than tearing up 17,000-35,000 miles of highway to make them slightly more efficient?

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#162

Post by rightbyte »

jeofken wrote: post #84
pcarolan wrote: post #15

We have trains in chicago that reach whiskers up to charging lines above them. Same as the trolley systems in San Francisco. What if every major city to city freeway stretch had these in a lane for electric vehicles?

Volvo did a trial of this. Not sure how it ended up. https://www.volvogroup.com/en/news-and-media/news/2018/sep/v...

There are nasty leak currents when the ground is wet. I wonder of they managed to fix that.

Air wires will probably be the way to go, but those will unfortunately be to high for cars.

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#163

Post by JimTheMan »

ElijahLynn wrote: post #160
sokoloff wrote: post #6

It seems like the tire wear wouldn't be worth it. You're pulling the tires at almost 100 horsepower of energy transfer. Sure, neat for a video gag though.

It is worth it if you run out of battery away from a charger.

I anticipate a future where mobile road repair will carry their own massive batteries by default to restart dead EVs on the side of the road.

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#164

Post by codeismath »

FridayoLeary wrote: post #78
ols wrote: post #56

The most spectacular example of regenerative braking are trains that are used in Scandinavia, heavily loaded with iron ore that is transported to the coast: "In Scandinavia the Kiruna to Narvik electrified railway carries iron ore on the steeply-graded route from the mines in Kiruna, in the north of Sweden, down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on th…

The heavy iron ore is essentially a large battery storing gravitational energy. In a way it's just another natural energy source. Maybe in the future clean power can be generated from pulling down mountains.

Years ago I visited the Seneca Pumped Storage Generating Station [0] reservoir in person. It's a massive man-made lake on the top of a small mountain in Pennsylvania, USA.

They pump water up to it at night (when there is excess energy in the power grid), and let the water out in the day when the demand for energy is high (turning some turbines on its way down).

Prior to visiting I had an intellectual understanding of the concept of pumped storage [1], but I have to admit that it's one heck of an experience when you see it up close and personal. My thoughts standing at the edge of this massively perfect-circle deep lake full of water: "somebody built that... and it's one BIG BATTERY".

If you get a chance to visit one of these, I highly recommend it!

[0] https://en.wikipedia.org/wiki/Seneca_Pumped_Storage_Generati...

[1] https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#165

Post by mdeeks »

bodyfour wrote: post #146
mdeeks wrote: post #113

Earlier quoted context omitted.

Apparently there is already the concept of rail train batteries: https://www.vox.com/2016/4/28/11524958/energy-storage-rail You run the trains up the hill when energy is cheap or, for example, when the sun is out and solar works. Then when you need it, you run the trains down hill to generate electricity. Similar to pumped hydro where they do the same by pumping water up hill and then draining it downhill later. Supe…

It's interesting as a thought, but I don't think it's likely to be large-scale practical. Suppose you wanted to run a normal electric train up a mountain. It would certainly take a decent amount of power but not so much that it would be a big challenge for a city-scale power grid. So far you're not yet talking the scale of power where storing it would really be interesting to a grid. One option to store more power wo…

Yeah the idea is the trains are filled with tons of weight.

In my head it still seems like it would be cheaper than digging out massive reservoirs for pumped hydro. Rail seems relatively cheap even if you do have to replace it regularly because of the wear. It also seems like you could put the rail in all sorts of geographies, big and small. Maybe it isn't worth it unless you go big though... and at that point why not hydro.

It's good questions though. No idea how the economics of it will work out vs pumped hydro.

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#166

Post by waiseristy »

BeefWellington wrote: post #49
devoutsalsa wrote: post #5

I wonder if we'll ever have recharging drones that sense your car is running low, pull ahead of you, and just start towing your car for a ways so you don't even have to stop.

Or you could have dyno-based chargers that work like automated car washes. Pull in to a stall, guided onto the drums, put in gear, go for a coffee. Cons: - Less efficient than using an actual electrical cable. - Requires larger infrastructure space. Pros: - Could work with any brand that has regenerative braking. - Could be adapted into existing automated car washes as a premium feature.

- Increased wear on all powertrain components

- Decrease the lifetime of your tires by 1/2

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#167

Post by kllrnohj »

elihu wrote: post #120

This seems like an interesting solution to the "what to do if my battery runs out in the middle of nowhere" problem. Normally, you'd either have to have to call a tow truck or have someone with a generator come along and recharge. However, towing for awhile (probably at much less than 70 mph for safety reasons) to recharge the battery enough to get to the next town is something that could presumably be done by just a…

Only if any of those passing cars are gas-powered. If the passing cars are themselves also EVs, then there's both more obvious forms of energy transfer, but also you'll be taking that much range (and more) from the EV doing the towing.

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#168

Post by breck »

codeismath wrote: post #164
FridayoLeary wrote: post #78

Earlier quoted context omitted.

The heavy iron ore is essentially a large battery storing gravitational energy. In a way it's just another natural energy source. Maybe in the future clean power can be generated from pulling down mountains.

Years ago I visited the Seneca Pumped Storage Generating Station [0] reservoir in person. It's a massive man-made lake on the top of a small mountain in Pennsylvania, USA. They pump water up to it at night (when there is excess energy in the power grid), and let the water out in the day when the demand for energy is high (turning some turbines on its way down). Prior to visiting I had an intellectual understanding of…

Interesting. The first thought that comes to mind when I see that circle is Apple HQ.

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#169

Post by nimbius »

Just a little conjecture here, but i find the whole experiment fascinating.

A tesla model S is around 5000 pounds. not the lightest car on the road by any standard...but towing it behind a consumer Ford F150 will drag the mileage of the truck to 14MPG. not too shabby compared to your long-haul tractor trailers that get about 6...but thats the free rolling weight of the vehicle, not its weight with regenerative braking turned on. id be very curious to know what the final hitch and tow weights are respectively.

from what i can tell, a supercharger will get you charged in about an hour. so...70 miles? most trucks cant maintain that speed in hills or corners, so unless you live in nebraska, youll be on the road a lot longer than an hour. other states might not let you hit 70 at all....can it be done at lower speeds? given the wind conditions on any given day, you might not be able to safely maintain a 70mph tow. other states (california) impose tow restrictions on just how fast you can go.

RV owners probably wont buy a tesla based on this knowledge but id love to see more data from this kind of testing...could the energy from the regeneration be used to charge RV batteries too? can this regenerative system be applied to trucks to power heaters and air conditioners during layovers and downtime?

Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates

#170

Post by yurishimo »

userbinator wrote: post #159
asdff wrote: post #127

Earlier quoted context omitted.

You can get this sort of benefit with a gas car with a manual transmission too. Engine braking uses no gas, its just your wheels turning your pistons and the friction from all of that slows the car down. Most of the time I only hit the brakes to go from 5mph-0mph in a manual car thanks to this.

Diesel engines in large trucks have a similar feature: https://en.wikipedia.org/wiki/Compression_release_engine_bra... However, unlike regenerative braking, you won't end up with more fuel in the tank afterwards.

The only downside is it can be really loud as you shift down the gear and engine RPMs bounce around. Hence, all the signs when you approach a town that say, "No engine braking".
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