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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

#221

Post by femto »

AceJohnny2 wrote: post #196
AdamJacobMuller wrote: post #183

Earlier quoted context omitted.

> one BIG BATTERY > The power plant, rated at 451 MW That's a damn big battery. I love pumped storage, too bad it's not used more.

> I love pumped storage, too bad it's not used more Pumped storage is awesome and the most cost-efficient way to store energy. It's used as much as possible, but... I attended a USGS [1] talk about dams (in California) a few years ago. The key takeaway is: all places worth damming have been dammed. There are no more dammable places, hydrologically and geologically speaking. When I drive through the central valley, I…

With pumped storage you don't need anywhere near the amount of water or storage needed for straight Hydro. In a 24 hour cycle, you can empty the top dam into the low dam, running the generators flat chat (unlike typical hydro which is limited by water supply), then pump it back up again for reuse. If you do the numbers (E=m.g.h) the amount of water required to store energy for a city of millions is quite tractable, assuming a decent head.

Australia is doing exactly this with "Snowy 2.0" (by connecting existing dams).

https://www.snowyhydro.com.au/snowy-20/about/

350,000 megawatt hours of energy storage, which is enough to power 3 million homes for a week, or (if there was enough generation/transmission capacity to get the energy in/out fast enough) the entire nation for 12 hours.

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

#222

Post by bigiain »

jashephe wrote: post #193
tshaddox wrote: post #175

Earlier quoted context omitted.

Pumped hydro is really cool. Also really bad when it fails: https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_... > ... catastrophic failure of a triangular section of the reservoir wall and the release of 1 billion US gallons (3,800,000 m3) of water in 12 minutes. The sudden release sent a 20-foot (6.1 m) crest of water down the East Fork of the Black River. > A broad swath of dense forest was washed away…

Taum Sauk is unusual in that the dam fully surrounds the upper reservoir (i.e. the lake was made from scratch), although certainly all types of dam can fail.

All types of dams can be shittily maintained:

https://en.wikipedia.org/wiki/Oroville_Dam_crisis

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

#224

Post by Obi_Juan_Kenobi »

jborichevskiy wrote: post #217

Isn't this just transferring energy from the car towing to the Tesla itself? My understanding is this production of power induces some friction, that otherwise would've been closer to neutral. In other words, if the wheels were completely free to spin, would not the towing car require less power to tow? Or is my understanding of this off? Physics was a long time ago

Yes, there's no claim of free energy or perpetual motion here. The author even discusses approximately how efficient the charging is in the video.

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

#225

Post by bigiain »

ClumsyPilot wrote: post #215
avalys wrote: post #115

Earlier quoted context omitted.

You’re telling me I could fill a typical water tower in 1 hour with a 500 W pump running off a kitchen outlet?

500W is a lot, it is hypothetically enough to move 10 liters of water 50 meters up every second. A motor on a cycle an electric bike is 250w. A kitchen tap provides like what, 0.2 liters per second?

So in an hour that's 36000L of water pumped up into the hypotheticals 1 million gallon tank. Right on the three orders of magnitude short that a previous commenter pointed out.

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

#226

Post by lttlrck »

bin_bash wrote: post #141
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…

On the Long Way Up they did just this to recharge their Rivians

That is a fantastic show. Rivian and Harley (electric bikes) did great.

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

#227

Post by bigiain »

ClumsyPilot wrote: post #216
mikepurvis wrote: post #147

Earlier quoted context omitted.

Right, but that's about maintaining pressure and supply when everyone wants a shower at the same time in the morning, not about harvesting the energy of it all flowing downhill.

Pressure is energy

Nope.

Energy is force times distance. You need to know more than just pressure to calculate energy.

(A bicycle tire at 120psi has a lot less energy than a truck tire at 90psi.)

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

#228

Post by gregwebs »

AceJohnny2 wrote: post #196
AdamJacobMuller wrote: post #183

Earlier quoted context omitted.

> one BIG BATTERY > The power plant, rated at 451 MW That's a damn big battery. I love pumped storage, too bad it's not used more.

> I love pumped storage, too bad it's not used more Pumped storage is awesome and the most cost-efficient way to store energy. It's used as much as possible, but... I attended a USGS [1] talk about dams (in California) a few years ago. The key takeaway is: all places worth damming have been dammed. There are no more dammable places, hydrologically and geologically speaking. When I drive through the central valley, I…

I think you are describing pump-back hydro dams which are only a subset of pumped storage. Strictly speaking pumped storage only requires an elevation change and a water supply

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

#229

Post by twobitshifter »

rpmisms wrote: post #95
furiousjulius wrote: post #83

Earlier quoted context omitted.

Reminds me of this dam operation around here that pumps water up to a mountain top reservoir during the day when power is cheap and then lets it go at night when it can generate and sell the electricity for more money. I was always in awe of the lake size battery they created.

Maybe this could be applied to water towers? That's a lot of potential energy just sitting there.

Before electricity there were many household appliances that operated on water pressure.

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

#230

Post by jborichevskiy »

Obi_Juan_Kenobi wrote: post #224
jborichevskiy wrote: post #217

Isn't this just transferring energy from the car towing to the Tesla itself? My understanding is this production of power induces some friction, that otherwise would've been closer to neutral. In other words, if the wheels were completely free to spin, would not the towing car require less power to tow? Or is my understanding of this off? Physics was a long time ago

Yes, there's no claim of free energy or perpetual motion here. The author even discusses approximately how efficient the charging is in the video.

Oh yeah I guess I worded it wrong; I wasn't imagining free energy.

Framing it as an efficiency question is more clear, thanks. In other words, this way of converting $natural_resource to Tesla battery level is less efficient than say, plugging into a power grid as there's an extra conversion step (ground to brakes/ambient friction).

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