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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

#291

Post by drcoopster »

nomel wrote: post #259
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.

My Toyota car, with an automatic transmission, does this automatically after it detects I've been riding the brakes for some time while going down a hill. Coming from manual transmission, I was super excited when it happened the first time.

My 17-year-old Honda minivan does the same. A few seconds on the brakes while going down a steep hill will trigger a downshift.

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

#292

Post by CrazyStat »

8note wrote: post #285
codeismath wrote: post #164

Earlier quoted context omitted.

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…

Extra power at night? Where's it coming from?

Demand is low at night, but many types of power plants are not easily/efficiently throttled down for lower supply (e.g.: nuclear, wind). So it makes sense to use the extra supply to pump water up.

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

#293

Post by Sharlin »

8note wrote: post #285
codeismath wrote: post #164

Earlier quoted context omitted.

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…

Extra power at night? Where's it coming from?

Not extra, excess. Demand is lower at night.

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

#294

Post by mceachen »

8note wrote: post #285
codeismath wrote: post #164

Earlier quoted context omitted.

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…

Extra power at night? Where's it coming from?

At least in the case of https://www.electricmountain.co.uk/Dinorwig-Power-Station it provides near-instantaneous peak power (especially at the top of the hour when everyone turns on their kettle for tea), and is recharged through the early am via nuclear and other power plants that can't be shut down that quickly.

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

#295

Post by martyvis »

femto wrote: post #221
AceJohnny2 wrote: post #196

Earlier quoted context omitted.

> 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, a…

They are only adding 2GW of generation capacity, so I guess the 350GWh stored would take a week (175 hours) to be consumed by Snowy 2.0 that way.

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

#296

Post by beowulfey »

throwawayboise wrote: post #100
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…

What does the equation look like when you subtract the energy used in the actual mining, though?

thats not really a factor because the ore is being mined for other reasons, not strictly to generate power

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

#297

Post by asdff »

bigiain wrote: post #231
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.

Most mechanics will quip "Remember, brake pad replacement is a lot cheaper than a transmission replacement". Don't over do it.

There's no harm in engine braking if you shift correctly and mate your RPMs to the next gear.

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

#298

Post by exporectomy »

cartoonworld wrote: post #220
olyjohn wrote: post #189

Earlier quoted context omitted.

Your front end still takes the weight under any deceleration event. That's why FWD cars still squat in the rear on acceleration.

yes, it will always rock fore and aft to some extent, but consider the difference between applying a drag to the front of the vehicle or the rear. Try this on a bicycle if you have the time. The "squat" you see on accelerating FWD vehicles is something different called wheel climb I think and is related to the effects of braking and center of gravity that we are discussing. When you gun the throttle, the wheel torque…

> If you apply only rear brake, it will cause the rear wheels to pull their suspension downwards tipping the car rearward somewhat.

Are you sure? I'm trying to draw a free body diagram of that, and I get a net moment tipping the car forward. Can you explain it using physics principles?

> Try this on a bicycle if you have the time.

You can't easily compare because the rear wheel easily skids with a fraction of the braking force the front wheel can take.

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

#299

Post by fiddlerwoaroof »

anonporridge wrote: post #267
ryanmarsh wrote: post #243

Earlier quoted context omitted.

The Tesla charger at my residence charges the car at ~30mph

I love this measure of charging speed. I'm wondering now why I haven't ever seen it used before.

This is pretty standard: the Tesla charging screen shows this while charging.

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

#300

Post by rektide »

genewitch wrote: post #197
rektide wrote: post #57

Earlier quoted context omitted.

Seems like a lot of physical infrastructure spread out over a lot of area for little gain. Little gain because it doesn't feel like charging at fixed stations is so bad, and it's not something folks need to do that often. There's other challenges too. You'd also need to build some system for billing, such that people don't start to steal power. Do we trust the cars to meter themselves? Or do we try to have the line m…

Commercial drivers routinely make at least $0.50 per mile... towing hazardous materials (lithium or sulfuric acid and lead) is an endorsement that guarantees more money, as well. Add in amortized cost of the truck, charger, fuel, and batteries, you're looking at a "30 minute charge truck" costing like $25, minimum.

cdl (commercial drivers license) starts at 13 tons. that's way way more battery than I had in mind, multi megawatt-hour class. no. that's be stupid. no one is talking about hazardous materials. they're talking about a vehicle with 2x, 3x, 4x more battery than we have today. which, as battery technology continues to advance, will become probably smaller and lighter.

i appreciate your attempts to check me & my fantasies but wow I really think you are way way way off here, orders of magntiude off target on the emerging economics.

As for your 30 minute charge, at 200kW (a very attainable rate today already) a 30 minute charge is 80kWh, a full charge for most cars. Why do you need a full charge? in my head I see this more as a system of 10 minute charges, that turn back after a certain distance to maimtaon proximity to home. just get more charge from the next township's local charge fleet.

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