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Tesla owner drives 452 miles on single charge

techcrunch.com

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Re: Tesla owner drives 452 miles on single charge

#51

Post by feld »

feld wrote: post #50
nixarn wrote: post #45

Earlier quoted context omitted.

As I posted on the other thread (that didn't seem to get a lot of attention), the range is actually worse on the P85D (270 miles on the P85 and 253 miles on the P85D),

The P85D is rated at 295 miles. I don't know where you're getting 253 at. The P85 is 275.

edit: ugh, this is weird. Even their site lists different ranges per car and they've added a calculator to estimate range based on speed, temperature, and whether or not you're running AC.

I guess the "rated range" is full of holes.

Re: Tesla owner drives 452 miles on single charge

#52

Post by brandon272 »

feld wrote: post #3

I commented in another similar post but it seems to be lost... My friend did 438 miles with his P85 by drafting behind a semi the entire trip. With the extra range (efficiency!) of the P85D I'm certain he could have hit 500, easy. I don't recall how many Wh/mile he was doing but it was crazy low. I'm not sure why he hasn't been contacted about his drive, but Tesla does have the data and he's asked a couple engineers…

Isn't that just asking for rocks in your hood?

Re: Tesla owner drives 452 miles on single charge

#53

Post by pc86 »

LoSboccacc wrote: post #44
eridius wrote: post #36

Earlier quoted context omitted.

But can't they also talk to each other over CB radio? Seems like that would make it safer. And of course it's a lot easier to see a truck right behind you than it is to see a car.

Still they block the exits for cars that need to merge. Happened once to me, a train of ten trucks slipstreaming right when I needed to take an exit. Couldn't slow down and merge at the end and the head was already after the exit. Had to match carefully speed and merge the car in a space I wouldn't have used for parking. And the asshole even blew the horn at me! Seriously, fuck those idiots doing it. Driven for years…

> Had to match carefully speed and merge the car in a space I wouldn't have used for parking.

> needing to save those ...five minutes

So you wouldn't have parked there but you have no problem squeezing between two moving objects 10x your weight/inertia at highway speed? All so you can take an exit (that you were inexplicably in the left lane when you realized you needed it) rather than just take an extra five minutes and turn around at the next exit?

Hard to imagine why he blew his horn.

Re: Tesla owner drives 452 miles on single charge

#54

Post by tempestn »

hkmurakami wrote: post #2

The (imo, more interesting) stats in the video are missing from the article text body: Total Distance: 728.7km, 452.8mi Total Energy: 77.5kWh Average Energy: 106Wh/km, 171Wh/mi Driving Time: 18:40 hours Average Driving Speed: 39.0km/h, 24.2mph Total Stops: 1 hour Total Time: 19:40 hours Max Elevation: 94m, 310ft

Given those stats, his average power usage was 4.1kW, or about 5.5HP. Not bad considering that's input power including all peripherals and losses, not just power to the wheels.

Re: Tesla owner drives 452 miles on single charge

#55

Post by kwhitefoot »

tempestn wrote: post #54
hkmurakami wrote: post #2

The (imo, more interesting) stats in the video are missing from the article text body: Total Distance: 728.7km, 452.8mi Total Energy: 77.5kWh Average Energy: 106Wh/km, 171Wh/mi Driving Time: 18:40 hours Average Driving Speed: 39.0km/h, 24.2mph Total Stops: 1 hour Total Time: 19:40 hours Max Elevation: 94m, 310ft

Given those stats, his average power usage was 4.1kW, or about 5.5HP. Not bad considering that's input power including all peripherals and losses, not just power to the wheels.

This is about 20% less than the rule of thumb number for the power needed to keep a modern mid size car moving at about 100km per hour. I forget where I read it.

So yes pretty good.

And this is the principal reason why internal combustion engines are so inefficient in practice, they are used at a tiny fraction of their rated output for most of their working lives.

Of course the comparison is not quite as favourable as it at first appears because we should really measure the input power not at the output of the battery but at the input of the battery charger (equivalent to measuring the fuel pumped into a petrol engine's tank). Still impressive even if the conversion efficiency of the charger and battery combined is only 50%.

Re: Tesla owner drives 452 miles on single charge

#56

Post by kwhitefoot »

001sky wrote: post #13
dublinben wrote: post #4

Earlier quoted context omitted.

24mph is an excruciatingly slow average speed for a 450 mile journey. No wonder they were able to be so efficient.

so, basically slower than a pro on a bicycle nice one

What would the pro's average speed be over the total distance? And what would an ordinary human being manage?

Re: Tesla owner drives 452 miles on single charge

#57

Post by kwhitefoot »

babo wrote: post #35
ferrari8608 wrote: post #26

Earlier quoted context omitted.

Truck drivers really don't like people driving close enough behind them to be in their slipstream. If you're that close, they can't see you.

They do this themselves, at least in Europe. It's scary like hell that they follow each other, neck by neck, hour by hour with the shortest possible tracking distance.

Less than one second spacing is illegal in Norway and Germany. Three seconds is recommended.

At 90km an hour (maximum speed for lorries) that is 25m, about four times the length of my car. Is that close enough to get any useful effect?

Re: Tesla owner drives 452 miles on single charge

#58

Post by kwhitefoot »

pc86 wrote: post #53
LoSboccacc wrote: post #44

Earlier quoted context omitted.

Still they block the exits for cars that need to merge. Happened once to me, a train of ten trucks slipstreaming right when I needed to take an exit. Couldn't slow down and merge at the end and the head was already after the exit. Had to match carefully speed and merge the car in a space I wouldn't have used for parking. And the asshole even blew the horn at me! Seriously, fuck those idiots doing it. Driven for years…

> Had to match carefully speed and merge the car in a space I wouldn't have used for parking. > needing to save those ...five minutes So you wouldn't have parked there but you have no problem squeezing between two moving objects 10x your weight/inertia at highway speed? All so you can take an exit (that you were inexplicably in the left lane when you realized you needed it) rather than just take an extra five minutes…

The lorry driver was in the wrong he was driving with an illegally small space between him and the vehicle in front.

Re: Tesla owner drives 452 miles on single charge

#59

Post by tempestn »

kwhitefoot wrote: post #55
tempestn wrote: post #54

Earlier quoted context omitted.

Given those stats, his average power usage was 4.1kW, or about 5.5HP. Not bad considering that's input power including all peripherals and losses, not just power to the wheels.

This is about 20% less than the rule of thumb number for the power needed to keep a modern mid size car moving at about 100km per hour. I forget where I read it. So yes pretty good. And this is the principal reason why internal combustion engines are so inefficient in practice, they are used at a tiny fraction of their rated output for most of their working lives. Of course the comparison is not quite as favourable a…

Cool, do you have a source for that rule of thumb? That's a new one for me. That's about 8HP to the wheels to keep it rolling at 100km/h right? So obviously more than that from the engine.

Re: measuring at battery input rather than output, that's a good point. Would definitely be higher that 50% charging efficiency though. I would guess at least 80% - probably > 90% if you charge it slowly enough. (Haven't done any research on Tesla chargers or batteries specifically, but I did used to be a power electronics engineer. High charging efficiency is important both for cost and, perhaps as importantly, because a slight reduction in efficiency can mean a lot of extra heat that you have to deal with.)

Re: Tesla owner drives 452 miles on single charge

#60

Post by kwhitefoot »

tempestn wrote: post #59
kwhitefoot wrote: post #55

Earlier quoted context omitted.

This is about 20% less than the rule of thumb number for the power needed to keep a modern mid size car moving at about 100km per hour. I forget where I read it. So yes pretty good. And this is the principal reason why internal combustion engines are so inefficient in practice, they are used at a tiny fraction of their rated output for most of their working lives. Of course the comparison is not quite as favourable a…

Cool, do you have a source for that rule of thumb? That's a new one for me. That's about 8HP to the wheels to keep it rolling at 100km/h right? So obviously more than that from the engine. Re: measuring at battery input rather than output, that's a good point. Would definitely be higher that 50% charging efficiency though. I would guess at least 80% - probably > 90% if you charge it slowly enough. (Haven't done any r…

Alas i can't remember and a quick web search doesn't find anything I recognize. But I did find this that mentions 10hp at 50mph: http://energy.typepad.com/the-energy-blog/2010/02/energy-nee... And a few hotrodders discussing the question here: http://www.hotrodders.com/forum/how-much-hp-required-60mph-1... This on PhysicsForums: https://www.physicsforums.com/threads/power-and-tq-needed-to...

And finally a paper with real formulas and better explanations: http://wps.aw.com/wps/media/objects/877/898586/topics/topic0...

Looks like my 5kW wasn't too far off.

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