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Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

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Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#231

Post by madaxe_again »

davidwhodge wrote: post #92
steelframe wrote: post #18

I've been following a multi-month discussion over in the r/electricvehicles subreddit about EPA range. There's a growing consensus that something is very wrong with it. Here are a couple of the articles that got some discussion in that sub: https://insideevs.com/news/407807/eletric-car-real-world-ran... https://www.caranddriver.com/reviews/a30874032/porsche-tayca... As someone who has owned both a Tesla Model X and o…

I make an app (called Nikola, not the truck company) for Tesla owners that has seen over 5 MM miles driven on it. I did some quick queries to validate actual range vs. EPA range for those curious. My general takeaway is to see the EPA range as a useful, albeit unrealistic, indicator. Essentially nobody gets the EPA range, either because they choose not to go the speed limit, they accelerate harder than the EPA test f…

Air, rolling and other mechanical resistances are certainly part of the equation here, but the major driver of the decreased range at higher speeds is likely battery chemistry.

When you apply a load to a cell, the voltage sags. Heavier load, bigger sag. When a battery is operated at low voltage, it loses efficiency - the total power available decreases significantly. If you ever buy batteries for, say, building your own EV, you’ll pay a lot of attention to the C values - C1 is the capacity of the cell if it is discharged in 1 hour, C100 is the capacity at 100 hours, etc. - and there is a big difference between these values - it’s non-linear, and while the difference between C100 and C10 might be a 30% loss of available power, between C1 and C10 you’re closer to 50% - a 65% loss overall between C100 and C1.

Obviously in an EV C2-C10 are probably your most relevant numbers - but the difference in available power is significant over that range, and if you’re driving harder, putting more load on the battery, your range will be lower.

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#232

Post by londons_explore »

baddox wrote: post #230
ajuc wrote: post #207

Earlier quoted context omitted.

Additionally if you drive 10% faster you spend ~9% less time on the trip which means heating/AC is working 9% less.

And there’s also some “inherent” value in spending less time traveling that is more difficult to quantify.

To balance with the inherent disadvantages of more speeding tickets and a higher risk of a collision.

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#233

Post by londons_explore »

sxp wrote: post #134
davidwhodge wrote: post #92

Earlier quoted context omitted.

I make an app (called Nikola, not the truck company) for Tesla owners that has seen over 5 MM miles driven on it. I did some quick queries to validate actual range vs. EPA range for those curious. My general takeaway is to see the EPA range as a useful, albeit unrealistic, indicator. Essentially nobody gets the EPA range, either because they choose not to go the speed limit, they accelerate harder than the EPA test f…

> What's most striking to me as someone who has heard over and over again about how air resistance is a X^2 property, is the extent to which short (and presumably slow) trips punch above their weight in terms of range consumed per mile. From what I can tell, the actual cost here is the fixed cost of booting up some systems and electronics, and the variable costs of running them over fewer miles can make the MPGe drop…

I think there's a good chance the energy used while parked is greater than the dashboard suggests (measuring power remaining in a lithium battery is hard!). Then when you start driving, the estimate gets more accurate, and the range disappears over the next 15 minutes or so.

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#234

Post by arethuza »

octorian wrote: post #216
rossjudson wrote: post #181

Earlier quoted context omitted.

"Nobody is going to buy this thing. I commute 250 miles each way to my job, in my pickup truck. Call me back when Tesla makes a real car with real range. Anybody who buys these now is a sucker." Because people keep saying shit like that. Tesla's range increases are a giant experiment to find out at exactly what point opposition to electric collapses.

"Nobody is going to buy this thing. I commute 250 miles each way to my job, in my pickup truck, hauling a load of lumber to a cabin 100 miles from civilization. There's no electricity out there. Call me back when Tesla makes a real car with real range. Anybody who buys these now is a sucker." FTFY. There's one of these in EVERY discussion of something Tesla releases :-)

To make your day I will add a post like that.

A typical weekend for me involves driving ~150 miles to leave my car in the cold and wet in the middle of nowhere for 8 to 9 hours while I wander around some mountains. Only 2 superchargers in the country and their not between where I live and where I go.

Is this unusual - absolutely (mind you plenty people here do similar things) - but range is an important factor to me. However, the main one is cost - absolutely no way will I spend more than £25K on a car.

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#235

Post by londons_explore »

alvah wrote: post #143
sgc wrote: post #46

Earlier quoted context omitted.

For ICE cars, it depends on what the mfg has optimized for. I had an Infinity years ago and I remember that it was optimized for 70mph precisely as per the owner's manual. Higher or lower speeds would be less efficient.

Interesting(ish) tangent - the UK fuel economy specs used to be published at a constant 56mph & 75mph. When the Mk3 Vauxhall Cavalier was launched in the late 1980s, it had great (theoretical) fuel economy, much better than its rivals, but a couple of noticeable flat spots under acceleration. Turned out Vauxhall had leaned the fuel maps at the exact engine revs that corresponded to 56mph and 75mph in top gear...

Defeat device...? Cheating...? Multi-billion pound fine?

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#236

Post by jacobush »

rossjudson wrote: post #181
leesec wrote: post #122

Man do I love Hackernews. Everyone is pro-innovation, pro-future, pro-forward thinking until literally anything new happens, in which case everyone shows up with a "well, ackshually", to tell you why the new idea is dumb. It's amazing to me that Tesla continues to increase State Of The Art range and EV efficiency, at scale, for cars that already smoke the competition. I hope their fervor to improve the technology nev…

"Nobody is going to buy this thing. I commute 250 miles each way to my job, in my pickup truck. Call me back when Tesla makes a real car with real range. Anybody who buys these now is a sucker." Because people keep saying shit like that. Tesla's range increases are a giant experiment to find out at exactly what point opposition to electric collapses.

For me it has always been at a range of 1000 kilometers. (600 miles.)

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#237

Post by londons_explore »

sgc wrote: post #46
walrus01 wrote: post #41

Earlier quoted context omitted.

I can duplicate pretty much the same effect with cruise control in my gasoline powered car. If I go on a 5 hour freeway road trip with cruise at 65mph and spend 95% of my time in the right lane, there's definitely a 2-3 mpg improvement in fuel consumption, vs 75 mph. At that point it becomes a tradeoff in time vs money spent on extra fuel, and need to get somewhere in a hurry. Over a 4.5 hour period if I can cruise a…

For ICE cars, it depends on what the mfg has optimized for. I had an Infinity years ago and I remember that it was optimized for 70mph precisely as per the owner's manual. Higher or lower speeds would be less efficient.

If you really really care about miles per gallon, nearly any ICE car the most efficient way to drive is at or near idle in top gear, going about 25 mph. The difference is remarkable - a car which usually gets 50 mpg can easily get 100mpg with that approach, although obviously you can't practically drive like that on the public highway.

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#238

Post by allendoerfer »

elihu wrote: post #84
sgc wrote: post #51

Earlier quoted context omitted.

yes and no. Older cars were far heavier and far less safe. They could make incremental safety design improvements that allow to reduce weight incrementally without compromise.

I think cars of all eras have had a mix of heavy and light designs. With modern materials, it's possible to make safer, lighter cars but modern cars are also required to have more safety features. A Model S is about 4500 to 5000 pounds. I used to drive around in a 1981 Mazda GLC, which is about 1800 pounds. The White Zombie, a famous electric conversion with a 0-60 time of about 1.8 seconds is based on a 70's Datsun…

Next to roads are often things like bridge pillars and those things are also very heavy and not very soft.

Re: Model S Long Range Plus: Building the First 400-Mile Electric Vehicle

#240

Post by lazyjones »

Someone1234 wrote: post #31
steelframe wrote: post #18

I've been following a multi-month discussion over in the r/electricvehicles subreddit about EPA range. There's a growing consensus that something is very wrong with it. Here are a couple of the articles that got some discussion in that sub: https://insideevs.com/news/407807/eletric-car-real-world-ran... https://www.caranddriver.com/reviews/a30874032/porsche-tayca... As someone who has owned both a Tesla Model X and o…

I'm surprised Tesla fans haven't crowd sourced accurate data by now.

ecalc.ch (https://www.ecalc.ch/evcalc.php) is very accurate in my opinion.
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