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Probable Base Price?????

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Old 07-17-2017, 06:14 PM
  #31  
Lorenfb
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Originally Posted by gnochi View Post
It is a huge voltage drop and a huge power loss, with a correspondingly high cooling requirement. It's a fact of life for high performance EVs (which the Leaf is not by any definition). And why would they ever report that info publically? It's competitive advantage territory.

We tested various discharge rates and states of charge. The cells individually bottom out at about 42mOhm for really low discharge rate, 45mOhm+/-1mOhm for typical discharge rates and 20%-90% SOC, and go as high as 70mOhm at low states of charge.

There are cells with lower impedence, but they universally have lower energy as well, because there's a tradeoff between metal volume (low resistance, no energy) and jelly roll volume (high resistance, high energy).
Your reference/source of Tesla's dynamic battery impedance, please.
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Old 07-17-2017, 10:57 PM
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Originally Posted by Lorenfb View Post
Your reference/source of Tesla's dynamic battery impedance, please.
I'm not going to share company proprietary reports and such, even heavily redacted. I personally did the experiments, as did several of my colleagues at 2 companies - who have themselves worked at every company that's publicly announced an EV product - and those were the numbers we were seeing.

If you have a non-proprietary source that says otherwise, of course, please feel free to share, but I stand behind my research and my teams.
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Old 07-18-2017, 01:21 PM
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Originally Posted by gnochi View Post
I'm not going to share company proprietary reports and such, even heavily redacted. I personally did the experiments, as did several of my colleagues at 2 companies - who have themselves worked at every company that's publicly announced an EV product - and those were the numbers we were seeing.

If you have a non-proprietary source that says otherwise, of course, please feel free to share, but I stand behind my research and my teams.
Well, if your Tesla data are correct, Tesla's battery technology (Panasonic) compared to Nissan's
could use improvement:

Re - Nissan's effective overall battery impedance
Rs - Nissan's single cell battery impedance

Re = Rs X 96 / 20, where Re = 56 millohms (new @ 30 C)

Rs = Re / 4.8 = ~ 12 mohms

The Leaf's max motor current is about 225 - 250 amps which results in only about
only a 15 volt battery voltage drop compared to the Tesla's voltage drop at 1000 amps
of about 60 volts (poor efficiency).

If these data are accurate, it's time for Elon to use those SpaceX physicists on Tesla's battery technology.
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Old 07-18-2017, 11:24 PM
  #34  
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Originally Posted by Lorenfb View Post
Well, if your Tesla data are correct, Tesla's battery technology (Panasonic) compared to Nissan's
could use improvement:

Re - Nissan's effective overall battery impedance
Rs - Nissan's single cell battery impedance

Re = Rs X 96 / 20, where Re = 56 millohms (new @ 30 C)

Rs = Re / 4.8 = ~ 12 mohms

The Leaf's max motor current is about 225 - 250 amps which results in only about
only a 15 volt battery voltage drop compared to the Tesla's voltage drop at 1000 amps
of about 60 volts (poor efficiency).

If these data are accurate, it's time for Elon to use those SpaceX physicists on Tesla's battery technology.
The Model S packs 4x the energy into about 1.5x the volume, and can deliver 6 times the power. There are tradeoffs, and if you go through the in-depth analysis with real-world cells for the same pack size, the way to get more range (or more power capacity and keep the range) is always to get more energy.

We're getting close to the point at which the additional energy per cell is offset by the increase in resistance and corresponding efficiency drop, but we're not there yet, and there are some new chemistries that may be promising in a few years. In the meantime, though, Sony, LG, Samsung, and Panasonic are all focusing on packing incrementally more energy into the same volume with as little of a resistance hit as possible, because that's what most high-performance and road-trippable EVs demand.

Or, as the shift from 18650 to 21700 occurs, fit 30-50% more energy in 46% more volume at 60% the resistance.
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Old 07-21-2017, 05:59 PM
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Originally Posted by GiuseppeM View Post
I agree, base price $160k
I don't see how 20,000 move at this price, which leans Panemera. The Germans have employed natual demand limiters in what they electrify. It doesn't look like a small battery, this time. The suicide doors probably ought to go. A lot else to find out, yet.

On the up side, one can imagine Porsche installing several of its 350KW chargers at race tracks. 20 minute DE sessions could use ~40KWh ea, and be topped off in as fast as ~7 minutes.

In the flesh I could see buying this car, but I can't see waiting as the trust level isn't there.
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Old 09-14-2017, 09:51 PM
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Old 09-14-2017, 10:10 PM
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There is hope yet for us plebs.
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Old 09-16-2017, 01:52 PM
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I truly hope the car they build is very faithful to the concept and it meets the performance claims they're making. If it does, I'm very interested. If it just looks like a Panamera, but with an electric motor, I'll have zero interest.
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Old 09-16-2017, 04:48 PM
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Last edited by asia; 09-30-2017 at 02:30 AM.
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Old 09-17-2017, 12:54 PM
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Originally Posted by Archimedes View Post
I truly hope the car they build is very faithful to the concept and it meets the performance claims they're making. If it does, I'm very interested. If it just looks like a Panamera, but with an electric motor, I'll have zero interest.
Could not agree more. I find the concept stunning and way more appealing to me than a model S but if production time comes and there's a drastic difference I'll be more than a little disappointed
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