lolachampcar
Well-Known Member
A 911 BeV will not pull a single (ok, maybe one or two) 911 sale no matter what you call the BeV.
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Porsche Mission E
- Thread starter MartinAustin
- Start date
thegruf
Active Member
Collapse of the entire group is too extreme but I do agree it is serious and in cash terms too from not just fines but loss of sales too, not just book value.
1. A number of R+D projects will get canned - quite possibly something like this
2. VW's rumored F1 takeover of Red Bull Racing must be in doubt, it would be folly to proceed with such a vanity project in light of current circumstances.
3. Likely sell off of some of the additional Marques
4. Possible split at board level maybe fracturing the brands at a core level eg it would be quite conceivable Porsche would split out. There is already history of board level diagreements.
I don't get how 800V, or 2000V for that matter, speeds up charging unless you're willing to replace the battery pretty often. As I understand it, the limit to charging Li ion cells without loosing a lot of battery life is the charge rate, that is how much power per hour are you putting into the cell compared to the cell's power time hours capacity. Power is amps times volts, hours are ... um hours, so if you up the voltage you may charge faster, but at the cost of significant loss of battery life, not to mention the explosion hazard.
Even if the overall battery voltage is 800V, the individual cells are still low voltage, around 2.5V - 4V depending on the chemistry. The difference between 400V and 800V batteries is how many batteries are in series, so while charging each battery sees the same charging voltage no matter how many are in parallel, assuming a good design, and have the same life vs charge rate trade off.
Higher voltages do have lots of advantages for an electric car, but I don't see how faster charging is one of them.
Even if the overall battery voltage is 800V, the individual cells are still low voltage, around 2.5V - 4V depending on the chemistry. The difference between 400V and 800V batteries is how many batteries are in series, so while charging each battery sees the same charging voltage no matter how many are in parallel, assuming a good design, and have the same life vs charge rate trade off.
Higher voltages do have lots of advantages for an electric car, but I don't see how faster charging is one of them.
Higher voltage could translate into faster charging if the cable was the limiting factor.
Every cable has some maximum current it can carry without overheating. Tesla is at 330A already.
One can increase power by upping the voltage or actively removing the heat.
The charger and battery need to be adapted also and I don't see porsche building its own 800v charging network.
Would be nice but no. Double no now VW is doing harakiri...
Every cable has some maximum current it can carry without overheating. Tesla is at 330A already.
One can increase power by upping the voltage or actively removing the heat.
The charger and battery need to be adapted also and I don't see porsche building its own 800v charging network.
Would be nice but no. Double no now VW is doing harakiri...
thegruf
Active Member
what about how many "C" you can charge the battery at?
That's not going to change (unless cell technology does .. and there are some signs of progress).
Doulble the volts/halve the current by all means, you get thinner wire and greater issues with insulation breakdown, but it all evens out when it comes down to the cells
(didnt read enough upthread - RDoc raises the same point)
btw Porsche convenienty didnt say how much it was going to cost (or did I miss that too!).
In tiny volumes expect a Porsche BEV will be stratospheric cost ... or a loss leader ... a right now the VAG group probably not going to back a loss leader.
That's not going to change (unless cell technology does .. and there are some signs of progress).
Doulble the volts/halve the current by all means, you get thinner wire and greater issues with insulation breakdown, but it all evens out when it comes down to the cells
(didnt read enough upthread - RDoc raises the same point)
btw Porsche convenienty didnt say how much it was going to cost (or did I miss that too!).
In tiny volumes expect a Porsche BEV will be stratospheric cost ... or a loss leader ... a right now the VAG group probably not going to back a loss leader.
AustinPowers
Total Smeghead
At first I thought similar, but realistically, I think the following scenario seems more likely:
1. VW has already admitted to the accusations and is working together with the relevant authorities to help remedy the situation. Hence the penalty they will have to pay will most likely be somewhere between one and two billion dollars at the most.
2. That amount of money is nowhere near as collapse-threatening as the 18+ billion max that are floating around.
3. Therefor I don't think they will cut back on any of the projects they are currently planning - except for that huge "clean Diesel" marketing campaign there were just launching in the US (and which they have immediately scrapped. Money down the drain again, but also not life-threatening in the grand scheme of things)
4. They will certainly not sell off any marques. Why should they anyway? If they did, it would have to be one that is losing them money and afaik all of the VW marques (except Bugatti - which they keep for image reasons alone, no matter the cost) are making a profit.
5. And that F1 takeover as you said is just a rumor. I can't see Audi doing away with their extremely successful Endurance series and DTM teams in favor of something as risky and uncertain as being an F1 motor supplier (it wouldn't be anything more anyway. Hardly as glamorous as having your own winning company teams/drivers/cars in those other series I mentioned.)
The only big problem I can see is the worsening image, which in contrast to over here doesn't seem to be the best in the US to start with anyway.
And as for Porsche (or Audi or any other German manufacturer) building their own charging infrastructure: NO WAY!
Let me explain, because you might not know how the German car manufacturers work and think in that respect:
They expect the state (any state) to build a charging network capable off supporting their BEVs. Hell, even the hideously expensive designer charging station in front of the BMW world in Munich was payed for by the German taxpayer, not BMW! (As was, incidently, the incentive program to buy BEVs as commuter cars for Daimler Benz workers. Of course they bought Daimler Benz cars, but not for Daimler Benz money, no, taxpayers' money!)
That is how things work in Germany. So I predict the chances for charging stations built by the car companies themselves are: ZERO
Then again, I didn't hear anything yet about Renault or Nissan having built a charging network for their cars either. Is there such a thing at all?
Tesla really seems to be the only company to have seen the light in the importance of a good charging network for their customers.
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With increasing battery capacities and chemistries the charging speed limitation may not lie in the car battery, but rather in cabling, the charger and it's infrastructure. Heat losses scale with I^2 * R, so for a given power level doubling the voltage will quarter the heat losses. For the same reason it's also more efficient to run electric motors and power electronics at higher voltages.
Except that higher voltages demand stronger (i.e. thicker) insulation. One quickly crosses over into diminishing returns.
There is a sweet spot, as it looks now it is around 400V for many different reasons, including self fulfilling prophecy of installed number of DC charging stations.
I would argue people are slightly too keen to suggest Tesla's choices as the sweet spot on TMC. Not just on this topic, but on things like battery size etc.
Just as Tesla was/is disruptive, at some point some other guy will come out with a silly-sounding idea that will actually work and be better than what Tesla had chosen. It is inevitable. And good.
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There is a lot to like in this Porsche concept but one thing that baffles me is, they do get in wording the idea that EVs offer a clean slate to build on - they even mention lack of center tunnel - and then they go ahead and build a gigantic tunnel in the middle of the car anyway.
I get it that in the front it may even be useful for controls and there technology packed underneath, but why the rear too? Opening up the rear like Model S is in my opinion one real benefit of EVs that allows for greater leg movement for rear passengers, even when there are just two of them. I think Porsche are still lost a little in that ICE mindset there or afraid their customers are... Of course, Tesla took things too far in the Model S by replacing all useful containers with empty space.
How does that explain Chademo, CCS voltages?
And battery voltage of *every* EV and hybrid out there?
Not a single case of battery above 500V.
I wouldn't use current products as a measurement stick of a future sweet-spot any more than I would use EVs of ten years ago as a measurement on what the BEV can be. Nothing wrong with being skeptical about Porsche's vaporware - but to suggest they couldn't be onto something by significantly pushing the envelope of voltage used... that seems almost Luddite to me. I say, bring on the 800V! If they can make it work and make it useful, more power to them.
I am noting a tendency here to be so smitten with Tesla that their choices automatically seem like the sweet-spot. Same could be said of Apple forums some years ago when Apple had gained their current prominence and started to slow down their rate of innovation, churn out safe money from sticking to the formula and others surpassed them in innovation. The usual claim was that Apple no longer needed innovation because they had found the sweet-spot. The disruptor of one day is next day's mainstream. So it goes.
This will happen to Tesla too, one day, if we are lucky. They will mature and others will be more disruptive at times. Then Tesla will hopefully go onto disrupting again, but there will be other disruptors too. This is good. We want some company to disprove the notion that 400V and 90 kW packs and 5% annual improvement is the norm. We want someone who can do 800V and a sweet-spot of 200 kW battery or whatever.
Sure, we can doubt them as long as they are paper tigers, but we should be open to the possibility of taking them seriously. There was a time when a lot of people doubted Tesla too.
Commercial vehicles such as hybrid and electric buses frequently use 600 VDC nominal batteries, with max voltage of 750-800 V during regen charging. Porsche is now going this direction. Higher voltage requires more expensive 1200 V rated IGBTs, instead of the 600 V IGBTs or FETs used by 400 V max passenger cars. Higher voltage not only makes better marketing (800 > 400), but also allows smaller, lighter, and less expensive conductors for a given power level. I am not a motor expert, but IIRC higher voltage can help motors run more efficiently at high speeds, where the back EMF is high. I think this is a good choice for Porsche, as they always are striving to increase the power to weight ratio of their cars.
GSP
PS. Even the lowly Toyota Prius boosts their 200 V battery to 600 V for the inverters and motors, to reduce weight and cost.
AustinPowers
Total Smeghead
Until Porsche has at least several 800V charging stations out there, I'm calling it FUD.
Why is so hard to distinguish between being "Tesla obsessed" and weighting the pros and cons of proposals?
800V charging as is now presented is pure PRBS.
It takes one simple word to take Porsche and 800V story seriously: +150kWh battery with a named source.
Anything smaller (or no source) and all those minutes, %, kms etc is nothing.
Porsche just ain't that guy, sorry.
I want to reiterate that, for me, it isn't that the 800 volt system might not make sense or is particularly difficult at some point. It is that it going to a 800 volt pack voltage doesn't change charge times at all, which was implied by Porsche. Getting a bigger sized pack and/or increasing the charge c-rate tolerance is what gets faster charge times. They will need two generations of battery improvements in order to build a sports car with a sufficiently large sized battery pack with low enough weight and high enough c-rate to get that kind of charge rates. Given how slow battery improvements have come, it's more than a bit silly to talk about delivering a vehicle even in 2019. Then again, it is Volkswagen Group so who knows by what "truth in engineering" they are using here.
The difference with the Model 3 is that Tesla could use the 2013 NCA cells they have been getting from Panasonic and just figure out how to make them cheaper to deliver the Model 3. No fundamental battery technology breakthroughs necessary, just supply chain management. Now, it is likely that Tesla will improve both in specific energy and in cost to deliver the Model 3. Porsche can't deliver that vehicle without fundamental battery research breakthroughs as well as cost to a bigger degree since they are coming from a much higher cost point.
The difference with the Model 3 is that Tesla could use the 2013 NCA cells they have been getting from Panasonic and just figure out how to make them cheaper to deliver the Model 3. No fundamental battery technology breakthroughs necessary, just supply chain management. Now, it is likely that Tesla will improve both in specific energy and in cost to deliver the Model 3. Porsche can't deliver that vehicle without fundamental battery research breakthroughs as well as cost to a bigger degree since they are coming from a much higher cost point.
Thanks. Nice correction. I agree.
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I'm not talking just Porsche but also Audi. I don't know if Audi will have the vision to design a charging network. My comment was that they have both the financial and engineering resources to execute should they decide to do it.
Selling well for Porsche is a much smaller number than selling well for GM. All 918's made were sold and sold at a very high price. I could see the car selling in the tens of thousands even if priced at $200K.
You sound sensitive and defensive. My comment was that the superior powertrain of the Model S has covered up for other issues. As other manufacturers offer competitive powertrains, Tesla will have to become more competitive in areas like interior design and fit and finish. I am saying I think Porsche has the engineering expertise to make a fully competitive powertrain should they decide to do so. As for cannibalizing their other cars Tesla has already shown that an electric drivetrain can have exceptional performance. The top cars from both Porsche and Ferrari employ hybrid drivetrains for performance reasons. Change is underway. In 5 years, Tesla won't be the only game in town. This will be a good thing for the consumer but will put more pressure on Tesla. Yeah, I want coat hooks, some better storage, and decent cup holders. I also want voice commands that compete at least with Hyundai. It does look like cooled seats are coming. Oh yeah, how about better iPod controls. Oops, I left out an aux input jack so my kids can play through the sound system without killing hands free use of my phone. These are all things to be had on a $40K car. Unfortunately you get a lousy ICE drivetrain. Right now the powertrain superiority makes it easy to forgive these things. In the future I expect powertrains from other vendors to be more competitive.
Certainly that's true, I just am very doubtful that the cable is the limiting factor since Superchargers start tapering the charge rate pretty quickly. If the battery could take a significantly faster charge and the cable were the limiting factor I'd think the taper would be much later.
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