An 800VDC battery can still be ~80kWh, like we're figuring this Porsche will have. Getting it charged up to ~80% in 15 minutes could take need to have ~350A or more pumped to it. That's why I'm saying the new IEC standard for 1000VDC @ 400A seems more plausible. 800V@250A isn't going to cut it for their goals.
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Porsche Mission E
- Thread starter MartinAustin
- Start date
An 800VDC battery can still be ~80kWh, like we're figuring this Porsche will have. Getting it charged up to ~80% in 15 minutes could take need to have ~350A or more pumped to it. That's why I'm saying the new IEC standard for 1000VDC @ 400A seems more plausible. 800V@250A isn't going to cut it for their goals.
brucet999
Active Member
So, you're saying that it should take the same time to re-charge a single cell as to charge an entire Tesla battery pack? The only way to decrease charging time is to alter cell chemistry to enable a higher C rate?
allanhof
Member
Thoughts about Porsche Mission E
Beautiful car no doubt. Fact is it is still years away and will likely be far more expensive than a Tesla model S. It was humourous when it was stated it will be better than a tesla. Well sure if you have a few more years to release the mission E a lot of cars will get better! Perhaps Model S will have a next generation release by the time the Porsche is released. And how exactly will they charge in 15 minutes ? Will they build out their own infrastructure to enable this? I think it's a fantastic next step toward a sustainable future but a likely $200k price tag and at that point a 7-8 year lead may not make a dent in Tesla's future other than to potentially stall current buyers from making a purchase decision .
Beautiful car no doubt. Fact is it is still years away and will likely be far more expensive than a Tesla model S. It was humourous when it was stated it will be better than a tesla. Well sure if you have a few more years to release the mission E a lot of cars will get better! Perhaps Model S will have a next generation release by the time the Porsche is released. And how exactly will they charge in 15 minutes ? Will they build out their own infrastructure to enable this? I think it's a fantastic next step toward a sustainable future but a likely $200k price tag and at that point a 7-8 year lead may not make a dent in Tesla's future other than to potentially stall current buyers from making a purchase decision .
phigment
Member
Yes, that that's the key. The 70 and 90kWh battery packs in the Model S (and X?) have a higher amperage cell, but it takes them roughly the same time to charge as their 60 and 85kWh counterparts. Same number of cells, higher amps, slightly lower charge times.
stopcrazypp
Well-Known Member
The C-rate will not change. You are still pumping the same amount of power into each cell no matter how you configure the series/parallel layout of the pack. What the 800V allows them to do is to get around charging cable/connector limitations, which are largely limited by current. I suspect the 5-10 minute charging Straubel talked about will require this (otherwise it'll require something weird like dual cables or something even more thick than current cables).
However, as others noted, parts that are rated for 800V are a lot more expensive. Also, a lot of motors are naturally well suited for 300-400V operation (which is why this voltage range is what practically all production EVs use today). It'll certainly bring its own challenges.
However, as others noted, parts that are rated for 800V are a lot more expensive. Also, a lot of motors are naturally well suited for 300-400V operation (which is why this voltage range is what practically all production EVs use today). It'll certainly bring its own challenges.
Regarding charging, C rate, etc, I'm reminded of the brainteaser:
"If it takes 5 machines 5 days to make 5 widgets, how long does it take 10 machines to make 10 widgets?"
The correct answer is, of course, 5 days... but your intuition will probably have you say 10 days first.
It's the same situation with the C rate, as everyone says. You can't charge any faster without changing the chemistry, and if you (Porsche) can change the chemistry, well guess what? The Gigafactory can change chemistry too.
So Porsche has announced a car that is in almost all respects worse than the currently existing top-of-the-line Tesla. And the only single advantage quoted for it is probably technically incorrect! In the sense that if they are projecting new chemistry, they are comparing future apples to current apples, whereas the future Tesla apples will probably be just as fast or faster, as JB has already projected. (When I say apples, I mean fruit, not Apple cars... which will of course be far superior.)
I figured out that the best way for Tesla to make use of the 800V charging stations is to drive in two of them, and plug them in in series. You'll get both of them charged in the same time as it used to take you to charge just one of them! ;-)
"If it takes 5 machines 5 days to make 5 widgets, how long does it take 10 machines to make 10 widgets?"
The correct answer is, of course, 5 days... but your intuition will probably have you say 10 days first.
It's the same situation with the C rate, as everyone says. You can't charge any faster without changing the chemistry, and if you (Porsche) can change the chemistry, well guess what? The Gigafactory can change chemistry too.
So Porsche has announced a car that is in almost all respects worse than the currently existing top-of-the-line Tesla. And the only single advantage quoted for it is probably technically incorrect! In the sense that if they are projecting new chemistry, they are comparing future apples to current apples, whereas the future Tesla apples will probably be just as fast or faster, as JB has already projected. (When I say apples, I mean fruit, not Apple cars... which will of course be far superior.)
I figured out that the best way for Tesla to make use of the 800V charging stations is to drive in two of them, and plug them in in series. You'll get both of them charged in the same time as it used to take you to charge just one of them! ;-)
jgs
Active Member
Back to the charging network topic –
While I generally agree that the Germans seem to be missing the forest for the trees when it comes to the importance of a charging network, I don't necessarily see it for this particular car (if we can refer to a render of what someone thinks the car might look like if they decide to build it at some point in the future a "car" with a straight face). That's because it's difficult for me to imagine buying one of these as a road trip car, I imagine the more common use case would be to use it within range of home, and own a different vehicle (a Model S?) for road trips.
That said, I've never owned a sports car, it's always been sedans (or sedan-like objects such as the Model S). Is it actually at all usual to road trip with a car like this? I certainly don't see them on rural interstates very often, compared to around big cities. I know I've seen comments from Roadster owners on these forums remarking of that they aren't very upset about lack of Supercharger access because it's not fun to be in the car for long freeway hours anyway.
While I generally agree that the Germans seem to be missing the forest for the trees when it comes to the importance of a charging network, I don't necessarily see it for this particular car (if we can refer to a render of what someone thinks the car might look like if they decide to build it at some point in the future a "car" with a straight face). That's because it's difficult for me to imagine buying one of these as a road trip car, I imagine the more common use case would be to use it within range of home, and own a different vehicle (a Model S?) for road trips.
That said, I've never owned a sports car, it's always been sedans (or sedan-like objects such as the Model S). Is it actually at all usual to road trip with a car like this? I certainly don't see them on rural interstates very often, compared to around big cities. I know I've seen comments from Roadster owners on these forums remarking of that they aren't very upset about lack of Supercharger access because it's not fun to be in the car for long freeway hours anyway.
stopcrazypp
Well-Known Member
There's another far bigger problem that hiroshiy pointed out at the other thread: the current CHAdeMO and CCS spec (and thus chargers) only support up to 500V. That means this car would not be able to charge at existing CHAdeMO / CCS stations without needing some kind of DC-DC converter. And it will not be something like the CHAdeMO adapter (which only needs to translate the communications channel), it actually has to do high power conversion.
http://www.teslamotorsclub.com/show...m-(250miles)?p=1151836&viewfull=1#post1151836
http://www.teslamotorsclub.com/show...m-(250miles)?p=1151836&viewfull=1#post1151836
The issue with charging is not going to be with the batteries - it's going to be the grid. Tesla has said before that it believes that we could see supercharger times cut in half to a third in the next few years and that the batteries would likely be able to take that. The issue is going to be provisioning for 350-400 kW per two parking spaces. Just 10 parking spaces would take up ~2 MW of power at full load - something we give to entire data centers right now.
Three to four years is plenty time for Porsche & others to take up the new CCS standard required to deliver higher voltage / current.
Three to four years is plenty time for Porsche & others to take up the new CCS standard required to deliver higher voltage / current.
This is where the large grid batteries come in. The goal was to have these in places where it makes sense at Supercharger sites.
Porsche annnounces BEV version of 911 - "Mission E"
in my experience a Porsche 911 type of car can certainly be used for long distance trips for people who don't have kids and pets. It is very comfortable and has decent space for luggage for two. The Roadster is a much more bare bones sort of car with a tiny trunk: even if it could Supercharge most people would not use it for long distance travel. But of course some would.
I agree that the jump to 800V is primarily about reducing amperage on the charging end of things in order to allow the required power flow needed to charge the pack as quickly as they're intending without requiring impractically thick cables and unwieldy connectors. On the drivetrain end of things, though, there's no reason they can't continue to run a 400V system: what if the battery is actually two 400V packs that will normally be switched into a parallel configuration (via contactors) running at 400V and then can be switched into a series configuration to convert the pack to 800V when needed for HVDC charging?
stopcrazypp
Well-Known Member
I thought of that possibility too, but didn't really mention it. That would be a way to do it without needing DC-DC conversion and they can have it as a mode that can support existing CHAdeMO/CCS charging.
Candleflame
Active Member
porsche has a history of some adventureous EV designs (Tiger Tank anyone?), but this actually has to "work" in real life and not cost a few million...
davidc18
Active Member
Mission (impossibl) E: I see no Tesla Killer anywhere on the horizon!
According to Fortune "The 600-horsepower vehicle will be able to reach 100 kilometers per hour (62 mph) in 3.5 seconds, beating the 4.2 seconds of the newest generation Porsche 911. It’s expected to reach the market within five years.
Matthias Mueller, head of the Volkswagen AG unit, said that this concept is “better than a Tesla.” Its battery charges to 80% in 15 minutes, half the time it takes a Tesla vehicle to charge. The Mission E will also have a range of 500 kilometers as compared to Tesla’s 434km (270 miles)."
They are comparing a yet to be built "concept" sports car to the 2012 Model S 7 passenger sedan. The P90DL would blow the Mission E away and my 2012 P85 Sig would give it a run for a lot less money. The P90DL Model S has a range of 300 miles and hits 60 in 2.8 seconds. So Tesla is even further ahead in the EV race than the 5 years I previously thought. The new Tesla Roadster is really what they should be comparing but of course we have no specs on that yet. Nonetheless, it is not hard to imagine that Tesla's super car will be light years ahead once it does come to market! I see no Tesla killers for a very long time to come.
According to Fortune "The 600-horsepower vehicle will be able to reach 100 kilometers per hour (62 mph) in 3.5 seconds, beating the 4.2 seconds of the newest generation Porsche 911. It’s expected to reach the market within five years.
Matthias Mueller, head of the Volkswagen AG unit, said that this concept is “better than a Tesla.” Its battery charges to 80% in 15 minutes, half the time it takes a Tesla vehicle to charge. The Mission E will also have a range of 500 kilometers as compared to Tesla’s 434km (270 miles)."
They are comparing a yet to be built "concept" sports car to the 2012 Model S 7 passenger sedan. The P90DL would blow the Mission E away and my 2012 P85 Sig would give it a run for a lot less money. The P90DL Model S has a range of 300 miles and hits 60 in 2.8 seconds. So Tesla is even further ahead in the EV race than the 5 years I previously thought. The new Tesla Roadster is really what they should be comparing but of course we have no specs on that yet. Nonetheless, it is not hard to imagine that Tesla's super car will be light years ahead once it does come to market! I see no Tesla killers for a very long time to come.
RobStark
Well-Known Member
Mission E is not a Roadster but a 4 door coupe. Either compact or midsize.
The most direct Tesla competitor would be the Performance version of the 2018 Model 3 liftback sedan.
My guess M3 P90D will outperform Mission E and undercut the price as well with a far superior Fast Charging Network.
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