daveo4porsche

more thoughts on charging

there is also quite the push where EV chargers are being installed at "shopping" malls - so people can charge their cars while they are doing other activities - a local mall in the San Jose area has 60 Chargepoint EV chargers in the parking garage - electricity is cleaner than gasoline so you can have more places "fill up" with less toxic waste/distribution concerns - they also don't require any attendants…since it's all automated and directly account based billing…

charging time matters a lot less if you aren't standing there waiting for it to be done…

as people adapt to this model the old expectations of filling up in 5-10 minutes melt away and people go about their business charging when they can and no obsessing about being "full"…

for the people that can charge over night at home -it's an ideal usage patterns, other use cases can be made to work and will get easier in the future as demand and supply balance.

the _ONLY_ time it matters how long it takes to "fill up" an EV - is during a road trip - and EV's are still not there in terms of time to charge vs. ICE - but it's not horrible and more than acceptable for the 3-7 road trips a year I take…

ace37

My wife is excited that she won't have to go to gas stations anymore when she gets a Mission E. That's very much seen as an upside, not an issue! Some love the idea of a solar roof - mostly thinking along the lines of I like the principle and the numbers work out well enough.

For road trips we'll continue to take the comfortable family SUV. Even if we had an EV as an only vehicle we could always just rent something for road trips.

daveo4porsche

@ace37 - that's a good plan and I know a lot of people that go into EV's with that plan - driving an ICE for long trips and the EV for other things...

I will state for the record that most EV owners that I hang with become enamored with their EV to such a point that they no longer want to drive the ICE and prefer the EV so much that they do the road trips with EV's even given the difficulties - basically it ruins you for other cars - kinda like Porsches ruin you for other sports cars.

but yeah that plan can work - and my wife loves her EV and never going to the gas station.

928 GT R

gnochi,

What is the total weight reduction of a state of the art EV powertrain vs an ICE powertrain?

Including motor(s), transmissions, differentials, fuel and exhaust systems, batteries and wiring...

Thx!

gnochi

Really interesting discussion on charging, thanks. I think we'll see an emphasis on street-parking chargers in big cities, and it's definitely something I could see paying a bit extra in rent to have ready access to. I also expect we'll see people wanting street-side apartments so they can hang extension cords out the window in the mean time =D

Unfortunately for BEVs, this is not an area they really shine... the battery pack alone weighs over half a ton once you break 80kWh, and gets heavier as you increase the allowable energy content. If we compare the Model S at 4900lb curb weight to the Acura TLX at 3700lb curb weight, almost all of that weight difference is in the battery. The motor is physically smaller and significantly lighter than a typical engine, and the inverter's a few more pounds tacked on to that. Figure 50lb in cables, and all of the accessories now need to run on their own internal motors and such, so they end up weighing a fair bit more.

Short answer, everything but the battery makes it break even on weight, and then add the battery on top of that.

We're still working on tricks to take weight out of the rest of the car, because we suddenly have a massive shear panel on the bottom that provides pretty impressive structural benefits, but it'll be a few more years before we see any real savings here.

daveo4porsche

and even with the weight a P100D can do zero-60 in 2.x seconds (x keeps getting lower with software updates) - picture what they could do if the battery weight comes down.

I agree after driving a Model S for nearly 4 years - it's heavy car, but given instant torque and a lot of it the car is surprising sprite and quicker than most anything on the road...is it hte best sports sedan in existence, probably not - is it better than most sports sedans probably

I pass a lot of "better" sports sedans int he car pool lane every day ;-)

Lorenfb

That we are in agreement on!

daveo4porsche

it's interesting to me that Tesla specifically stated their plan to double superchargers in 2017/2018 was specifically to address the high-density urban "charge 1-2 times a week" use case…and in keep with their install practices they are picking locations like shopping mall parking lots for the install.

Given that even supercharging takes about a hour to "full" (90% normally daily use - it's bad for LiON batteries to be constantly charged to 100%)

people can charge while they do grocery shopping or other weekly activities - if you combine charging with errands it's really not that hard to kill an hour or less while your car charges…

DCFast/Supercharing/Porsche-charging all can nearly fully charge these batteries in an hour or less - which if you don't have access to home charging is not a terrible use model…

Lorenfb

Yes, most can rationalize this. No need to 'preach to the choir'.

928 GT R

It is hard to believe that the Tesla is that much heavier - given the great performance characteristics of the P100D.

Today's battery technology is impressive, but gnochi makes it clear that new (lighter/denser) batteries will create another entire level of market acceptance for EV's. When we have 400 mile range with 15-20 minute charge times and easy access to chargers there will be few (if any) drivers that would not use EV's.

Solid state batteries and/or carbon nano-tube super capacitors could be the answer, but it will probably be something completely new that tears the envelope we now drive within, apart.

Porsche's participation in FIA's Formula E racing circuit is great news because nothing pushes human creativity faster than World Championship racing competition.

I can't wait to see what we will be driving in 2025!

daveo4porsche

the problem with 400 mile range is that's at least 140 kWh battery

delivery of 140 kWh in about 20 minutes is 450,000 watts

at 800 volts that's about 580 amps
at 480 volts that's about 1000 amps

to do that at scale is an electrical challenge

charge time doesn't play a role in EV usage for most of your annual usage - I still think the obsession with charge time gets in the the way of really considering an EV and how often charge time matters (not very often)

+1 on the 400 mile range however

928 GT R

Porsche has always had a talent for pushing the boundaries of "fueling" quicker than the rest of the race teams they compete against. It would not surprise me if they have a capacitor based type of charging system in mind.

I agree that the vast majority of driving and therefore charging is well within the range of conventional home chargers, but, and it forms the backbone of the "obsession with charge time" layer of resistance for EV's. People do want to take "road trips" and travel without several 1/2 to 1 hour charges en route to the destination.

Since VW/Porsche has agreed to spend over $800 million on EV charging stations as part of diesel gate, it is inherent that they will use it to leapfrog Tesla's charging network as they roll out their EV's.

Cutting to the chase, I think that there may be a capacitor type 800 volt - 600 amp charging system being deployed by VW/Porsche in the not so distant future.

With all the things mankind has pushed beyond the "challenges" of the brain I see more quantum leaps coming than perceived "limits" standing in place.

We get to enjoy the ride!

Lorenfb

Calculate the size of the needed capacitor assuming:

1. 100kWh (typical 250 - 300 miles) of needed battery energy (360MJ)
2. Energy = 1/2 C X V^2 (C in farads)
3. V = 800 volts

May have been available at Radio Shack?

daveo4porsche

I'm not worried about the ability to charge a car like that once or twice - I'm worried about cycle time for fast charging - eventually the capacitors will be "empty" and you'll be relegated to the speed of the raw power feed…

I see busy supercharger stations and they have hardly any down time between cars pulling in and pulling out…

if a car chargers has had a lot of down time there is no question they can "buffer" enough electricity to dump electrons at a high rate - like a water tower - but what if the tower is empty?

Lorenfb

Hopefully, consumers considering a BEV won't find this post and conclude;
"I still love my hybrid and a 5 minute gas refill for a 400-500 mile drive without
having to take another lunch break at the Harris Ranch on I5 and wait for an
available SC".