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Discussion Starter #1
So this article suggests that the Taycan when it arrives will be able to charge at 350kW from 800V chargers, and 150kW from 400V chargers.

The topic of how an 800V car will charge from a 400V charger has been discussed before, with the obvious options being:
  1. it won't
  2. it will do so only at a relatively low rate, effectively by reusing the inverter in the onboard AC charger which would allow 22kWish
  3. it will have an onboard DC-DC converter that will be able step up from 400V to 800V at ~400A
  4. it will have a reconfigurable 2-part pack that can be switched from a parallel mode to a series mode.
Personally I've always felt that one of 1 or 2 was the most likely, because 3 is ridiculously impractical and 4 creates lots of technical headaches and introduces lots of extra points of failure into the drivetrain.

But, if this article is to be believed, Porsche have not chosen options 1 or 2.

Does anyone have any knowledge of what they have chosen? @arg?

Or is this just teslarati speculating that charging at 150kW is possible? Does anyone know if Porsche have stated this as a fact?
 

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Its pure speculation, even folk I know in the traction battery field haven't got a sniff of what they are doing in the production one. All I know is porker are really struggling to get the thermal characteristics right.

Given the cost and profile if they are doing this I recon DC-DC converter is involved - but its not a long term solution.
 

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I'm still very interested to know how this is going to turn out, but I'm not sure that there's any more info in these articles. The one you linked at the top of the piece is a second-hand report by Teslarati, acknowledged to be based on an original article in Automobile Magazine:

Ridealong: Porsche's Taycan Turbo Absolutely Redefines Speed and Acceleration


That does have a reference to 150kW charging at 400V, but it's not a quote from Porsche - indeed it's in a piece of aggressively negative writing (perhaps to balance the positive tone of the rest of it), near the start of the article. In the section on specifications (where it talks about 250kW 'now' at 800V stations, 350kW 'by 2021 at the latest', 30 hours to charge at home, 11kW inductive charging and sounds like the official Porsche statement), there's no mention of 400V.

The reference to 400V says:

Even those who are lucky enough to discover one of a handful 400V stations, most of which can typically muster only 150kW, will have to remain idle for at least 40 minutes before the power pack is 80 percent full.

which doesn't sound very well informed - what is this 'handful' of 400V stations?

So I think we are still waiting for real information.
 

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The more I look into the rate of roll out of Ionity post the eTron's release, the more I think they'll go for Option 2.

They are at 100 sites across Europe already. By the time a RHD car arrives I suspect they'll be closing in on their goal of 400 sites. This should be enough to allay fears of potential owners.

It's not really any different to where Tesla were at launch. We had no CHAdeMO and one 2 bay SuC site.

What I think has been more a focus is ensuring the 800V stations also work well with 400v cars, wile building partnerships with other manufacturers to get them on board an 800V topology. It is certainly interesting BMW are mentioned in the press release as having a prototype i3 on 800V.

BMW, Porsche Demo Super-Fast Electric Car Charger - ExtremeTech
 

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I expect it would reduced their sales unless they get close to 50kw on 400volts chargers. They clearly have an inverter for the moters, I don't know if there is a way to design an inverts that is also a DC/DC converter.
 

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@ringi I don't really think they are concerned with hitting sales numbers. They will sell every one they want to sell.

If you look at all the fully loaded Model S cars that come up for sale with <20k on the clock at 3 years old, you'll find the target buyer for the Taycan.

Sure they will lose some customers that want to do starship miles on free unlimited supercharging but so what?

If I were Porsche I'd not want them as customers. Instead concentrating on the wealthiest, selling in restricted volume to maintain the brand mystic.

Ultimately this cars sole purpose is to be more desirable than a Tesla. A headline grabbing charge rate will play a big part in this, even if it comes with the caveat of a smaller but growing network of chargers.

The volume market will be served later down the line by VW.
 

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@mgboyes Is there an option 5? (Thinking aloud here a little).

The AWD cars have 2 independent drive-trains. One 400V pack driving the fronts, one 400v pack driving the rears and a monitoring system that keeps the two packs balanced "through the road" using regen / torque distribution. (With the DC-DC for the 12v & 48v systems doing finer adjustment).

Then you only have to worry about a series / parallel mode selection contactor during a charging session.

One of the other issues I've pondered with the Taycan is that of supply chain. A lot of momentum has built up around 400v (I'm sure in part because of historical use of industrial 3 phase components). A pair of parallel drive systems would therefore remove the need for a slew of Porsche specific 800v rated IGBTs/ wiring / motors etc. etc. downstream of the pack, and they can use 400v items which they share with the likes of the ID3 / eTron.

With this in mind I'm now in the market for a pair of used Leafs..... I can make a four wheel drive one and tie up two Ecotricity points to get 100kW charge rate :sneaky::sneaky:
 

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The AWD cars have 2 independent drive-trains. One 400V pack driving the fronts, one 400v pack driving the rears and a monitoring system that keeps the two packs balanced "through the road" using regen / torque distribution. (With the DC-DC for the 12v & 48v systems doing finer adjustment).
This sounds much more feasible than some of the other possibilities, but I don't think it squares with what Porsche have been saying. For example, you have press releases like this boasting of an 800V motor:

Mission E

I agree with your earlier comments in favour of option 2. The general user experience at existing 50kW networks is rubbish anyhow, so Porsche will be wanting to point their drivers at Ionity as "this is where you will want to be doing your long distance charging, if you really want to you can also go slumming it at those 50kW points you will find at places like Lidl, but they are pre-Porsche technology and not much good". The fact that they are even less good due to lack of 400V capability in the car gets swept under the carpet.

Of course they could be even bolder and go for option 1 - "these 50kW units are rubbish and soon to be obsolete, we recommend you stay away from them".
 

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@ringi I don't really think they are concerned with hitting sales numbers. They will sell every one they want to sell.

If you look at all the fully loaded Model S cars that come up for sale with <20k on the clock at 3 years old, you'll find the target buyer for the Taycan.

Sure they will lose some customers that want to do starship miles on free unlimited supercharging but so what?

If I were Porsche I'd not want them as customers. Instead concentrating on the wealthiest, selling in restricted volume to maintain the brand mystic.

Ultimately this cars sole purpose is to be more desirable than a Tesla. A headline grabbing charge rate will play a big part in this, even if it comes with the caveat of a smaller but growing network of chargers.
Without good surport for 400volt chargers, a customer on holiday for example driving round the Lates or Scotland will find it very hard.
 

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Of course they could be even bolder and go for option 1 - "these 50kW units are rubbish and soon to be obsolete, we recommend you stay away from them".
V interesting thoughts (all), thanks.

I don't think complete incompatibility with the existing 400v units is going to fly. It will make too many places completely inaccessible for too long; they won't want to have to wait for Ionity to cover every last scrap and corner of Europe.

I reckon lower charge rate on 400v units could be supported (in marketing terms) easily enough though - blame for 22kW (or whatever) limit laid on old tech.

it will do so only at a relatively low rate, effectively by reusing the inverter in the onboard AC charger which would allow 22kWish
Inverter? Surely the onboard AC charger is (mostly) a rectifier?
 

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For example, you have press releases like this boasting of an 800V motor:.
I just went over it again and noted that they never say that explicitly.
> 600 hp
are packed and ready for action by two permanently excited synchronous motors (PSM).

800 V
is the voltage with which the components of the Taycan’s drive system works.
A scheme such as the 2x 400V loosely coupled packs, would meet the above description if taken literally. Everywhere else in the release they only talk about "800V technology" or "800V components". Never "800V motors".

I guess we will have to wait to find out...
 

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Discussion Starter #15
V interesting thoughts (all), thanks.

I don't think complete incompatibility with the existing 400v units is going to fly. It will make too many places completely inaccessible for too long; they won't want to have to wait for Ionity to cover every last scrap and corner of Europe.

I reckon lower charge rate on 400v units could be supported (in marketing terms) easily enough though - blame for 22kW (or whatever) limit laid on old tech.
But the vast majority of these legacy 400V units also have 22 or 43kW AC, so if the Taycan has 22kW AC charging anyway then owners can just use that connector.

If they're only going to achieve 22kW by choosing option 2 then they might as well just use option 1, I think.
 

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But the vast majority of these legacy 400V units also have 22 or 43kW AC, so if the Taycan has 22kW AC charging anyway then owners can just use that connector.

If they're only going to achieve 22kW by choosing option 2 then they might as well just use option 1, I think.
Taycan owners join the Zoe owners whinging about Instavolt in 5...4....
 

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Discussion Starter #17
@mgboyes Is there an option 5? (Thinking aloud here a little).

The AWD cars have 2 independent drive-trains. One 400V pack driving the fronts, one 400v pack driving the rears and a monitoring system that keeps the two packs balanced "through the road" using regen / torque distribution. (With the DC-DC for the 12v & 48v systems doing finer adjustment).

Then you only have to worry about a series / parallel mode selection contactor during a charging session.

One of the other issues I've pondered with the Taycan is that of supply chain. A lot of momentum has built up around 400v (I'm sure in part because of historical use of industrial 3 phase components). A pair of parallel drive systems would therefore remove the need for a slew of Porsche specific 800v rated IGBTs/ wiring / motors etc. etc. downstream of the pack, and they can use 400v items which they share with the likes of the ID3 / eTron.

With this in mind I'm now in the market for a pair of used Leafs..... I can make a four wheel drive one and tie up two Ecotricity points to get 100kW charge rate :sneaky::sneaky:
That does sound like it could be technically feasible (and I suspect it's pretty close to what pre-production Tesla Semis are running for example).

But it really flies in the face of Porsche's whole positioning of the car. It's supposed to be the vanguard for VAG's flagship 800V technology, and they've even talked about the fact they've had to get involved in designing 800V native consumers like AC compressors, PTC heaters, etc etc, because their existing suppliers didn't have such products on offer.

Launching a car with the drivetrain you describe as an '800V' vehicle is straying into 'self-charging hybrid' territory in terms of PR, and I don't think that's Porsche's thing.
 

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Launching a car with the drivetrain you describe as an '800V' vehicle is straying into 'self-charging hybrid' territory in terms of PR, and I don't think that's Porsche's thing.
I don't know... there is some fuss at the moment about the vagaries of the latest gen GT4 engine in the Cayman. Is it a detuned GT3, or a Turbo S engine with the turbos unbolted... Porsche let journos run with the former, yet in reality it's the latter. Some nerds will get their knickers in a knot over it, but the reality is they will sell every GT4 they make. (Which will sit in a garage and do under 100 miles a year sat in shrink wrap so it's moot anyway.)

I think the same will also hold true for the Taycan. I think Porsche would get away with pretty much anything at this point as long as it performs like a monster on the road/ track . We know 400V per axle is more than enough to give stupendous performance (as so ably demonstrated by the P100DL).

As you can possibly tell this is the first EV on the horizon that is getting me excited as a credible replacement for the i8 I guess that puts me right into Porsche audience for this car, and honestly I don't care if the individual motors run at 400V, 800V or 4000V.

If it charges fast, drives well, is close to ICE level flexible on trips, is well screwed together and doesn't depreciate like a rock, I'm in.

What I'm more interested in is how they go about the RWD variant. To get 800V charging will you need to buy the Taycan 4S or Taycan Turbo?
 

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Discussion Starter #19
Sounds like the answer is onboard DC-DC converter.

Base car does 50kW from 400V points; optional hardware upgrade (not a very expensive one in fairness) to allow up to 150kW.

11kW AC isn’t very high either...
 

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Sounds like the answer is onboard DC-DC converter.

Base car does 50kW from 400V points; optional hardware upgrade (not a very expensive one in fairness) to allow up to 150kW.

11kW AC isn’t very high either...

Oooh. Very interesting. Do you have a link please?
 
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