Europe: Future Charging for Model S 1-phase or 3-phase? (Part 2)

[Johan]

It will need to be a minimum of 11kW, preferably 22kW and best would be 43kW.

But wouldn't the draw on each of the legs be limited by the car's internal chargers? I thought the standard charger was able to handle 10kW, the "twin charger option" 2x10kW and the probable solution to three phase charging would be the addition of one more 10kW charger making it a total of 30kW (10 kW for each leg/phase)?

If we look at a supercharger it's basically the same as the on-board charger, only much larger and placed outside of the car. It's function is to take AC power (from the grid) and convert to DC and feed to the battery, just like the on-board chargers. The current version of the supercharger is 90kW. It's made up of 9 of the 10kW chargers (the same ones that are in the cars). I would presume the setup is 3x10+3x10+3x10 where each set of 3 is hooked up the each of the 3 legs of the 3-phase connection? That's why they are talking about the next generation of superchargers to be 120 kW (4x10+4x10+4x10)?

 

[widodh]

So long time no post in this thread. Here in Europe we are jealously seeing US deliveries speeding up. Meanwhile, no news here on pricing, deliveries or on the all-important details of the 3-phase support. I've been thinking a bit about the actual connector-charge port. There are some options here that I think (hope) we can rule out: 1) A separate, second, charge port somewhere else on the car (other side?) 2) Same connector to the car but able to connect to a 3-phase plug however only utilizing one leg (phase) - that would not be 3-phase support so hopefully we can rule that one out as well.

I hope they understood the whole 3-phase issue right now. Just a physical adapter won't do the trick.

Now, what interests me with regards to the design of the connector is how "two-dimensional" it is. By this I mean that it's just a 90 degree cross-section and the contact surfaces are completely round and flat. In no way does it take advantage of depth = the third dimension = z axis. If you would just cut the connector (and of course the "female" connector on the other end accordingly) at say a 45 degree angle you would have quite some more cross sectional area. If the contact surfaces had an added depth, maybe in the form of flat pins (like the ones on a regular 110V US plug) you could have a lot more contact surface without increasing the cross sectional area. Also, you could let the connectors run in close proximity (just like the wires do in the cable), and instead of separating them so much in the x and y plane, you could separate them in the z plane - i.e. one could be "shallow" and one could be "deep" in the charge port. This would of course add some depth to the whole device, but I would think that would be less of a problem than increasing the cross sectional area of the "hole" in the car and also the cross sectional area of the plug it self?

Am I doing some kind of fundamental error with these assumptions?

Couldn't it be that the regulations in the US are a bit looser regarding connectors then they are in the EU? When you compare a NEMA 14-50 to a CEE 32A connector (Red or Blue) you'll notice that they draw much more current over a smaller connector in the US.

To me the NEMA 14-50 connector seems like a hazardous connector. What I'm trying to say, are we even sure Tesla can get the connector certified in the EU? Who knows if that might be the problem?

I still think a lot of options are open here. We haven't heard anything concrete from Tesla on this yet. I'm thinking about sending them an e-mail with a request for some more details. This is very important to European reservation holders.

But wouldn't the draw on each of the legs be limited by the car's internal chargers? I thought the standard charger was able to handle 10kW, the "twin charger option" 2x10kW and the probable solution to three phase charging would be the addition of one more 10kW charger making it a total of 30kW (10 kW for each leg/phase)?

If we look at a supercharger it's basically the same as the on-board charger, only much larger and placed outside of the car. It's function is to take AC power (from the grid) and convert to DC and feed to the battery, just like the on-board chargers. The current version of the supercharger is 90kW. It's made up of 9 of the 10kW chargers (the same ones that are in the cars). I would presume the setup is 3x10+3x10+3x10 where each set of 3 is hooked up the each of the 3 legs of the 3-phase connection? That's why they are talking about the next generation of superchargers to be 120 kW (4x10+4x10+4x10)?

From what I've heard so far the EU Model S will indeed get a third 10kW charger so it COULD charge with 30kW in total.

 

[jkirkebo]

Now, to be able to still use the plug for supercharging DC at 90 kW (120kW in the future?) I assume we must keep the dimension of the two big connectors. To have true 3-phase support we need to add two more large connectors (for leg 2 and leg 3 of the system).

Well, you only need two more connectors if the chargers cannot handle more than 250V or so. If they are made to handle 400V then three connectors are enough since Neutral is not needed (all connections are phase-to-phase).

If you put in two more connectors, you do not need to keep the dimension of the two current ones as the SuperCharger hardware could parallell two of the connectors together. So you have 4 medium ones instead of two small and two large ones.

The 400V solution would IMHO be the best one as just one additional small connector (sized for ~43A if max charging power is 30kW, 63A for 44kW) is needed.

 

[Johan]

Well, you only need two more connectors if the chargers cannot handle more than 250V or so. If they are made to handle 400V then three connectors are enough since Neutral is not needed (all connections are phase-to-phase).

Is the 3-phase systems designed like that in all of Europe?

If you put in two more connectors, you do not need to keep the dimension of the two current ones as the SuperCharger hardware could parallell two of the connectors together. So you have 4 medium ones instead of two small and two large ones.

Now that it pure genius. Hadn't thought of that simple but elegant solution. That would be a compelling case for 4 medium sized pins (+ the signaling pins).

The 400V solution would IMHO be the best one as just one additional small connector (sized for ~43A if max charging power is 30kW, 63A for 44kW) is needed.

Agreed. I'm building a garage right now, and planning on wiring 3 phase, 400 V, 40A from the main house to the new garage, and putting a separate breaker box, transformer and what-not in the garage. That should cover it well I would think. I think it's unlikely the Model S will support 44kW (the Renault Zoe is rated at 43kW but assuming you mean the equivalent?) because of the modular design with the 10kW chargers. 30kW would be good enough for AC charging.

 

[jkirkebo]

Is the 3-phase systems designed like that in all of Europe?

Everywhere but Albania and parts of Norway. In those places the 3-phase system has only 230V between phases and no Neutral. Thus it can only be used delta-connected, not star/wye. A 4 connector solution thus won't work in those places while a 3 connector solution should.

I think it's unlikely the Model S will support 44kW (the Renault Zoe is rated at 43kW but assuming you mean the equivalent?) because of the modular design with the 10kW chargers. 30kW would be good enough for AC charging.

230V*3*63A=43.5kW to be more exact. So yes, it's the same. 43kW if rounded down correctly and 11/22/44kW if you prefer clean multiples

And I'd really prefer 44kW to 30kW as my guess is that we will get a boatload of 44kW AC charging points here in Norway and very few (if any) SuperChargers. We already have a couple of 44kW chargers operational in the vincinity of me.

Of course, if we actually do get a CHAdeMO adapter I have little use for 44kW AC charging. 22kW is good enough then.

 

[Johan]

Everywhere but Albania and parts of Norway. In those places the 3-phase system has only 230V between phases and no Neutral. Thus it can only be used delta-connected, not star/wye. A 4 connector solution thus won't work in those places while a 3 connector solution should.

Thankfully where I live in Norway (Drammen) I have 63A/400V as my mains connection. Not planning on moving to Albania either :tongue:

230V*3*63A=43.5kW to be more exact. So yes, it's the same. 43kW if rounded down correctly and 11/22/44kW if you prefer clean multiples

And I'd really prefer 44kW to 30kW as my guess is that we will get a boatload of 44kW AC charging points here in Norway and very few (if any) SuperChargers. We already have a couple of 44kW chargers operational in the vincinity of me.

Of course, if we actually do get a CHAdeMO adapter I have little use for 44kW AC charging. 22kW is good enough then

How would Tesla go about enabling 44kW with their current modular design? It wouldn't be possible for one 10kW charger to take input from multiple legs simultaneously, would it? The optimal thing would be to have 3x15kW chargers instead. Maybe Tesla would make those for the EU market?

 

[dpeilow]

230V*3*63A=43.5kW

This should be 230V*sqrt 3*63A=25kW

 

[LuckyLuke]

Are you sure?
I remember 3 x 230V x 16A is about 11kW. So 3 x 230V x 64A would be ~ 44kW

 

[dpeilow]

No you are wrong: 3 phase 400 V @ 16A is 11 kW

 

[Johan]

He probably meant 400V/63A in 3-phase which is 43.5kW. Just a slip as we had just discussed the somewhat amusing fact that parts of Norway proudly shares having 230V 3-phase with Europe's poorest country: Albania.

 

[Johan]

I haven’t been able to find detailed specs of the connector. Looking at the picture below of the connector and doing a crude measurment of my own hand (I have ”normal size” hands) I come up with the following dimensions:

So, if the diameter of the large pin i 20 mm the surface area will be 314 mm2. This pin apparently is dimensioned to carry up to 120 kW of DC current, at a Voltage in the 300 range (as shown in the supercharging videos on this site) that would mean an Amperage of somewhere between 300-400 Amps.

Now, taking the above idea of instead having 4 smaller connectors where you use 3 of them for 3-phase charing and you pair them two-and-two in parallell for supercharging then in the 3-phase mode each one would have to be able to handle probably a maximum of 63A at 400V maximum, while in DC (supercharge mode) each would have to be able to handle a maximum of 200A. So the limiting factor here would of course be DC charging. How large would the cross sectional area of each connector have to be to handle up to 200A? I’d say half of what it is now, or around 160 mm2. That would give us a required diameter of about 14 mm, instead of 20. Of course some spacing is required. Is this possible without changing the outer dimensions of the the connector/charge port? I believe so, here is a crude sketch of what it could look like:

Note that the recessed/hollow area in the center of the connector is now split into three separate "hollows". Could still function well as a "guide" to make sure the plug is centered and in the correct position in the charge port, however I don't fully understand if this hole is an important part of the locking feature of the charge plug?

Also see the following overlays of areas where red=connector/pin, yellow=flat area/insulation and green=hollow part

 

[widodh]

That seems very do-able Johan! One thing that should not be forgotten (which you don't) is that neutral will always be needed since the car should be able to do single-phase when plugged into a 13A outlet for example.

Judging on your pictures it seems the holes should be about the size of those in the current Type 2/Mennekes connector.

 

[donauker]

I haven’t been able to find detailed specs of the connector. Looking at the picture below of the connector and doing a crude measurment of my own hand (I have ”normal size” hands) I come up with the following dimensions

View attachment 10890

Total width is 38 mm and large pin diameter approximately 9.5 mm

 

[Johan]

Thanks for the reality check! The person in the photo must have really small hands. My suggested scaling would be the same though, regardless of absolute dimensions.

Also, since you have the car, do uou believe that the central hole structure is integral for locking in of the connector?

 

[donauker]

Thanks for the reality check! The person in the photo must have really small hands. My suggested scaling would be the same though, regardless of absolute dimensions.

Also, since you have the car, do uou believe that the central hole structure is integral for locking in of the connector?

No, I believe the central structure is merely a guide. The locking is a crosswise slot on the outside of the connector.

 

[doug]

90iuhbv

So, if the diameter of the large pin i 20 mm the surface area will be 314 mm2. This pin apparently is dimensioned to carry up to 120 kW of DC current, at a Voltage in the 300 range (as shown in the supercharging videos on this site) that would mean an Amperage of somewhere between 300-400 Amps.

Now, taking the above idea of instead having 4 smaller connectors where you use 3 of them for 3-phase charing and you pair them two-and-two in parallell for supercharging then in the 3-phase mode each one would have to be able to handle probably a maximum of 63A at 400V maximum, while in DC (supercharge mode) each would have to be able to handle a maximum of 200A. So the limiting factor here would of course be DC charging. How large would the cross sectional area of each connector have to be to handle up to 200A? I’d say half of what it is now, or around 160 mm2. That would give us a required diameter of about 14 mm, instead of 20...

I made a similar suggestion about a year ago hoping Tesla would have made a single world connector. Just want to point out that for these contacts, the relevant figure of merit is the sidewall surface area which varies linearly with the diameter (instead of some cross sectional area, as you suggest, which would vary with the square of the radius).

To a good first order approximation, the contact area is the side of a cylinder given by pi*d*l, where d is the diameter and l is the insertion length. Remember also that the contacts include an additional center pin that further increases the surface area.

 

[FlasherZ]

There may not be enough isolation if the pins are placed that close together - arcing could occur.

 

[Johan]

I made a similar suggestion about a year ago hoping Tesla would have made a single world connector.

I second this! But too late know I guess...

Just want to point out that for these contacts, the relevant figure of merit is the sidewall surface area which varies linearly with the diameter (instead of some cross sectional area, as you suggest, which would vary with the square of the radius).

To a good first order approximation, the contact area is the side of a cylinder given by pi*d*l, where d is the diameter and l is the insertion length. Remember also that the contacts include an additional center pin that further increases the surface area.

Thank you for this, and the picture you attached which shows the connector from a better angle. I have never had the chance to see the connector in real life and I misenterpreted the image I had - I thought the pins/connection surfaces were actually large, round and flat surfaces where as it now turns out they are in fact pins surrounded by spacing. What you point out about the surface are is of course correct and very relevant, and as I tried to point out in one of my posts a little earlier, it might be possible to separate the pins in the 3rd (Z) dimension if there is not enough room to do it in the X-Y dimension on the connector.

There may not be enough isolation if the pins are placed that close together - arcing could occur.

True, especially at higher voltages (probably maximum 400V). Hence maybe as suggested above you could separate the pins in X, Y and Z dimension.

 

[jkirkebo]

He probably meant 400V/63A in 3-phase which is 43.5kW. Just a slip as we had just discussed the somewhat amusing fact that parts of Norway proudly shares having 230V 3-phase with Europe's poorest country: Albania.

For a 400V system you can calculate two ways. Either you use the phase-to-neutral voltage and multiply by 3, or you use the phase-to-phase voltage and multiply by SQRT(3).

For a 230V system you must use the phase-to-phase voltage and multiply by SQRT(3) since there is no neutral and all loads must be phase-to-phase connected.

- - - Updated - - -

How would Tesla go about enabling 44kW with their current modular design? It wouldn't be possible for one 10kW charger to take input from multiple legs simultaneously, would it? The optimal thing would be to have 3x15kW chargers instead. Maybe Tesla would make those for the EU market?

I think the better way would be to make 22kW 3-phase chargers for the EU market. One standard and you pay extra for the second one to enable 44kW.

- - - Updated - - -

That seems very do-able Johan! One thing that should not be forgotten (which you don't) is that neutral will always be needed since the car should be able to do single-phase when plugged into a 13A outlet for example.

Nope. If Tesla puts in chargers that handle 400V input they should also handle 230V input. So where a 3-phase supply would use L1,L2 and L3 a single phase supply would be conneted to just L1 & L2.

Neutral is only needed if the chargers do not handle 400V input.

 

[widodh]

Nope. If Tesla puts in chargers that handle 400V input they should also handle 230V input. So where a 3-phase supply would use L1,L2 and L3 a single phase supply would be conneted to just L1 & L2.

Neutral is only needed if the chargers do not handle 400V input.

That might be the case in Norway, but in the Netherlands we also have chargers which only have L1 connected.

So you have 16A between L1 and N, 3.6kW.

In Norway L2 is connected on "N" I guess?

Regarding the 44kW charging, see my post in the CHAdeMO thread: TEPCO/CHAdeMO Level III charging station/connector - Page 32

Since adapters are not allowed on the car side they Model S should have a native Type 2 inlet to charge on 44kW since those charging stations have a fixed cable.

Only 22kW EVSE systems have a Type 2 socket where you plug in your own cable.

I also informed at a source at Tesla and he told me: "We are making good progress. I can't give any details right now"