SAE vs CHAdeMO

[Larry Chanin]

That all depends on what strategy Tesla wishes to pursue when it comes to third party chargers. It simply doesn't make sense for Tesla to want to own every single DC charging station. So either they license the supercharger protocol for other people to adopt, or they provide adaptors for one or both of the other standards. What direction Tesla wants to go for North America remains uncertain, and will have a huge influence.

Hi Greg,

I think that if other manufacturers contract with Tesla to produce powertrains, or license the technology that can accommodate Supercharging, it is a certainty that Tesla will also offer access to the Supercharging network for a price or a partership that expands the network. I also think it is virtually certain that Tesla will produce adapters for CHAdeMO and SAE combo. However, since Superchargers are supposed to offer an unpresidented sophistication in communicatng with the Model S battery system, I doubt they would ever permit another unlicensed battery system to connect to a Tesla Supercharger via an adapter.

Larry

 

[TonyWilliams]

However, since Superchargers are supposed to offer an unpresidented sophistication in communicatng with the Model S battery system, I doubt they would ever permit another unlicensed battery system to connect to a Tesla Supercharger via an adapter.

Larry

According to Tesla, the Supercharger is "100%" Frankenplug compliant. I doubt that there is much extra communication going on.

There's also no reason why the Tesla Supercharger couldn't be licensed to a lowly Chevy Spark (with optional Frankenplug port and a Supercharger adaptor). If GM pays Tesla the asking price, and offers whatever security encryption they may have, then plug in and go.

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Hi Tony,

I think you summarized that nicely. :biggrin:

The thing is this isn't a sprint. This is going to be an indurance race. You know the outcome won't be resolved in just a year. In fact, when this DC Charging race is finished it wouldn't surprise me if neither of these two competitors are still in the running and some dark horse that is building compelling EVs and a proprietary charging network wins. :wink:

Larry

This war will go on for a LOOOoooooong time. The Germans are already planning the next things, inductive and higher power DC (Mode 4): The IEC working group for TC 23/SC 23H/PT 62196-3 (max. 1000Vdc / 400A plugs) has been approved for new work. Specifications on DC charging have already begun on the national level.

Tesla will be on their own for a long time, or the governments around the world will force them to adopt the standards for every country in the world. The latter is looking like a distinct possibility. I just know that every time somebody says, "let's have one standard", it usually means, "let's add yet another standard".

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Hi Tony,

I think you summarized that nicely. :biggrin:

The thing is this isn't a sprint. This is going to be an indurance race. You know the outcome won't be resolved in just a year. In fact, when this DC Charging race is finished it wouldn't surprise me if neither of these two competitors are still in the running and some dark horse that is building compelling EVs and a proprietary charging network wins. :wink:

Larry

Governments around the world can shut that down in a nanosecond. A future bill in some government law making office:

"No electric vehicle shall be sold in (government's jurisdiction) without brand Z national electric plug standard. Chargers in the jurisdiction that do not meet the new standard must be dismantled and destroyed."

 

[Larry Chanin]

This war will go on for a LOOOoooooong time.

Yes, I believe that is what I said. So taking a snapshot of the DC fast charging status after a year would have very little meaning in the general scheme of things.

Tesla will be on their own for a long time, or the governments around the world will force them to adopt the standards for every country in the world. The latter is looking like a distinct possibility. [...]

Governments around the world can shut that down in a nanosecond. A future bill in some government law making office:

"No electric vehicle shall be sold in (government's jurisdiction) without brand Z national electric plug standard. Chargers in the jurisdiction that do not meet the new standard must be dismantled and destroyed."

Really? Do you seriously think that the US government will force Tesla to abandon their Supercharger network? Maybe the State of North Carolina, but not the Federal Government. :wink:

Larry

 

[brianman]

Do you seriously think that the US government will force Tesla to abandon their Supercharger network?

In politics, I don't believe anything "can't happen" anymore.

 

[Larry Chanin]

In politics, I don't believe anything "can't happen" anymore.

Hi Brian,

True, but do you ascribe a high probability that governments will shut down the North American Supercharger network in a nanosecond? Or do you think it might actually take all of two nanoseconds? :biggrin:

Larry

 

[rolosrevenge]

I still think that if Tesla allows third parties to install super chargers than game over for everyone else. It will be the defacto standard and private companies will rush to setup super charger ports to attract affluent Tesla owners.

 

[Larry Chanin]

I still think that if Tesla allows third parties to install super chargers than game over for everyone else. It will be the defacto standard and private companies will rush to setup super charger ports to attract affluent Tesla owners.

I agree except first Tesla must overcome the current production rate limitations to attract a critical mass. That critical mass may be automakers that license Tesla technology or charger supply companies and their clients. Then Tesla will have to overcome the battery supply issue that Elon has discussed recently. That's a big deal that might require Tesla to fund battery factories. He's talking about a significantly larger battery supply than the current computer battery industry. So this won't be a slam dunk. However, if Tesla is the first to produce and sell more than 100,000 EVs per year, then I agree, as you say game over.

Larry

 

[scottf200]

A few cars in two states falls into the none planned category. Quick charger installation is not cheap, so only a fool would invest money in something like that. You won't be seeing ANY of these chargers UNLESS the installation is fully paid for by taxpayers.

Except for the Nissan Dealers, you could see the SAE CCS/combo exactly where the chademo chargers are today since most of the work was done to get that location and the necessary kW's to it. This is ideal for the dual "multi-standard" setup.

 

[Larry Chanin]

Except for the Nissan Dealers, you could see the SAE CCS/combo exactly where the chademo chargers are today since most of the work was done to get that location and the necessary kW's to it. This is ideal for the dual "multi-standard" setup.

Hi Scott,

I know that Nissan has gone on record as supporting dual standard DC fast chargers, but do you think that they would actually fund such chargers?

Thanks.

Larry

 

[stopcrazypp]

Exactly, Tesla is the automaker that is most likely to be the first to sell hundreds of thousands of EVs a year. If so, the Supercharging protocol will emerge as the dominant DC fast charging protocol. If the other automakers don't move quickly, and cwerdna suggests they are not, then SAE combo vs. CHAdeMO battle will become irrelevant.

Like TonyWilliams says, the "supercharging protocol" IS SAE Combo (or extremely similar, but I suspect it's SAE Combo with an extra layer transmitted via the built in PLC; SAE chose PLC precisely because it allows extra custom communication and it's a prime way for Tesla to prevent other cars from charging at superchargers even if an adapter was made). What Tesla primarily will be licensing is access to superchargers, not really the protocol.

And all that comes down to is if Tesla wants others cars to use their port, not the protocol. And I find that unlikely given their strategy with J1772 AC. Most people/businesses will not be willing to change their J1772 stations to support a new port. SAE realized this, which is why they designed Combo to be backwards compatible (rather than taking the suggestion of some, which is to design a port similar to Tesla's without extra DC pins). The ideal thing would have been to have DC charging support in the J1772-2010 (DC support existed for the previous AVCON port, but was taken out because the Yazaki connector did not support DC), but they had to get that ready for Leaf and Volt release, so there was not enough time.

Most likely is that even when Tesla allows other cars access to superchargers, it'll be via adapter or an extra SAE DC connector. The most Tesla might be able to get others to do is to add a Tesla connector to other non-Tesla DC stations. But the adapter strategy will probably continue.

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I know that Nissan has gone on record as supporting dual standard DC fast chargers, but do you think that they would actually fund such chargers?

Nissan's doing that only because they know the writing is on the wall for CHAdeMO in EU (I don't believe they have made similar announcements in the US). If they did not support dual standard fast chargers, there would be virtually no chance of CHAdeMO being included in the plans of the EU.

I think they would only fund such chargers if they made one themselves. Their current charger line-up is CHAdeMO-only.

 

[Larry Chanin]

Like TonyWilliams says, the "supercharging protocol" IS SAE Combo (or extremely similar, but I suspect it's SAE Combo with an extra layer transmitted via the built in PLC; SAE chose PLC precisely because it allows extra custom communication and it's a prime way for Tesla to prevent other cars from charging at superchargers even if an adapter was made). What Tesla primarily will be licensing is access to superchargers, not really the protocol.

And all that comes down to is if Tesla wants others cars to use their port, not the protocol. And I find that unlikely given their strategy with J1772 AC. Most people/businesses will not be willing to change their J1772 stations to support a new port. SAE realized this, which is why they designed Combo to be backwards compatible (rather than taking the suggestion of some, which is to design a port similar to Tesla's without extra DC pins). The ideal thing would have been to have DC charging support in the J1772-2010 (DC support existed for the previous AVCON port, but was taken out because the Yazaki connector did not support DC), but they had to get that ready for Leaf and Volt release, so there was not enough time.

Most likely is that even when Tesla allows other cars access to superchargers, it'll be via adapter or an extra SAE DC connector. The most Tesla might be able to get others to do is to add a Tesla connector to other non-Tesla DC stations. But the adapter strategy will probably continue.

Thanks for the response.

Rather than the quote you selected I assume you really meant to respond to the following:

However, since Superchargers are supposed to offer an unpresidented sophistication in communicatng with the Model S battery system, I doubt they would ever permit another unlicensed battery system to connect to a Tesla Supercharger via an adapter.

Let me ask a basic question. Do you see the issue of an adapter that permits Model Ss to connect to CHAdeMO or SAE combo the same as an adapter that permits a car with a CHAdeMO port or SAE combo port to connect to a Supercharger?

My thinking is that Tesla will only permit non-Tesla vehicles to access the Supercharging network if the manufacturer had licensed Tesla technology and for all intents was plugging essentially a Tesla powertrain into the Supercharger.

Tesla makes a big deal of the fact that its Supercharger talks to the Tesla battery system, monitoring key parameters and adjusting the charge rate accordingly. Assuming a Chevy Spark had a physical adapter to connect its SAE combo port to a Tesla Supercharger, are you and Tony saying that the SAE protocol is sufficiently similar that there would be no problems? I find it difficult to believe that without the same sort of battery to Supercharger handshake as Model Ss enjoy, that Tesla would never permit cars that do not have licensed Tesla technology to charge from Tesla Superchargers.

Thanks.

Larry

 

[stopcrazypp]

Let me ask a basic question. Do you see the issue of an adapter that permits Model Ss to connect to CHAdeMO or SAE combo the same as an adapter that permits a car with a CHAdeMO port or SAE combo port to connect to a Supercharger?

No, they are not the same at all. The thing to keep in mind is the adapter can't be used both ways and the two sides (car vs charger) do not have symmetric roles.

My thinking is that Tesla will only permit non-Tesla vehicles to access the Supercharging network if the manufacturer had licensed Tesla technology and for all intents was plugging essentially a Tesla powertrain into the Supercharger.

Tesla may very well have that requirement. However, if it's true that Tesla is using SAE DC, then it's unnecessary for the cars to have a Tesla powertrain (or even Tesla charging equipment) in it. All Tesla has to do is to enable that car to charge on the network (might need to be some software installed in that car) and the car can do so via adapter (even though current will be reduced because of the physical limitations of the pins for the SAE DC connector).

Tesla makes a big deal of the fact that its Supercharger talks to the Tesla battery system, monitoring key parameters and adjusting the charge rate accordingly. Assuming a Chevy Spark had a physical adapter to connect its SAE combo port to a Tesla Supercharger, are you and Tony saying that the SAE protocol is sufficiently similar that there would be no problems? I find it difficult to believe that without the same sort of battery to Supercharger handshake as Model Ss enjoy, that Tesla would never permit cars that do not have licensed Tesla technology to charge from Tesla Superchargers.

The way DC charging works for both SAE DC and CHAdeMO is the car tells the DC charger what battery voltage/current it wants and the DC charger provides it. The DC charger is not the one making the decisions on what voltage/current to use based on identifying the car, because if it was designed that way, the charger would only be able to charge cars it recognizes (and would have to be updated continually to support new cars, which is a horrible design)! Plus, the car's BMS is the one that knows the battery best, so there is no need for another offboard BMS on the Supercharger to make decisions.

Now it's possible for Tesla to design the charger such that the charger makes decisions on charging parameters, but it's more likely for Tesla to follow conventional design. Plus there are lots of other similarities with SAE DC that I point out here that suggests Tesla's using something very similar to or the same as SAE DC:
http://www.teslamotorsclub.com/show...1772-DC-(Combo)-Connector-Adapter-for-Model-S

SAE DC:

-Off-board charger connects directly to vehicle high voltage battery bus
-Charger controlled by vehicle which allows for extremely high power transfer (>100kw) and thus faster recharge times (minutes instead of hours)

http://grouper.ieee.org/groups/earthobservationsSCC/IEEE_SAE_J1772_Update_10_02_08_Gery_Kissel.pdf

You can see open CHAdeMO for an idea of how it works, basically there's a compatibility check and then after that it's the car that continually tells the charger what current to charge the battery at:
https://code.google.com/p/open-chademo/

 

[Larry Chanin]

The way DC charging works for both SAE DC and CHAdeMO is the car tells the DC charger what battery voltage/current it wants and the DC charger provides it. The DC charger is not the one making the decisions on what voltage/current to use based on identifying the car, because if it was designed that way, the charger would only be able to charge cars it recognizes (and would have to be updated continually to support new cars, which is a horrible design)! Plus, the car's BMS is the one that knows the battery best, so there is no need for another offboard BMS on the Supercharger to make decisions.

Now it's possible for Tesla to design the charger such that the charger makes decisions on charging parameters, but it's more likely for Tesla to follow conventional design. Plus there are lots of other similarities with SAE DC that I point out here that suggests Tesla's using something very similar to or the same as SAE DC:

Thanks for the background.

I see on the CHAdeMO materials that the charger receives the battery parameters from the car. Do you happen to have a feel for what those parameters might be? You stated voltage and current, but are there provisions for other parameters on both standards? The reason I ask is that in the Supercharger FAQ they state:

The Supercharging rate may vary due to battery charge level, current use of the Supercharging station and extreme climate conditions.

This suggests that the Tesla battery is sending state of charge information and temperature readings to the Supercharger. Would this information routinely be provided by other manufacturer's batteries as well? Is it possible that the Tesla Supercharger is expecting a minimum amount of information from the Tesla battery system that might not be guaranteed to be available from other manufacturers, and if it were absent could that halt the charging process?

Thanks.

Larry

 

[brianman]

True, but do you ascribe a high probability that governments will shut down the North American Supercharger network in a nanosecond? Or do you think it might actually take all of two nanoseconds? :biggrin:

It probably takes less than 7 nanoseconds, but we'd have at least 4 decades of pointless debate and handwringing before it would happen anyway.

 

[stopcrazypp]

I see on the CHAdeMO materials that the charger receives the battery parameters from the car. Do you happen to have a feel for what those parameters might be?

This link shows that it's "max voltage to stop charging, target voltage, total battery capacity, etc.".
http://chademo.com/05_protocol.html

But the part you are talking about only happens before charging starts. It's a compatibility check. Once charging starts, the car's BMS monitors the battery and continually transmits the charging current it wants. And that's the only thing it transmits. When the battery reaches the point that the user sets, the car sends a zero-current signal to tell the charger to stop.

You stated voltage and current, but are there provisions for other parameters on both standards?

If I'm getting your implication correctly, what you really want to ask if Tesla can add additional parameters such that non-Tesla (or non-licensed) cars can't charge at superchargers since they won't have them. I don't know about CHAdeMO, but SAE DC does allow additional information to be transmitted via PLC for things like V2H or V2G, Remote charging, certified payment/billing, etc. So Tesla can certainly use that to restrict the cars that can use superchargers.
http://electricdrive.org/index.php?ht=a/GetDocumentAction/id/32211

The reason I ask is that in the Supercharger FAQ they state: The Supercharging rate may vary due to battery charge level, current use of the Supercharging station and extreme climate conditions.
This suggests that the Tesla battery is sending state of charge information and temperature readings to the Supercharger.

Actually it doesn't, because this can also be accomplished by the car continually sending only a requested current/voltage and the charger responding with the available current/voltage. That's how the CHAdeMO protocol basically works. No battery information has to be transmitted for charging to happen (CHAdeMO does do that in the start as a compatibility check, but doesn't need that info while charging). The car does all the monitoring of charge level, climate conditions, and other battery conditions.

The charger only acts a DC power supply being controlled by the vehicle. It can lower or raise the available current/voltage based on use of the station, but it must provide no more than the current the car requests.

Would this information routinely be provided by other manufacturer's batteries as well? Is it possible that the Tesla Supercharger is expecting a minimum amount of information from the Tesla battery system that might not be guaranteed to be available from other manufacturers, and if it were absent could that halt the charging process?

Tesla doesn't have to do that. All it has to do is to add a special process to the handshake to verify the car is an authorized part of the network. Then charging can proceed as it does for either SAE DC or CHAdeMO.

As I pointed out previously, SAE DC allows use of its PLC for payment processing to happen. Tesla can simply use that for subscription verification (similar to what existing charging networks are doing with RFID) and treat the supercharger network like one of the many subscription charging networks (Charge Point, Blink, etc).

 

[TonyWilliams]

If I'm getting your implication correctly, what you really want to ask if Tesla can add additional parameters such that non-Tesla (or non-licensed) cars can't charge at superchargers since they won't have them. I don't know about CHAdeMO, but SAE DC does allow additional information to be transmitted via PLC for things like V2H or V2G,

The latest CHAdeMO (I think 1.09 from memory) can do V2H. I doubt that they are sending payment processing, but I like that idea.

I wonder if they is a way to send the GreenPHY PLC over any of the existing CHAdeMO pins, and vice versa... send CAN messages via GreenPHY PLC to Tesla / Frankenplug.

If that could be worked out, the whole adapter thing disappears. You would only need a "pass through" physical adaptor to make any DC charger work.

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BMW was my only hope for a Frankenplug savior in the USA. Well, it looks like I was right. Frankenplug is DEAD ON ARRIVAL if nobody will pick up the torch and run with it. It looks like the BMW i3 might have been a strict CARB-ZEV compliance car after all, which means that they aren't going to spend Frankenbucks on Frankenplugs:

Tesla Motors Inc (NASDAQ:TSLA) board member Steve Jurvetson spoke with FOX Business Network’s (FBN) Melissa Francis about the future of Tesla Motors Inc (NASDAQ:TSLA). Jurvetson said, On whether Tesla investor’s should be worried about the new BMW electric car that is coming out next year:

“Well, both Elon and I burst into laughter with the questions just because Bayerische Motoren Werke AG (FRA:BMW) itself said – and I’ve never heard any product release say this a year before its release – we’re not trying to make the best electric car; we’re building this vehicle because we have to for regulatory reasons. They’re basically they’re saying don’t judge us by this car and whether it’s any good or not a year before it’s released. It’s totally a different kind of product. It doesn’t have very good range; and they’re putting in a gasoline lawnmower engine in there as a backup. It’s kind of an odd duck.”

Tags: BMW, Electric car, FBN, Fox Business, hybrid car, Steve Jurvetson, Tesla

This entry was posted on August 21, 2013 at 4:24 pm and is filed under Business.

http://www.valuewalk.com/2013/08/tesla-motors-board-member-laughs-at-bmw/

 

[arg]

Tesla makes a big deal of the fact that its Supercharger talks to the Tesla battery system, monitoring key parameters and adjusting the charge rate accordingly. Assuming a Chevy Spark had a physical adapter to connect its SAE combo port to a Tesla Supercharger, are you and Tony saying that the SAE protocol is sufficiently similar that there would be no problems? I find it difficult to believe that without the same sort of battery to Supercharger handshake as Model Ss enjoy, that Tesla would never permit cars that do not have licensed Tesla technology to charge from Tesla Superchargers.

Just to further amplify the points already made:

- To connect a Chevy Spark (or whatever) to a Tesla Supercharger, you need to solve the mechanical connection issue, and you need to add whatever authentication (software) Tesla are using to deny supercharger access to unauthorized vehicles. Both these are straightforward to do (assuming Tesla's connivance). Once so connected, the Spark would have no problem charging.

- A Spark charging from a Supercharger would not get Supercharger rates of charge - maybe 40kW or so. Tesla's advantage is partly from simply having a larger battery (in the way that the S85 charges faster than the S60), but their special sauce is in the cooling and monitoring of the battery that lets them take the charging rate right to the edge of what the cells can accept. The Spark will have to take a more conservative approach since it doesn't (so far as we know) have such detailed knowledge and control of the battery. But in either case it's the car making the decisions and the DC (super-)charger just does what it is told.

 

[brianman]

- To connect a Chevy Spark (or whatever) to a Tesla Supercharger, you need to solve the mechanical connection issue, and you need to add whatever authentication (software) Tesla are using to deny supercharger access to unauthorized vehicles. Both these are straightforward to do (assuming Tesla's connivance). Once so connected, the Spark would have no problem charging.

- A Spark charging from a Supercharger would not get Supercharger rates of charge - maybe 40kW or so. ...

Isn't this kind of like saying attaching a straw to a garden hose "will just work"? How do you know this?

 

[Dave EV]

Isn't this kind of like saying attaching a straw to a garden hose "will just work"? How do you know this?

Go read stopcrazypp's post above again - he explains it in detail.

To summarize - the car is in charge of how much power the car gets - the Spark EV simply tells the charger that it needs less current. So as long as you solve the mechanical and software communication, you should have no problem charging.

I personally don't buy the "Tesla has more detailed knowledge of it's pack than others which allows for faster charging" argument - all factory BMS systems I've seen track battery cell voltages at the same level - not doing so would risk over charging or discharging a cell during regular use which would very likely end in catastrophic cell failure. Tesla monitors the voltage of each sheet (hundreds of cells in parallel) - around 3.7V nominal. Others using large-format cells monitor at the same level - they may not have any cells in parallel or only a couple - but they're still monitoring the same appx 3.7V nominal voltage of every cell.

If you compare the Nissan LEAF charge rate to Tesla charge rate as it currently sits (50 kW peak vs 90 kW peak) the Nissan LEAF pack is getting pushed at over a 2C charge rate while the Tesla is only getting pushed at slightly more than a 1C charge rate. Even if Tesla was currently using 120 kW, that's still only a 1.4C charge rate (85 kWh pack) - it's not as fast as the LEAF. You'd have to charge the Tesla at up to 170 kW to reach the same charge rate as the Nissan LEAF.

 

[Larry Chanin]

If I'm getting your implication correctly, what you really want to ask if Tesla can add additional parameters such that non-Tesla (or non-licensed) cars can't charge at superchargers since they won't have them. I don't know about CHAdeMO, but SAE DC does allow additional information to be transmitted via PLC for things like V2H or V2G, Remote charging, certified payment/billing, etc. So Tesla can certainly use that to restrict the cars that can use superchargers.

Just to further amplify the points already made:

- To connect a Chevy Spark (or whatever) to a Tesla Supercharger, you need to solve the mechanical connection issue, and you need to add whatever authentication (software) Tesla are using to deny supercharger access to unauthorized vehicles. Both these are straightforward to do (assuming Tesla's connivance). Once so connected, the Spark would have no problem charging.

- A Spark charging from a Supercharger would not get Supercharger rates of charge - maybe 40kW or so. Tesla's advantage is partly from simply having a larger battery (in the way that the S85 charges faster than the S60), but their special sauce is in the cooling and monitoring of the battery that lets them take the charging rate right to the edge of what the cells can accept. The Spark will have to take a more conservative approach since it doesn't (so far as we know) have such detailed knowledge and control of the battery. But in either case it's the car making the decisions and the DC (super-)charger just does what it is told.

Thanks guys for the very helpful explanations.

Where I was coming from with my series of questions wasn't the issue of whether Tesla would be able to prevent certain vehicles from charging at a Supercharger. It was would Tesla question the safety of permitting a non-Tesla battery from connecting to a Supercharger since, as arg puts it, they lack Tesla's special sauce in cooling and monitoring the battery?

From your excellent explanations it would seem that other non-Tesla battery systems, regardless of their sophistication, would simply ask for charge rates consistent with their reduced needs and as a result would charge must slower.

This being a non-issue it would appear that Tesla has more viable options than I had orignially thought to open up the Supercharger network to other vehicles capable of DC fast charging if the price is right.

Larry

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I personally don't buy the "Tesla has more detailed knowledge of it's pack than others which allows for faster charging" argument - all factory BMS systems I've seen track battery cell voltages at the same level - not doing so would risk over charging or discharging a cell during regular use which would very likely end in catastrophic cell failure. Tesla monitors the voltage of each sheet (hundreds of cells in parallel) - around 3.7V nominal. Others using large-format cells monitor at the same level - they may not have any cells in parallel or only a couple - but they're still monitoring the same appx 3.7V nominal voltage of every cell.

If you compare the Nissan LEAF charge rate to Tesla charge rate as it currently sits (50 kW peak vs 90 kW peak) the Nissan LEAF pack is getting pushed at over a 2C charge rate while the Tesla is only getting pushed at slightly more than a 1C charge rate. Even if Tesla was currently using 120 kW, that's still only a 1.4C charge rate (85 kWh pack) - it's not as fast as the LEAF. You'd have to charge the Tesla at up to 170 kW to reach the same charge rate as the Nissan LEAF.

You make an interesting point, and that's with air cooling for the Leaf versus liquid cooling for the Model S.

However, this may merely be a temporary limitation on the part of Tesla while they test the longevity of their batteries in real word situations. Perhaps they will eventually increase the Supercharger capacity beyond 120kW after they are comfortable with warranty issues.

Larry