ajdelange

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It's amazing how much you can learn from a simple diagram like this one:
CharIn.jpg


A charger has a maximum voltage it can deliver and a maximum current. Most have a power limitation which is less than the product of the maximum voltage and current. Such supplies use "limiting" to keep the supply within its power rating. As an operator increases the voltage setting the current will increase as will the power. When the power limit is reached the operator can no longer increase the voltage and thereby the current. BEV chargers are this type of supply.

There are 3 boxes on the graph above. One formed by the boundaries of the graph itself representing a power supply with 1500 V maximum voltage and 1000 A maximum current. The broken line box represents a supply capable of 920V and 500 A. This bounds the CharIn HPC150 to HPC350 class charger's power supplies. The curved lines represent combinations of voltage and current that represent a fixed power level. An HPC350 class charger has to be able to supply at least 350 kW. It must, therefore, be able to supply any combination of voltage and current on the graph within the broken line box with the upper right corner cut off by the 350 kW power curve.

The smaller dashed line box represents the voltage and current limits of a CharIn HPC50 class charger.

A vehicle's battery system is represented by a "load line" which is monotonic if not quite straight as shown on the graph. If the voltage is increased the current increases. The vehicle can control the duty cycle of the PWM in the charger's modules (it communincates this via a PWM signal but this is a separate PWM circuit reserved for communications). As one turns up this "volume control" he moves from left to right along the load line. The car continuously changes this volume control setting to match the charging profile it wants to implement.

There is tremendous flexibility in the system as currently implemented. There is a reason maximum voltage and current are not specified. And that is that fundamentally there are no limits using this approach. The present limit to CCS right now seems to be the connector which is limited to 1000V and 500A.

In designing a new car the manufacturer only has to insure that his vehicle's load line falls within the envelope of the chargers he wants it to be able to use.

Consider the Tesla or Rivian with their 385 volt battery packs. A hypothetical load line for a 385 V battery might look like the one labeled "Tesla" and extended by the dashed line "Rivian Lo". This load line intersects the HPC350 envelope at 500A and 400 V. The maximum power that these vehicles can get from an HPC350 class charger is 200 kW. This is less than the batteries can handle. So Tesla doesn't use an HP350 charger. It uses its own whose envelope's high current boundary is at 625 A and it is able to get 250 kW from such a charger but the current is a whopping 625A.

The Rivian battery can also take more that 200 kW but they want to use the CCS chargers and so split the battery into two halves and connect them in series. This makes the battery a 780 V battery with a load line like the one labeled "Rivian High" on the graph. This load line reaches the 300 kW power curve inside the HPC350 envelope. It is shown terminated on the 300 kW curve because that is the maximum that this battery pack can take but clearly could it take more it could run right up to the 350 kW envelope edge for this class of charger.

Now note that the 780V battery cannot charge from a HPC50 class charger because such a charger's maximum voltage is limited to 500 V. Switched to the Rivian Lo configuration, thouh, it can.

If some OEM decides he wants to build a car that can charge at 500 kW he knows that he will not be able to use any of the existing class of chargers but just as the existing classes have grown to HPC350 there is no reason there could not be an HPC500 class but it would have to have higher voltage capability (and probably need a new connector). There is no reason a manufacturer can't build a charger that exceeds HPC350 . But he will have to configure his battery pack (and connector bank) to be compatible with the existing classes if he wants to use them too.
 
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In designing a new car the manufacturer only has to insure that his vehicle's load line falls within the envelope of the chargers he wants it to be able to use.
If only it were that simple. There are also multiple communications protocols that can be implemented, and the vehicle must be able to "speak" the same dialect as the charger. Vehicles can be equipped to use multiple communication protocols, and this will ensure the widest range of compatibility.
As an example, the ISO 15118-20 spec is an extension of the more common 15118-2, but it is not backwards compatible. A more detailed discussion here:
https://v2g-clarity.com/blog/new-features-and-timeline-for-iso15118-20/#wpt
 

ajdelange

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If only it were that simple.
It is that simple with respect to the topic under discussion. That is current, voltage and power capabilities of the chargers. One could build a new charger today compliant with 15118-2 and 61851-23 (the current standards) within this architecture and do it this simply (except for the connector).

Obviously your eye was caught by the header "Incompatibility Between ISO 15118-2 and ISO 15118-20" in the article in the link you have posted. This is a separate problem independent of the current discussion and thus irrelevant here. But it is interesting nonetheless.

It would be most unusual for standards to progress in such a way as to prevent backward capability. Were -20 to be adopted by vehicle OEMs such that their products were unable to charge at any of the existing chargers out there today clearly the industry would be in big trouble. Therefore this won't happen. For the foreseeable future new vehicles will have to have systems able to communicate using both standards. Note that this will not be as burdensome as you would like it to be as even the article you site mentions that much of the -2 code base will still be usable in implementations of -20. And similarly on the charger side. Charger and vehicle will communicate using the common protocol. This will go on until nearly all the vehicles on the road and nearly all the chargers in the field have both after which new chargers and new vehicles can be manufactured with only the new standard. This is not at all unusual in industry. Consider the ostensibly seamless progression of the H. codecs used in video compression.
 

ajdelange

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I said that because the HPC150 - 350 box can only take you up to 460 kW. Going only to 500 doesn't add much and thus doesn't really seem worth doing but even so would require 1000 volts. So if one were to go to this trouble it seems that he'd want voltage higher than 1000 and probably current greater than 500 too. Hence new connector.
 

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I said that because the HPC150 - 350 box can only take you up to 460 kW. Going only to 500 doesn't add much and thus doesn't really seem worth doing but even so would require 1000 volts. So if one were to go to this trouble it seems that he'd want voltage higher than 1000 and probably current greater than 500 too. Hence new connector.
Oh ok, thanks!
 

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I reached out to Rivian and got an Email back on Sept 23rd 2020 regarding buying Rivian Gear, when we might see a Configurator and financing.

Short version is the configurator was promised by the end of 2020 along with delivery date windows and financing options from Rivian financing partners.

Regarding a gear store she stated "just around the corner"

Full notes below but it looks like Christmas could be fun.

Side Note: I am very impressed with the tone and the way they are messaging.

Hi Jeremy!

Thanks for your support and for being part of the Rivian community! The Long Way Up is an exciting show and, like you, gets me even more excited as we get closer to delivery and having people behind the wheel. While we are still working through final details, I would like to offer some insight on your questions.

1. Financing Options- Rivian will have flexible financing options available for customers. You will be able to finance a Rivian at the point of purchase through Rivian’s banking relationships.

2. Configurator- the configurator will be launched by the end of this year and will allow you to select your favorite color, trim, battery pack and more for your R1T! It will also give you more detail on pricing for the package you choose as well as your delivery window. It will also allow you to choose financing options at that time.

3. Rivian Store- we would love for you to be walking around in Rivian swag! Our Rivian store is also something currently being finalized and will be launching just around the corner. I am looking forward to a hat myself!

As always, if you have further questions we can help with please let us know!

Your fellow adventuror,
Kristina
I was at the Atlanta event last September (2019) and they also said it was going to be a, I quote exactly "Very Rivian Christmas" in regards tot he store being up and running. I hope it happens soon!!
 

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Sure it wasn't 920?
I did check some ABB chargers near me and they indicate 920V and 400A. But I found online they have 500A capable chargers in Europe that they (ABB) have tested for Porsche, so the technology for 500A does exit.

I also found some info from BTC that claims 950V and 500A, but that 500A is only provided up to 500V, then it tapers down to something like 430A at 950V.

The bottom line for GM is that they have stated their 400V systems will support 200KW charging and the 800V systems will support 350KW. That means they are set up to handle 500A internal to the vehicle. I agree that there will be lower actual charge rates based on the specific charger hardware capability.
 

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Now note that the 780V battery cannot charge from a HPC50 class charger because such a charger's maximum voltage is limited to 500 V. Switched to the Rivian Lo configuration, thouh, it can.
I read an article from Porsche where they indicate using an onboard DC to DC converter to allow charging the 800V system from a 400V charging station, but it is limited to either 50KW or 150KW (optional upgrade). The Taycan supports 270KW at a 800V capable charger. Most of the older chargers are limited to 500V and 50-60 KW anyway, so those are the cases where a DC to DC converter makes sense.
 

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A DC/DC charger is sort of the inverse of the Rivian scheme. Rivian moves the 400 V intercept of its battery load line to 800 V by splitting and series connection. Porsche move the 800 V load line of its battery to 400 V by using a DC/DC converter. I'd think long and hard before I paid for an extra DC/DC converter to let me use 400 V stations. True there are lots of 400 V 50 kW chargers out there but the new EA stations seem to be populated with a couple of HPC350's and a half dozzen HPC150's both of which are capable of 800V.
 

ajdelange

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I did check some ABB chargers near me and they indicate 920V and 400A.
Then techincally it is a FC50 class (Note I called it HPC50 on the graph but it is actually FC50) which must provide at least 50 kW between 200 and 400 V and 5 - 125A but may provide more. Seems odd.

But I found online they have 500A capable chargers in Europe that they (ABB) have tested for Porsche, so the technology for 500A does exit.
Those are HPC350. And yes, according to their slick you can order that from ITT here in the US.

I also found some info from BTC that claims 950V and 500A, but that 500A is only provided up to 500V, then it tapers down to something like 430A at 950V.
That makes it an HPC250 class. See the graph in the earlier post. The 950V capability exceeds the HPC250 requirement but as noted that's allowed. If it is limited to 250 kW the taper would follow the 250 kW curve in the picture. Current at 950 V would be 263A.

The bottom line for GM is that they have stated their 400V systems will support 200KW charging and the 800V systems will support 350KW.
No surprises there if you understand the graph. The 400 volt systems have load lines very like that labeled "Tesla" and the 800V systems have load lines very much like the one labeled "Rivian Hi" but extended to meet the 350 kW contour.

That means they are set up to handle 500A internal to the vehicle.
That means the low voltage vehicle will be dealing with 200000/400 = 500A and that the high voltage ones must safely accept 350000/800 = 437.5 A.

I agree that there will be lower actual charge rates based on the specific charger hardware capability.
So GM has done what it is clear they need to do. Fit their load lines into the envelope of the chargers they want to use. They have decided to go with the HPC350. I'll bet it didn't take a roomful of PHD's to figure that out because I'll bet I'm not the first one to come up with a chart like the one in #76. Note that either the high or low voltage ones will be able to use HPC250 class and HPC150 class but that the high voltage ones will not be able to use FC50 (unless they install a DC/DC converter).
 
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Then techincally it is a FC50 class (Note I called it HPC50 on the graph but it is actually FC50) which must provide at least 50 kW between 200 and 400 V and 5 - 125A but may provide more. Seems odd.

Those are HPC350. And yes, according to their slick you can order that from ITT here in the US.

That makes it an HPC250 class. See the graph in the earlier post. The 950V capability exceeds the HPC250 requirement but as noted that's allowed. If it is limited to 250 kW the taper would follow the 250 kW curve in the picture. Current at 950 V would be 263A.

No surprises there if you understand the graph. The 400 volt systems have load lines very like that labeled "Tesla" and the 800V systems have load lines very much like the one labeled "Rivian Hi" but extended to meet the 350 kW contour.

That means the low voltage vehicle will be dealing with 200000/400 = 500A and that the high voltage ones must safely accept 350000/800 = 437.5 A.



So GM has done what it is clear they need to do. Fit their load lines into the envelope of the chargers they want to use. They have decided to go with the HPC350. I'll bet it didn't take a roomful of PHD's to figure that out because I'll bet I'm not the first one to come up with a chart like the one in #76. Note that either the high or low voltage ones will be able to use HPC250 class and HPC150 class but that the high voltage ones will not be able to use FC50 (unless they install a DC/DC converter).
I expect the GM 800V system to be 720V nominal, which would require close to 500A. My Bolt is 360V nominal, 400V fully charged. But, GM might be changing that for the new Ultium batteries. Someone else pointed out the Taycan is ~720V nominal.
 

ajdelange

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Draw any load line you like. The intersection with the curve for the allowed power gives the current,
Note that the load line will vary with SoC.
 

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I did check some ABB chargers near me and they indicate 920V and 400A.
Then techincally it is a FC50 class (Note I called it HPC50 on the graph but it is actually FC50) which must provide at least 50 kW between 200 and 400 V and 5 - 125A but may provide more. Seems odd.
HPC350 only requires 380A @ 920V, so it meets that spec.
The label may not indicate the 500V portion of the Spec, and it is possible that it is capable of 500A @ 500V and therefore is indeed a HPC350. I don't know if the label is required to list the Amps and Volts at its maximum power output, or the max of each independently. If the former, then it is likely an HPC350 unit

Their current offerings show:
1603212878066.png


1603213013352.png


Possible the installed unit is older with slightly different specs. The CCS power classes were finalized on 6/27/2018, and the ABB unit could very well have been manufactured prior to that based on earlier draft versions of the specs.

I also found some info from BTC that claims 950V and 500A, but that 500A is only provided up to 500V, then it tapers down to something like 430A at 950V.
That makes it an HPC250 class. See the graph in the earlier post. The 950V capability exceeds the HPC250 requirement but as noted that's allowed. If it is limited to 250 kW the taper would follow the 250 kW curve in the picture. Current at 950 V would be 263A.
No, the HPC350 spec has a specific requirement to list the amperage available at 500V. This shows the charging power available on "low power" or "400V" systems (this designation covers packs with a nominal voltage of ~300 to ~450). The first draft of the CCS power specs had a 450V requirement that was later raised to 500V in the final.
• A HPC350 charging station shall support a max. current of 500 A at 500 V at least.
• A HPC350 charging station shall support a max. current of 380 A at 920 V at least.
The 500A @ 500V does not preclude that amperage being available at higher voltages, it simply shows that the unit meets the HPC minimum requirements @ 500V.

The BTC 350 kW units are two 200 kW power cabinets connected in parallel

1603216712461.png


It is worth noting that the "dispensers" have a different rating that may result in getting less that 350 kW (350A @ 950V) and don't meet the HPC350 requirements. A marketing game that allows them to claim the "charger" (cabinet) is 350 kW, but not have that actually available for charging?

That means the low voltage vehicle will be dealing with 200000/400 = 500A and that the high voltage ones must safely accept 350000/8000 = 437.5 A.
That actually depends on the actual battery pack configuration. While most vehicle use a 96s cell configuration giving a nominal voltage of 350V (96 x 3.65V) and max voltage of "400V" (96 x 4.2V = 403V), other configurations are sometimes used. The Porsche Taycan has a 198s configuration giving their "800V" pack a nominal rating of 723V and max voltage of 832.
108s gives a nominal/max of about 400/450 and that is where I think Rivian will be if they stick with low voltage packs. 216s seems to be the optimal design for "800V" packs to stay below the 920V ceiling for CCS compliant chargers (788V nominal, 907V max), and is likely what lucid is using and where Rivian will be if they comeout of the gate with "800V".

Note that either the high or low voltage ones will be able to use HPC250 class and HPC150 class but that the high voltage ones will not be able to use FC50 (unless they install a DC/DC converter).
I think it unlikely that any manufacturer will design a vehicle that cannot use the more common (and less expensive) "low voltage" DCFC units.
 

ajdelange

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HPC350 only requires 380A @ 920V, so it meets that spec.
Afraid you are interpreting the spec incorrectly. In CharIn's own words

HPC350.png


Does a station rated 400A accommodate the dashed blue line to the right of the 400A line on the chart? No. It does not. Clearly then a charger whose labeling says 400A, 920 V does not "acheive HPC350 Class"

As my chart shows the only difference between the HPC250 and HPC150 envelopes and this one are the hyperbolae that chop off the upper right hand corner.


The label may not indicate the 500V portion of the Spec, and it is possible that it is capable of 500A @ 500V and therefore is indeed a HPC350.
An electrical engineer would find that notion absurd. Perhaps it isn't to a layman. No manufacturer labels his products at 25% less than what they are capable of (perhaps a couple percent to make absolutely sure they meet spec). A power supply with maximum voltage rating of 920 V and maximum current rating is capable of delivering 350 kW but only between 920 V x 380.4 A and 875 V x 400 A. A HPC350 can do that out to 500A x 700V.


I don't know if the label is required to list the Amps and Volts at its maximum power output
Again, some knowledge of electrical fundamentals would help you to understand this. It can't do that because there are an infinite number of combinations of voltage and current that correspond to the maximum power. Any point on the hyperbolic curve that chops off the corner represents such a combination.


..or the max of each independently. If the former, then it is likely an HPC350 unit
If the former isn't the case it must be the latter and it follows that the your conclusion does not. A power supply is specified according to its maximum voltage rating, its maximum current rating and, if it is a limiting supply, its maxiumum power or a derating curve is given.


Their current offerings show:
1603212878066.png
I don't know where you are going with this but neither of these are HPC class chargers because neither can satisfy the portions of the HPC envelope above 350V in the one case or 500V in the other.



Possible the installed unit is older with slightly different specs. The CCS power classes were finalized on 6/27/2018, and the ABB unit could very well have been manufactured prior to that based on earlier draft versions of the specs.
Nobody says, AFAIK, that any particular charger out there has to fall into one of the CharIn classes. The reasons industry establishes standards is to make it easier for participants in that industry to achieve compatibility. As standards firm up participants become more confident in them and tend to build gear that meets them.


No, the HPC350 spec has a specific requirement to list the amperage available at 500V.
Afraid that's wrong too. The beauty of the CharIn system is that 99% of the story is conveyed by the first picture in this post. That picture makes it pretty clear that the requirement at 500 V for an HPC350 class charger is that it produce at least 500A. Period. Now there may be in the formal spec a table that lists the points on the plot but the plot provides the same information with perhaps less resolution.


This shows the charging power available on "low power" or "400V" systems (this designation covers packs with a nominal voltage of ~300 to ~450).
And that's wrong too. The power available to a "low voltage" system is the intersection of the system load line with the hyperbola that defines the chargers power limitation as discussed and illustrated in #36.


The first draft of the CCS power specs had a 450V requirement that was later raised to 500V in the final.

A HPC350 charging station shall support a max. current of 500 A at 500 V at least.
Clearly they took that out as it says nothing that isn't clear from the basic spec. An HPC350 system must supply 500A at any voltage up to 700.


• A HPC350 charging station shall support a max. current of 380 A at 920 V at least.
They doubtless took that out for the same reason. The graph specifies that.


The 500A @ 500V does not preclude that amperage being available at higher voltages, it simply shows that the unit meets the HPC minimum requirements @ 500V.
The only requirement for HPC350 class membership is that the supply be able to fill the blue box in the first picture here. It can go from 0 volts at 0 A to a megavolt at a megaamp and meet HPC350.


The BTC 350 kW units are two 200 kW power cabinets connected in parallel
As I've pointed out several times before the chargers are modular. You install as many modules as you need to get the power you want. Relevance?



That means the low voltage vehicle will be dealing with 200000/400 = 500A and that the high voltage ones must safely accept 350000/800 = 437.5 A.
That actually depends on the actual battery pack configuration.
Of course it does. What do you think determines the slope and intercept of the load line?


to stay below the 920V ceiling for CCS compliant chargers (788V nominal, 907V max),

So GM has done what it is clear they need to do. Fit their load lines into the envelope of the chargers they want to use.

I think it unlikely that any manufacturer will design a vehicle that cannot use the more common (and less expensive) "low voltage" DCFC units.
If he's got a high voltage system then he is going to have to fit a DC/DC converter. It's been suggested that Porsche is doing that. That's got to add to the cost of an already expensive car.
 
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