Tesla opening up the Supercharger network in Australia to other brand EVs.

[TrevRex]

The biggest mistake Tesla made was not designing NACS with 3phase in mind, it could have then become the de facto world standard. I still believe 3phase could have been useful in North America, sure its basically non existant in residential areas, but it would still have made AC charging easier to implement in commercial environments. Type2 is now a standard in North America as highlighted by J3068 (Type 2) SAE J3068 - Wikipedia

I agree, that CCS2 is still superior to NACS. The big deal about how clunky the connector is the fault of cable and plug manufacturers, the CCS2 handles at Tesla Supercharger locations are very easy to handle, and when using the DC-less form, type 2, its close enough the same as NACS.

Anyway, I see the war as basically over, long term its NACS and CCS2 outside of Japan and China.

My biggest interest now is if Ford will do the same access agreement to the Supercharger network outside of North America.

From an engineering standpoint from Tesla's released NACS documents that hit me straight away looking at its system or block diagram was its what Tesla call AC/DC pin sharing and how the onboard charger is directly connected to what can be a DC input as well as AC.

Now reading on Tesla actually state this:

"With shared pins, the system must be designed to avoid connecting the battery pack to an AC electrical grid, which may result in high severity failures of grid and battery components. This section outlines an example safety analysis used to generate system design and requirements to avoid this failure mode."

Then it goes on with hazard and risk assessments that I won't bore people with here.

Then this section:

"Tesla’s implementation has the AC input of the on-board charger directly connected to the fast charge link. With this implementation DC high voltage will be applied to the AC input of the on-board charger whenever DC fast charging is active. The on-board charger must be designed to withstand this DC voltage and must not attempt to convert power when DC fast charging is active to avoid damage to the on-board charger power converters. The maximum DC voltage that the on-board charger must withstand can be derived as the greater of maximum pack voltage and maximum voltage seen during the DC charging external isolation check. If the on-board charger cannot meet this voltage withstand requirement, an alternative option is to separate the on-board charger from the fast charge link using relays or contactors. Failure modes of DC EVSEs must also be considered when choosing the maximum withstand voltage. Tesla has encountered situation where DC EVSEs applied higher than expected DC voltage duringexternal isolation testing, caused either by vehicle or EVSE malfunctions, resulting in damage to the on-board charger or other components connected to the fast charge link. An example of this is EVSEs rated for maximum voltage supported by the CCS standard unexpectedly applying this maximum voltage to a vehicle advertising it does not support this range. While it is not required to ensure there is no damage to components due to this failure mode, manufacturers should consider this malfunction when designing the system and at minimum ensure the failure is contained and does not pose safety hazards."

So by designing NACS the way they have and not keep AC and DC on separate wires IMHO as a design engineer they have made it more complicated by bringing in more components needed to make their system work. Hell if I am honest it's a big red flag for me and I would love to hear say the SAE's interpretation of it down at the component level.

But this is just all my opinion of course.

 

[Vostok]

Hell if I am honest it's a big red flag for me and I would love to hear say the SAE's interpretation of it down at the component level.

Yep it’s a big red flag for me too. Folks in the USA keep banging on about how “superior” the TPC is in every respect and how everything else is a “Frankenplug” that was specifically and deliberately designed to slow down EV adoption . And then they think USA == World and so they think the TPC should be adopted worldwide .

The biggest failings of the TPC, and they are not minor, are:

1. AC and DC pins not kept separate
2. Does not support 3 phase AC

No amount of American exceptionalism and sophistry can overcome that.

 

[[Zombie]]

At the end of the day USA can do what it wants, as they always have and always will.

It won't make any difference to us, because CCS2 has already won. Both here and in Europe.

 

[moa999]

Obviously it needs a mechanical switch inside it. But arguably that's not different to an isolator which will be in all EVs. Rather than on/off it's AC/DC.

Similar to the many legacy automakers still wanting a dedicated button for each function rather than Tesla's approach.

 

[cafz]

Tesla has encountered situation where DC EVSEs applied higher than expected DC voltage duringexternal isolation testing, caused either by vehicle or EVSE malfunctions, resulting in damage to the on-board charger or other components connected to the fast charge link. An example of this is EVSEs rated for maximum voltage supported by the CCS standard unexpectedly applying this maximum voltage to a vehicle advertising it does not support this range.

I wonder if this was the "ABB Ultrafast chargers can fry Model X charge ports" issue from a few years back (2019?). It affected the Chargefox Ultrafast sites that used ABB units.

 

[TrevRex]

Obviously it needs a mechanical switch inside it. But arguably that's not different to an isolator which will be in all EVs. Rather than on/off it's AC/DC.

Similar to the many legacy automakers still wanting a dedicated button for each function rather than Tesla's approach.

Ok I maybe should have explained it better.

The onboard charger will be hit with AC or DC. But like Tesla says

"With shared pins, the system must be designed to avoid connecting the battery pack to an AC electrical grid, which may result in high severity failures of grid and battery components. This section outlines an example safety analysis used to generate system design and requirements to avoid this failure mode."

Now there are a set of relays (+ and -) that run in parallel to the onboard charger ie if DC sensed close relays and go to battery.

BUT and this is a big BUT IMHO is those relays are for example welded closed which is entirely possible AC can be sent straight to the battery with the consequences mentioned above by Tesla.

Now Tesla have implemented what they call Fast Charge Contactor Weld Detection and state:

"Tesla’s implementation of fast charge contactor weld detection compares differential and common-mode DC voltages sensed on either side of the contactors. If the differential or common mode voltage matches, the fast charge contactor is diagnosed as welded. If a similar weld detection strategy is used, the detection should be designed to trigger only when DC voltage is present, as AC voltage waveforms seen while AC charging may cross DC voltage match thresholds for brief periods. Hardware or software filtering and/or AC/DC component detection of the fast charge link voltage can be used to mitigate this concern. Tesla has additionally encountered AC EVSEs that apply AC voltage with DC offset with or without the EVSE relays closed which may trigger voltage match detection. This can be caused by devices with in the EVSE used for insulation monitoring, weld detection, residual current detection, or other functions. An example of one such device is the Bender RCMB613, which partially conducts the AC voltage waveform through diodes in its residual current detection circuit."

I would still love to see an independent organisation's interpretation of this added complication and all failure modes tested besides my own opinion of course.

 

[LWI]

How is the shared NACS pins for AC and DC different from our EU Mennekes connector which also shares its pins between AC (single or 3 phase) and DC? Why is NACS worse?

 

[cafz]

How is the shared NACS pins for AC and DC different from our EU Mennekes connector which also shares its pins between AC (single or 3 phase) and DC? Why is NACS worse?

The standard Mennekes connector doesn't share contacts between AC and DC - in fact it's AC-only. The CCS2 standard that extends Mennekes also doesn't share power contacts between AC and DC - it shares signalling contacts, but the DC power contacts are separate from the AC power contacts.

The extended "Tesla Mennekes" connector on EU / AU delivered Model X and Model S does share power contacts between AC and DC power, and in this respect it's similar to NACS.

I don't agree that this issue is some kind of NACS blunder - yes, it adds complexity to the car circuitry, but this is a deliberate choice to enable a more ergonomic plug form factor. Human interface issues like this are important.

I wouldn't want to change our vehicles from CCS2, though - the three phase issue is relevant here.

 

[RichardV]

The standard Mennekes connector doesn't share contacts between AC and DC - in fact it's AC-only. The CCS2 standard that extends Mennekes also doesn't share power contacts between AC and DC - it shares signalling contacts, but the DC power contacts are separate from the AC power contacts.

The extended "Tesla Mennekes" connector on EU / AU delivered Model X and Model S does share power contacts between AC and DC power, and in this respect it's similar to NACS.

I don't agree that this issue is some kind of NACS blunder - yes, it adds complexity to the car circuitry, but this is a deliberate choice to enable a more ergonomic plug form factor. Human interface issues like this are important.

I wouldn't want to change our vehicles from CCS2, though - the three phase issue is relevant here.

Technically it is specified in a standard, IEC 62196-2, which allows for DC on the type 2 connector. Tesla were the only ones in practice to utilise this in EU and AU/NZ (and maybe a few other places) and even then they exceeded the max current stipulation.

Type 2 connector - Wikipedia

en.m.wikipedia.org

 

[Zoltrix77]

Technically it is specified in a standard, IEC 62196-2, which allows for DC on the type 2 connector. Tesla were the only ones in practice to utilise this in EU and AU/NZ (and maybe a few other places) and even then they exceeded the max current stipulation.

View attachment 946483

Type 2 connector - Wikipedia

en.m.wikipedia.org

I was just about to mention this myself. Wasn't there some talk of the Tesla implementation having a deeper port and connections (so providing backwards compatibility) than IEC 62196 to provide the extra current?

As others have said though, in the end, I am perfectly happy with the Type 2 / CCS2 we have ended up with.

 

[Zoltrix77]

Ok I maybe should have explained it better.

The onboard charger will be hit with AC or DC. But like Tesla says

"With shared pins, the system must be designed to avoid connecting the battery pack to an AC electrical grid, which may result in high severity failures of grid and battery components. This section outlines an example safety analysis used to generate system design and requirements to avoid this failure mode."

Now there are a set of relays (+ and -) that run in parallel to the onboard charger ie if DC sensed close relays and go to battery.

BUT and this is a big BUT IMHO is those relays are for example welded closed which is entirely possible AC can be sent straight to the battery with the consequences mentioned above by Tesla.

Now Tesla have implemented what they call Fast Charge Contactor Weld Detection and state:

"Tesla’s implementation of fast charge contactor weld detection compares differential and common-mode DC voltages sensed on either side of the contactors. If the differential or common mode voltage matches, the fast charge contactor is diagnosed as welded. If a similar weld detection strategy is used, the detection should be designed to trigger only when DC voltage is present, as AC voltage waveforms seen while AC charging may cross DC voltage match thresholds for brief periods. Hardware or software filtering and/or AC/DC component detection of the fast charge link voltage can be used to mitigate this concern. Tesla has additionally encountered AC EVSEs that apply AC voltage with DC offset with or without the EVSE relays closed which may trigger voltage match detection. This can be caused by devices with in the EVSE used for insulation monitoring, weld detection, residual current detection, or other functions. An example of one such device is the Bender RCMB613, which partially conducts the AC voltage waveform through diodes in its residual current detection circuit."

I would still love to see an independent organisation's interpretation of this added complication and all failure modes tested besides my own opinion of course.

I don't think this has been any issue in practice though as it has been proven in NACS Tesla's over 10 years.

 

[Zoltrix77]

What I would be concerned about in North America is whether the TPC will ever be capable of V2X. It’s not exactly in Tesla’s interests to support V2X since they have Powerwalls to sell and Elon has trash-talked V2X on a number of occasions. So have Ford and GM locked themselves into a roadmap they no longer have input into?

Sure CCS2 doesn’t support V2X yet - but it is planned to in 2025.

I highly doubt the NACS connector would be an issue with V2x, it is afte rall just a connector. V2x would be governed by the protocol. I also doubt Ford would want the V2G of the F150 to be useless going forward.

Everything is still up in the air however, rumors that NACS will just be a 2nd connector on the car is one such. I personally don't believe this as you would need you another contactor based system to ensure high voltages do not appear in the 2nd charge port pins during charging, even more cost and complexity.

 

[Zoltrix77]

Anyone interested, can't believe I missed this months ago:

https://tesla-cdn.thron.com/static/...ndard-Technical-Specification-TS-0023666.pdf"

Some interesting points:

- specifically mentions that NACS *can* do V2X, just I thought, connector has zero to do with V2X

- 500v and 1000v versions of the connector, backwards compatible with both inlet/outlet and outlet/inlet. (could be taken as a clue that Tesla will release 1000v vehicles or could just allow for it to please other manufacturers who wish to use the connector at 1kV)

- is using the same communications protocol as CCS (this could still mean that Tesla uses their own proprietary CAN signaling when a Tesla vehicle is talking to a Tesla Supercharger to allow the superfast negotation we are all used to).


After reading around other forums, ist appears plenty of people have no idea of the difference between the connector and the access to the supercharger network. 2 totally different issues. I am for one interested what Ford does outside of North America in regards whether or not that will seek a Supercharger access agreement.

 

[RichardV]

Anyone interested, can't believe I missed this months ago:

https://tesla-cdn.thron.com/static/HXVNIC_North_American_Charging_Standard_Technical_Specification_TS-0023666_HFTPKZ.pdf?xseo=&response-content-disposition=inline;filename="North-American-Charging-Standard-Technical-Specification-TS-0023666.pdf"

...
- is using the same communications protocol as CCS
...

So just a visual on why CCS1 vs NACS is just a form factor issue, (CCS2 similar again but different form factor again).

Same five pins, just in a different form/positioning.
So slapping a NACS cable on a non-tesla DC fast charger is a trivial exercise. And it won't give you better reliability. That will still require an improvement in engineering and maintenance schedule.

 

[cafz]

So slapping a NACS cable on a non-tesla DC fast charger is a trivial exercise. And it won't give you better reliability. That will still require an improvement in engineering and maintenance schedule.

Well, it will improve reliability in one way - that fragile clip at the top of the CCS1 plug doesn't have an equivalent on the NACS one, it's locked by the car as in CCS2.

 

[TrevRex]

I don't agree that this issue is some kind of NACS blunder - yes, it adds complexity to the car circuitry, but this is a deliberate choice to enable a more ergonomic plug form factor. Human interface issues like this are important.

If Tesla was doing this as "a deliberate choice to enable a more ergonomic plug form factor" I would submit there was a already an existing system that provides that function without the failure mode complexity of AC/DC pin sharing using CHAdeMO for fast charging etc, ie keep AC/DC totally separate in individual ports that are "ergonomic" to use individually.

 

[moa999]

what Ford does outside of North America in regards whether or not that will seek a Supercharger access agreement.

Most likely it means that future Ford models will have the CCS2 port in the preferred spot (back left/ front right) so they won't use up extra spots)

And possibly means better access (ie. All existing chargers v some, plug and charge billing, and maybe Tesla pricing)

 

[[Zombie]]

a more ergonomic plug form factor

CHAdeMO

Have you seen the size of a CHAdeMO plug?

 

[TrevRex]

Have you seen the size of a CHAdeMO plug?

I guess that port on my Mitsubishi PHEV that I can plug in easily gives me no opinion that's worth providing.

 

[[Zombie]]

no opinion that's worth providing

I didn't say that. But you're definitely the first person I've met that refers to CHAdeMO as ergonomic. Very interesting.