How does Plug and Charge work technically?

[CHP]

Hi, I have/had multiple problems with my Macans which somehow seem to be related to possibly faulty super charger. I wonder how plug and charge work? I assume car itself is to far away for RF so there must be a physical connection for authentication.

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[jwatte]

Yes, there is signaling over the actual connection wire. This signaling lets the ground station ask "who are you" of the car, and it can then check it its upstream computers if the "you" is allowed. Once it's OK, there's a second cryptographic step of "prove it" that involves provisioning certificates in the car itself, so it's hard to try to "clone" the information from a car to try to steal someone else's charging information.

If you have fast charging problems where the problems are all about "starting to charge in the first place," or maybe "billing doesn't work right," it's possible that plug-and-charge might be involved. If you have fast charging problems that are different (slow speed, sudden disconnects, charger not recognized, etc) then it's less likely to be plug-and-charge involved.

 

[CHP]

Yes, there is signaling over the actual connection wire. This signaling lets the ground station ask "who are you" of the car, and it can then check it its upstream computers if the "you" is allowed. Once it's OK, there's a second cryptographic step of "prove it" that involves provisioning certificates in the car itself, so it's hard to try to "clone" the information from a car to try to steal someone else's charging information.

If you have fast charging problems where the problems are all about "starting to charge in the first place," or maybe "billing doesn't work right," it's possible that plug-and-charge might be involved. If you have fast charging problems that are different (slow speed, sudden disconnects, charger not recognized, etc) then it's less likely to be plug-and-charge involved.

Thank you so much for your detailed response. Just wonder if broken cable or malfunctioning charger could corrupt or even worse, damage cars internals?
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[PrudentOcean]

If everything is working as it should then electrical damage shouldn’t happen.

The EVSE and car negotiate the charging voltage and current using a low-voltage signaling protocol. Currents that con potentially damage electronics aren’t supposed to flow until both sides agree on the charging parameters.

 

[CHP]

Thank you very much, that narrows it down and kind of fits with latest drive system fault starting immediately after initiating charging. Plug and Charge wasn't working anymore (worked until initial incidence) so I had to use RF card. Plugged in the cable and upon opening door I saw red circle of death. I got an invoice so power was delivered until I aborted and disconnected.

This was not a faulty charger though, I had two incidents with two Macans on assumed faulty charger (same charger model) due to damaged cables (design error as cable to short, they got bended and damaged internal cable cooling according to Porsche, one confirmed and out of service). First (charger now out of service) didn’t allow to disconnect and second showed error after charging on a) my car and b) charger while charging next car (Taycan). This all happened at same Porsche centre.

 

[CHP]

Since you are extremely knowledgeable, may I please ask an other question. How does Porsche itself abort charging. At home, I can press the illuminated button at the Porsche charger port and charging is terminated. You mentioned low-voltage signal protocol for initiating high voltage high current charging. I think terminating high voltage charging (manually or automatically by Macan as desired battery percentage reached) may be the stage where things went wrong due to faulty cables. Would this make sense?

 

[PrudentOcean]

It seems conceivable that a faulty connection that prevented a "stop charging" signal from being sent to the charger would allow the EVSE to continue to deliver current after your charging target was reached.

But being a software engineer I would expect there to also be some periodic keep-alive to be sent that lets both parties know that everything is normal. If that wasn't received I would expect the charging session to be ended.

 

[CHP]

It seems conceivable that a faulty connection that prevented a "stop charging" signal from being sent to the charger would allow the EVSE to continue to deliver current after your charging target was reached.

But being a software engineer I would expect there to also be some periodic keep-alive to be sent that lets both parties know that everything is normal. If that wasn't received I would expect the charging session to be ended.

Thank you very much. Based on information provided by you, I was able to find relevant documents. All your assumptions are correct. We use CCS Type 2 in Europe. There are 2 designated pins. The proximity pilot (PP) pin verifies the physical connection and identifies the charging cable's maximum current capacity, while the control pilot (CP) pin manages communication for charging, such as status, safety, and power negotiation. The PP is a safety signal to ensure the plug is physically in place, while the CP acts as the main communication line, coordinating the entire charging sequence from start to finish.

Porsche technician and I were in the car while charging, there was no fault and charging stopped at 80%. Porsche technician removed plug, there was no error on either my car or charger. I locked my car and came back after app. 5 minutes. Upon opening, I was greeted with red circle drive system failure and the charger showed a red light while charging the next car (Taycan). I assume, initiating charging of Taycan would not have been possible if fault was present from the start. Charging was done via Porsche RF card so I don't have any information if charging was registered correctly. Porsche is very quiet about this and basically rules out charger as cause.

I would assume a simple software miscommunication via CP would have resulted in an error notification. Further, Plug and charge no longer worked (2 days later) at other non Porsche charger (used before). Charging was possible via RF car but resulted in red circle drive system failure.

With red circle drive system failure clearing after restart, I assume fault is triggered by activating Macan's CP communication software/hardware.

 

[de0xyrib0se]

Is the system error *after* charging (cable disconnected), *after* charging (cable connected), or during charging?

Even if the comm cable is damaged during charging the vehicle can abort the charge by simply disconnecting the internal contactor. This is comm protocol independent. The system can abort a charge at any point, even if the charger has not agreed to it!

There are multiple layers of protection that assume all possible conditions otherwise you'd go into a runaway charge simply because the charging station doesnt agree with the request (for whatever reason).

 

[CHP]

Is the system error *after* charging (cable disconnected), *after* charging (cable connected), or during charging?

Even if the comm cable is damaged during charging the vehicle can abort the charge by simply disconnecting the internal contactor. This is comm protocol independent. The system can abort a charge at any point, even if the charger has not agreed to it!

There are multiple layers of protection that assume all possible conditions otherwise you'd go into a runaway charge simply because the charging station doesnt agree with the request (for whatever reason).

здрасти! (my wife is from Sofia and my name is Chris as well ;-)). The error on my latest Macan did occur when returning to the car after charging (cable disconnected) with super charger (now charging neighbouring car) showing red light indicating fault. Previous Macan wouldn't disconnect for a few minutes showing red-light next to connected cable on my car. Porsche technician used some force to disconnect.

I also would assume there are certain levels of safety protocols in place, it's high voltage and high current after all. In case of irregularities or protocol violation, either car or charger should terminate connection immediately. Car was charged normally to agreed 80%, no fault on either car or charger while disconnecting. My car aside, why would charger now show red light while charging Taycan. There seems to be an intermittent fault assuming Porsche technician would not have started/being able charging Taycan if red light was on.

With drive system fault error (I hope false positive) reoccurring while charging and loss of Plug and Charge, it seems CP comm on my car is/was corrupted. Whether due to software or hardware, I have no idea. I just hope CP comm pin (on my Car) is surge protected or surge protection worked in my case.

 

[de0xyrib0se]

здрасти! (my wife is from Sofia and my name is Chris as well ;-)). The error on my latest Macan did occur when returning to the car after charging (cable disconnected) with super charger (now charging neighbouring car) showing red light indicating fault. Previous Macan wouldn't disconnect for a few minutes showing red-light next to connected cable on my car. Porsche technician used some force to disconnect.

I also would assume there are certain levels of safety protocols in place, it's high voltage and high current after all. In case of irregularities or protocol violation, either car or charger should terminate connection immediately. Car was charged normally to agreed 80%, no fault on either car or charger while disconnecting. My car aside, why would charger now show red light while charging Taycan. There seems to be an intermittent fault assuming Porsche technician would not have started/being able charging Taycan if red light was on.

With drive system fault error (I hope false positive) reoccurring while charging and loss of Plug and Charge, it seems CP comm on my car is/was corrupted. Whether due to software or hardware, I have no idea. I just hope CP comm pin (on my Car) is surge protected or surge protection worked in my case.

Здравей!

I wouldnt shrug off a drive system fault, especially if it came up after charging is finished and the cable is disconnected.

If its recurring definitely have the dealer run diagnostics. Errors recorded should give a hint what caused the error in the first place.

I have seen charging errors due to malfunctioning chargers but never a drive system error. Not saying it isnt possible for a charger to cause one, but to cause it while it is disconnected is highly unlikely!

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