Are J1772 AC contacts tolerant of HV DC?

[Jaime]

It occurred to me that once Tesla opens up their Supercharger network to others, someone may unknowingly attempt to use a Level 2 Tesla adapter. If communication occurs on the lower J1772 pins, the car will talk to the charger, and it may possibly apply DC to the AC pins. I hope the chargers are smart enough to prevent this.

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[bub]

I'm sure they've considered this possibility.

A guess for a safety mechanism. After communication to initiate a charge from the L3 charger and the car. The L3 charger probably reads the voltage on the DC line coming from the car's battery before applying current. If that's how it works, then the L3 charger would not see anything coming from the battery and would not put out any DC power.

 

[Heliian]

I would certainly hope so.

 

[duncanmaio]

I certainly hope it's impossible to harm person or property with the wrong adapter (and I lack the knowledge to explain how it is impossible). The transition to NACS is going to be confusing for drivers, who will undoubtedly face loads of misinformation.

 

[Amps]

I certainly hope it's impossible to harm person or property with the wrong adapterI lack the knowledge to explain how it is impossible

When Tesla opened up their standard and posted the original NACS documents, there was a technical drawing showing how it differentiated between various conditions. They have pulled that document and it now refers to the $195.00 SAE J3400 standard document.

The NACS AC/DC Pin Sharing Appendix is still available:

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.

https://digitalassets.tesla.com/tes...-Charging-Standard-AC-DC-Pin-Sharing-Appendix

 

[Etsquared]

It occurred to me that once Tesla opens up their Supercharger network to others, someone may unknowingly attempt to use a Level 2 Tesla adapter. If communication occurs on the lower J1772 pins, the car will talk to the charger, and it may possibly apply DC to the AC pins. I hope the chargers are smart enough to prevent this.

Had a short experience with multiple public “Tesla” chargers available to my XLT. All were Level 2, first one I used worked on a Leviton adapter truck got full charge that. Then too many neighbors rightly complained that they didn’t want to buy the adapter so community changer out plug/cable assembly and it’s back ToJ1772. Multiple other times at different community chargers the Tesla plug NACS plug was left on and my Leviton charger adapter NEVER WORKS. I think it is a setting in the charger itself. From my experience that’s all it could be

 

[Maquis]

When Tesla opened up their standard and posted the original NACS documents, there was a technical drawing showing how it differentiated between various conditions. They have pulled that document and it now refers to the $195.00 SAE J3400 standard document.

The NACS AC/DC Pin Sharing Appendix is still available:

https://digitalassets.tesla.com/tes...-Charging-Standard-AC-DC-Pin-Sharing-Appendix

That describes connecting the vehicle’s HVB to incoming AC. The question on this thread is the opposite condition - sending DC from the fast charger to the AC input of the onboard charger. This condition may also be covered in that standard. I have to believe this possibility has been accounted for.

 

[Maquis]

Had a short experience with multiple public “Tesla” chargers available to my XLT. All were Level 2, first one I used worked on a Leviton adapter truck got full charge that. Then too many neighbors rightly complained that they didn’t want to buy the adapter so community changer out plug/cable assembly and it’s back ToJ1772. Multiple other times at different community chargers the Tesla plug NACS plug was left on and my Leviton charger adapter NEVER WORKS. I think it is a setting in the charger itself. From my experience that’s all it could be

The latest generation destination chargers can be configured to “Tesla-only” mode. Although some have reported that if you connect the adapter to the charger first, wait 30 seconds, then plug in to the vehicle. I haven’t tried it.

 

[Amps]

The question on this thread is the opposite condition - sending DC from the fast charger to the AC input of the onboard charger. This condition may also be covered in that standard. I have to believe this possibility has been accounted for.

Both conditions and AC/DC differentiation are covered in the linked appendix and Section 4 of the original NACS document.

Added:

K3 and K4 are contactors used to control the connection of the vehicle battery to the charging station. K3 and K4 are closed during DC charging and open during AC charging.

 

[Etsquared]

The latest generation destination chargers can be configured to “Tesla-only” mode. Although some have reported that if you connect the adapter to the charger first, wait 30 seconds, then plug in to the vehicle. I haven’t tried it.

Will try today and report

 

[Pioneer74]

The latest generation destination chargers can be configured to “Tesla-only” mode. Although some have reported that if you connect the adapter to the charger first, wait 30 seconds, then plug in to the vehicle. I haven’t tried it.

I think that only works with the TeslaTap. They have a chip in it to fool the charger into thinking whatever plugs in is a Tesla.

 

[flyct]

Will try today and report

I have latest generation 3 Tesla chargers at 2 homes.

Commisioning set up offers 3 modes. All Vehicles, Only Tesla and ONLY Authorized Tesla vehicles by VIN number.

It sucks if someone set it up for only Tesla. I leave mine set to all vehicles. If I’m not home and someone needs an emergency charge they can use my Tesla charger. I even keep a Tesla to J1772 adaptor there if needed for other than Tesla EVs.

Our cabin is in a gated community in a very remote area of Florida. I helped out a Bolt driver who limped into the guard gate. The guard called me and I had the nice polite elderly lady come to my cabin and plug in for a few hours so she could get enough charge to get to the nearest DC fast charger.

We EV owners need to stick together.

 

[Etsquared]

I have latest generation 3 Tesla chargers at 2 homes.

Commisioning set up offers 3 modes. All Vehicles, Only Tesla and ONLY Authorized Tesla vehicles by VIN number.

It sucks if someone set it up for only Tesla. I leave mine set to all vehicles. If I’m not home and someone needs an emergency charge they can use my Tesla charger. I even keep a Tesla to J1772 adaptor there if needed for other than Tesla EVs.

Our cabin is in a gated community in a very remote area of Florida. I helped out a Bolt driver who limped into the guard gate. The guard called me and I had the nice polite elderly lady come to my cabin and plug in for a few hours so she could get enough charge to get to the nearest DC fast charger.

We EV owners need to stick together.

We do need to stick together as EV owners, also blissfully retired, my lightning was a retirement gift from my wife. Up north ( in Orlando) our community is quite enthusiastic about EV. That was very kind what you did for the bolt

 

[flyct]

We do need to stick together as EV owners, also blissfully retired, my lightning was a retirement gift from my wife. Up north ( in Orlando) our community is quite enthusiastic about EV. That was very kind what you did for the bolt

ET,

I love it. Another Floridian who is "Blissfully Retired" There are a few of us retired people in Florida.

We picked up my wife's Tesla in Orlando on John Young Pkwy about a year ago.

Our remote cabin is about 15 miles south of Yeehaw Junction on 441. You don't want to run out of juice there. https://ihammock.net/ https://www.youtube.com/@indianhammock

 

[Maquis]

I think that only works with the TeslaTap. They have a chip in it to fool the charger into thinking whatever plugs in is a Tesla.

The person reporting this was indeed using a TT.

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