Plug in J1772 adapter first -- or connect adapter to charger first?

[davewill]

I wonder whether all of this is working right now on the Tesla? I remember a few years ago when I unplugged quickly I’d get some nice long arcs since the power pins were still energized, lol. The standard is supposed to provide the means to prevent this arcing when properly implemented.

What is supposed to happen is that when the button is pressed, the car stops drawing current within a small number of milliseconds. That is to prevent arcing both at the handle and at the relays in the EVSE. It is not necessary for the car to actually signal that power should be removed when the button is pressed and my LEAF did not do so, but Teslas and most other cars do.

I've heard of enough of these arcing complaints that I've wondered for a while whether Tesla is shutting down the power draw quickly enough

 

[ewoodrick]

Hi all,

I have a new Model 3 and my wife has a different non-Tesla EV which we purchased first. So we have a J1772 Level 2 home charger. I've been attaching the Tesla adapter to the charger and then putting that assembly into the Tesla charging port. (I've done that twice now with no issues.) I see now that in the owner's manual it says to put the adapter into the charging port first and then inserting the J1772 charger. I'll do it that way from now on, but does the order really matter?

Thanks.

Can you say where that is in the manual?

About the only thing that I can find is

• Tesla also offers adapters that allow you to plug into the most commonly used public charging stations in your region. At a public charge station, first attach the adapter to the station's charging connector and then plug in your vehicle.

and

To disconnect the charge cable when using an adapter at a public charge station:

1. Unlock Model 3.
2. While holding the public charging handle in one hand and the adapter in the other hand, press and hold the button on the public charging handle and pull both outwards, removing the handle and adapter at the same time.
   Note: Press and hold the button on the charging handle again to release the adapter from the public charging handle.
   If the charging station handle separates from the adapter, leaving the adapter in Model 3, use the touchscreen to unlock the charge port.
   
   

These suggest to me to put the adaptor on the cable first and not the car.

It IS IMPORTANT when removing the plug that you press the handle first and wait for charging to complete and the charge port to unlock.
On the J-1772, it is possible to press and pull the handle from the adaptor before charging has completed, leaving the contacts live with possible arcing.

 

[AlanSubie4Life]

I've heard of enough of these arcing complaints that I've wondered for a while whether Tesla is shutting the power draw quickly enough

Yeah it's been years, and I'm not going to try again, since sometimes the car didn't like it when it happened. Might be fixed now, who knows...

Certainly seems like it should be easy to do assuming the J-1772 physical latch holding it to the adapter isn't snapped off, which happens.

 

[davewill]

On the J-1772, it is possible to press and pull the handle from the adaptor before charging has completed, leaving the contacts live with possible arcing.

As noted above, it's not supposed to be.

 

[MAPekala]

Can you say where that is in the manual?

About the only thing that I can find is

• Tesla also offers adapters that allow you to plug into the most commonly used public charging stations in your region. At a public charge station, first attach the adapter to the station's charging connector and then plug in your vehicle.

and

To disconnect the charge cable when using an adapter at a public charge station:

1. Unlock Model 3.
2. While holding the public charging handle in one hand and the adapter in the other hand, press and hold the button on the public charging handle and pull both outwards, removing the handle and adapter at the same time.
   Note: Press and hold the button on the charging handle again to release the adapter from the public charging handle.
   If the charging station handle separates from the adapter, leaving the adapter in Model 3, use the touchscreen to unlock the charge port.
   

These suggest to me to put the adaptor on the cable first and not the car.

It IS IMPORTANT when removing the plug that you press the handle first and wait for charging to complete and the charge port to unlock.
On the J-1772, it is possible to press and pull the handle from the adaptor before charging has completed, leaving the contacts live with possible arcing.

Here's where that is in the manual:

 

[ewoodrick]

As noted above, it's not supposed to be.

I'm talking about the physical latch that's on the J-1772 adapter and the safety latch that's in the car.

You can't pull the Tesla plug out until the safety latch has disengaged.

You can easily push and pull the J-1772 latch at the same time. AFIK, the Tesla adapter doesn't have any mechanism, except for the push latch to keep the plug from being withdrawn.

 

[davewill]

I'm talking about the physical latch that's on the J-1772 adapter and the safety latch that's in the car.

You can't pull the Tesla plug out until the safety latch has disengaged.

You can easily push and pull the J-1772 latch at the same time. AFIK, the Tesla adapter doesn't have any mechanism, except for the push latch to keep the plug from being withdrawn.

Yes, but Tesla shouldn't be allowing the car to draw power after you press the J1772 button, and I really don't think they do, but some people have seen arcing so...

 

[ewoodrick]

Yes, but Tesla shouldn't be allowing the car to draw power after you press the J1772 button, and I really don't think they do, but some people have seen arcing so...

That's my point! It is "possible" to press and pull so fast that the communications haven't had time to complete, and the inverters haven't turned off.

The CHAdeMO and CCS adapters also show some of the issue. CHAdeMO plugs, I believe, are infamous for having broken release buttons. Instantly disrupting 400A isn't a good thing.

 

[tga]

I 100% know, that the car knows, that a plug is plugged in but is dead because it has happened to me. One of the chargers died at work, I normally just plug in and walk away. My app told me that a plug is plugged in but not providing power warning message to me.

I oversimplified - the car knows if a WC or UMC plug is inserted without power, or a J1772 adapter + J1772 plug without power, but it does not know if an adapter only is inserted, which was the point of my post.

However, it can't detect the adapter if the plug is not in it as the proximity signal that is used must be connected through the handle.

Exactly.

The CHAdeMO and CCS adapters also show some of the issue. CHAdeMO plugs, I believe, are infamous for having broken release buttons. Instantly disrupting 400A isn't a good thing.

And DC is worse, since AC arcs are self extinguishing (at the zero crossing)

 

[RayK]

Yes, but Tesla shouldn't be allowing the car to draw power after you press the J1772 button, and I really don't think they do, but some people have seen arcing so...

Count me as one of those who has seen / heard arcing when pressing the J1772 handle's latch and pulling it out of the adapter (which remained in the car's port). Almost sh!t my pants when this happened. That quickly taught me to stop charging via the app before even touching the handle whenever using the J1772 adapter. This was at work where we had free charging from a 30A ChargePoint CT4000 over 5 years ago.

 

[stopcrazypp]

Here's where that is in the manual:

Interesting it says that when the CCS adapter manual says the opposite:
"Align the CCS Combo 1 Adapter to the end of the charging station’s cable and push together, ensuring it is firmly attached."
https://www.tesla.com/sites/default/files/CCS/CCS_Combo_1_Adapter_en-NA.pdf

 

[stopcrazypp]

Count me as one of those who has seen / heard arcing when pressing the J1772 handle's latch and pulling it out of the adapter (which remained in the car's port). Almost sh!t my pants when this happened. That quickly taught me to stop charging via the app before even touching the handle whenever using the J1772 adapter. This was at work where we had free charging from a 30A ChargePoint CT4000 over 5 years ago.

I looked this up, Tesla's are not the only ones with reported J1772 arcing. I looked up "J1772 arcing" and found examples from other brands.

One of the results pointed to the spec of the AC contactor disconnect being at 100ms after control pilot disconnect. and that there is a 14mm inset of the pins. That means 14cm/sec withdrawal speed to avoid arcing, a relatively slow speed. The argument is, as such, it's not actually to prevent arcing, but rather live contact exposure.
Stopping charging