Best Way To Install Car Charger with PowerWalls?

[arnolddeleon]

Edit: I guess it does say "Any Wall Connector"

Yes, I don't know if it was intentional to emphasize the Tesla products (by using the term "wall connector" which is not an industry standard term in my opinion) or it was the unintentional effect of trying to use "lay" terms to explain things. Tesla doesn't need any cooperation from the EVSE to make this work with their cars. On the other hand if the EVSE was involved then it can work with any car.

 

[btpots]

Hi @Vines

Thank you so much for your reply.

If it helps explain my install, here’s the wiring diagram showing the 125A backup load center to which that licensed electrician said he can connect the Juicebox 40. I had called the Tesla Solar system HelpDesk after I got his quote and plan to check if that voids the Tesla warranty and was told that it would not.

But any insight here would help.

@Vines Does the wiring diagram that I uploaded help explain my setup and question.

 

[Vines]

@Vines Does the wiring diagram that I uploaded help explain my setup and question.

What you are proposing with the EVCS would be a technical violation of 705.12, since it probably has a label on it saying

Also, if the Powerwalls were set to grid charge, while the car was charging it would overload the 100A feeder conductor most likely.

Finally I do not really understand what is happening here:

It appears the PW Generation subpanel is connected inside the MSP with some kind of tap? Maybe they used the factory line side tap location that some combo panels have, to backfeed solar into the bus, then used it for the PW Generation subpanel? Seems a bit questionable, and I'd probably go to the MSP with my new EV circuit.

 

[arnolddeleon]

What you are proposing with the EVCS would be a technical violation of 705.12, since it probably has a label on it saying
View attachment 944278

Also, if the Powerwalls were set to grid charge, while the car was charging it would overload the 100A feeder conductor most likely.

Finally I do not really understand what is happening here:

View attachment 944280

It appears the PW Generation subpanel is connected inside the MSP with some kind of tap? Maybe they used the factory line side tap location that some combo panels have, to backfeed solar into the bus, then used it for the PW Generation subpanel? Seems a bit questionable, and I'd probably go to the MSP with my new EV circuit.

It looks to me like it connected through the Tesla backup switch. I'm guessing that's where "the magic" in the backup switch occurs. The main panel connection to the meter base doesn't need to be tapped. It's effectively tapped through the meter base/backup switch.

FWIW when Tesla installed my first Powerwalls they moved a load circuit that was effectively on sub panel where one of my existing (non-Tesla) PV system was. I think it just made easier for the designers to make sure that things were designed correctly. Basically they didn't want a load on the "generation" side of the design.

Basically I will amend my caution about adding loads to the generation panel to recommend against doing it. Clever things often end asking for trouble down the line.

 

[Vines]

It looks to me like it connected through the Tesla backup switch. I'm guessing that's where "the magic" in the backup switch occurs. The main panel connection to the meter base doesn't need to be tapped. It's effectively tapped through the meter base/backup switch.

FWIW when Tesla installed my first Powerwalls they moved a load circuit that was effectively on sub panel where one of my existing (non-Tesla) PV system was. I think it just made easier for the designers to make sure that things were designed correctly. Basically they didn't want a load on the "generation" side of the design.

Basically I will amend my caution about adding loads to the generation panel to recommend against doing it. Clever things often end asking for trouble down the line.

The backup switch certainly occurs here but this tap is between the backup and the main breaker. I suspect this might be using something like this:
SR69064A Terminal Kit for Solar Ready CSED, Installation Instructions | Schneider Electric

The backup switch has no AC connections to attach any branch circuits to, so this is some kind of wire, or bus tap.

 

[btpots]

What you are proposing with the EVCS would be a technical violation of 705.12, since it probably has a label on it saying
View attachment 944278

Also, if the Powerwalls were set to grid charge, while the car was charging it would overload the 100A feeder conductor most likely.

Finally I do not really understand what is happening here:

View attachment 944280

It appears the PW Generation subpanel is connected inside the MSP with some kind of tap? Maybe they used the factory line side tap location that some combo panels have, to backfeed solar into the bus, then used it for the PW Generation subpanel? Seems a bit questionable, and I'd probably go to the MSP with my new EV circuit.

@Vines thanks for the clarification. Besides that, the fact that none of the other electricians gave me that option tells me to stick to the EV drawing power from the MSP.

 

[Vines]

Yes, I don't know if it was intentional to emphasize the Tesla products (by using the term "wall connector" which is not an industry standard term in my opinion) or it was the unintentional effect of trying to use "lay" terms to explain things. Tesla doesn't need any cooperation from the EVSE to make this work with their cars. On the other hand if the EVSE was involved then it can work with any car.

This is really great to know, thanks for the clarification.

 

[Jonathan Mason]

Hi. I'm hoping for insight to what I think is a similar situation as described in this thread.
I had a solar system and TESLA Powerwall installed 12 months ago. all works perfectly, no issues.
I then had a separate electrician install a TESLA Wall Charger 3 months ago, which also works perfectly fine on its own.

The trouble is the TESLA app doesn't seem to like the data when my TESLA MODEL S is being charged. It does some weird stuff in the app by moving the current load from HOME to EV, and not showing the correct amount of load in EV.

TESLA tech support are non existent, so my electrician is scratching his head. He think another CT clamp is required somewhere... The Wall Charger was installed just on the house side of the main meter box, before the backup gateway and Powerwall.

Any ideas?
Thanks, J.

 

[Vines]

Hi. I'm hoping for insight to what I think is a similar situation as described in this thread.
I had a solar system and TESLA Powerwall installed 12 months ago. all works perfectly, no issues.
I then had a separate electrician install a TESLA Wall Charger 3 months ago, which also works perfectly fine on its own.

The trouble is the TESLA app doesn't seem to like the data when my TESLA MODEL S is being charged. It does some weird stuff in the app by moving the current load from HOME to EV, and not showing the correct amount of load in EV.

TESLA tech support are non existent, so my electrician is scratching his head. He think another CT clamp is required somewhere... The Wall Charger was installed just on the house side of the main meter box, before the backup gateway and Powerwall.

Any ideas?
Thanks, J.

If your car charger was installed before the backup gateway, then the Tesla system cannot monitor it unless some CT's are added at the initial installation. If that car charger didn't exist at the time there is no reason to think Tesla would have added the needed CT's.

Likely someone needs to either Add sone CT's to capture this additional load, or reconfigure the car charger to be part of the backup circuit as Tesla recommends.

A Third option is to connect the car charger to the non-backup lugs of the Gateway 2, and add a means of overcurrent protection as required by the installation manual.

 

[h2ofun]

If your car charger was installed before the backup gateway, then the Tesla system cannot monitor it unless some CT's are added at the initial installation. If that car charger didn't exist at the time there is no reason to think Tesla would have added the needed CT's.

Likely someone needs to either Add sone CT's to capture this additional load, or reconfigure the car charger to be part of the backup circuit as Tesla recommends.

A Third option is to connect the car charger to the non-backup lugs of the Gateway 2, and add a means of overcurrent protection as required by the installation manual.

For me, who cares about all the this stuff. I just use it now!!!!!! One can truly over think this, which is why I tell works putting this stuff in place is not a zero effort thing for some folks