Tesla wall connector question..

[a1machinista1]

Ok, I try to make this uncomplicated. (My wife is betting against me).
We currently have one 14-50 on a 50amp breaker. We charged our Model 3 for 2 1/2 yrs using the mobile connector.
We are waiting for a Model Y and a Model S. I can get two wall chargers and upgrade the 50 amp to a 60 amp breaker. Yes the wire will handle it. I had the electrician install heavy
(?Ga) when he did the 14-50.
OR I can keep the 14-50 for the Model S and have two 120v 20a breakers that I can use to get a 6-20 for the Model Y.
The Model Y will be charged to 80% nightly and the Model S will be charged to 90% nightly.
Thoughts?

 

[jcanoe]

How many miles per day, Monday through Friday, do you commute/drive the Model S/ What about on the weekend? How many miles per day do you anticipate driving the Model Y?

Will both the Model S and the Model Y be parked, charge in a home garage?

 

[jcanoe]

The automatic load balancing capability of the Tesla Wall Connector is currently in beta test. With automatic load balancing up to four Tesla Wall Connectors can share a single charging circuit. For your purpose two Tesla Wall Connectors could share a single circuit.

Change the junction box with the NEMA 14-50 receptacle to a sub panel. Install a 60A breaker at the service panel and (2) 60A breakers at the sub panel (one for each Wall Connector.) Without automatic loading balancing each Wall Connector would have to be installed on a 30A circuit, set as if it was on a 30A circuit (maximum of 24A for charging.) With automatic load balancing either of the two Wall Connectors could charge at the maximum for a 60A circuit (48A). When both Tesla vehicles are charging the maximum amperage for each Wall Connector would automatically be limited to 24A. If one Tesla vehicle completes charging sooner then the second Tesla vehicle would automatically continue, complete charging at 48A.

The Gen3 Wall Connector requires a Wi-Fi network to be able to use the automatic loading balancing capability.

 

[a1machinista1]

How many miles per day, Monday through Friday, do you commute/drive the Model S/ What about on the weekend? How many miles per day do you anticipate driving the Model Y?

Will both the Model S and the Model Y be parked, charge in a home garage?

Both will be parked in the same garage.
Model S will be driven 30-35k per year
YES YOU READ THAT RIGHT.
Model Y will definitely driven about 18k a year
Both cars will be used daily 7 days a week.

 

[a1machinista1]

The automatic load balancing capability of the Tesla Wall Connector is currently in beta test. With automatic load balancing up to four Tesla Wall Connectors can share a single charging circuit. For your purpose two Tesla Wall Connectors could share a single circuit.

Change the junction box with the NEMA 14-50 receptacle to a sub panel. Install a 60A breaker at the service panel and (2) 60A breakers at the sub panel (one for each Wall Connector.) Without automatic loading balancing each Wall Connector would have to be installed on a 30A circuit, set as if it was on a 30A circuit (maximum of 24A for charging.) With automatic load balancing either of the two Wall Connectors could charge at the maximum for a 60A circuit (48A). When both Tesla vehicles are charging the maximum amperage for each Wall Connector would automatically be limited to 24A. If one Tesla vehicle completes charging sooner then the second Tesla vehicle would automatically continue, complete charging at 48A.

The Gen3 Wall Connector requires a Wi-Fi network to be able to use the automatic loading balancing capability.

The current 14-50 already runs off of a 100amp sub panel from our 200a main panel.

 

[a1machinista1]

The automatic load balancing capability of the Tesla Wall Connector is currently in beta test. With automatic load balancing up to four Tesla Wall Connectors can share a single charging circuit. For your purpose two Tesla Wall Connectors could share a single circuit.

Change the junction box with the NEMA 14-50 receptacle to a sub panel. Install a 60A breaker at the service panel and (2) 60A breakers at the sub panel (one for each Wall Connector.) Without automatic loading balancing each Wall Connector would have to be installed on a 30A circuit, set as if it was on a 30A circuit (maximum of 24A for charging.) With automatic load balancing either of the two Wall Connectors could charge at the maximum for a 60A circuit (48A). When both Tesla vehicles are charging the maximum amperage for each Wall Connector would automatically be limited to 24A. If one Tesla vehicle completes charging sooner then the second Tesla vehicle would automatically continue, complete charging at 48A.

The Gen3 Wall Connector requires a Wi-Fi network to be able to use the automatic loading balancing capability.

The electrician will be here next Tuesday to talk about the plan. He has done many 14-50 Tesla installs but this will be his first dual wall charger set up. I'm sure if I left him alone he will do it perfectly. This post was more for me because like my wife says. "You just have to know everything"
I am going to assume that using a sub sub panel is a NO-NO. There is room to bump the 50a in the sub panel to 60a and then we have (I think 6 Ga) wire to the 14-50 box. I was hoping he could connect one wall charger to those wires and then run additional wires 15 feet to the other side of the parking spot for the other wall charger. (In series)???
Or will they really need their own 60a breaker? I THINK that can be done in the sub panel we have? He will know

 

[jcanoe]

The current 14-50 already runs off of a 100amp sub panel from our 200a main panel.

Change the existing NEMA 14-50 receptacle to a Wall Connector and change the breaker to 60A if the existing wiring will support up to 60A.. Install a second 60A circuit from the 100A sub panel to the second Wall Connector. With automatic load balancing enabled each Wall Connector will be able to charge at up to 40A when both vehicles are charging. (2X40A = 80A; the maximum allowed when charging using a 100A circuit) When only one vehicle is charging then the Wall Connector will enable charging at up to 48A.

If you skip implementing the automatic load balancing you might be able to install a 50A circuit for the second Wall Connector depending on what other circuits are on the sub panel. Each Wall Connector could charge at up to 40A, you would not be able to charge at 48A (20% more power, 20% faster charging.) Still, 40A is 25% faster than you currently charge using the Mobile Connector (32A maximum) for the Model S so maybe 40A for each Tesla would be adequate when charging both the Model S and the Model Y.

By code each EVSE needs to be on a dedicated circuit. Even with load balancing my understanding is that each Wall Connector will need to be on a separate breaker.

 

[a1machinista1]

Change the existing NEMA 14-50 receptacle to a Wall Connector and change the breaker to 60A if the existing wiring will support up to 60A.. Install a second 60A circuit from the 100A sub panel to the second Wall Connector. With automatic load balancing enabled each Wall Connector will be able to charge at up to 40A when both vehicles are charging. (2X40A = 80A; the maximum allowed when charging using a 100A circuit) When only one vehicle is charging then the Wall Connector will enable charging at up to 48A.

By code each EVSE needs to be on a dedicated circuit. Even with load balancing my understanding is that each Wall Connector will need to be on a separate breaker.

Ok the individual breakers does make sense(common). The sub panel that has the existing 14-50 wired to it also runs lights and outlets and floor heating in our downstairs father in law suite. I'm no electrician but I do not believe we have the ability (amperage) to run two 40a circuits. I'm pretty sure we are going to limited to one 60a out. Can it be done like jcanoe suggested of turning the 14-59 junction into another sub panel with two individual 60a breakers? I understand this could be code dependent.

 

[jcanoe]

I believe you may be able to change out the existing 14-50 receptacle for another sub panel. There have to be 4 wires present for the second sub panel (2-hot, 1-neutral, 1-ground.) A ground rod may be required to be driven, connected to the second sub panel. The sub panel would need to be protected against an overload with a breaker either at the current sub panel or at the new sub panel.

So the new sub panel would support 60A; each Wall Connector could enable charging at 48A (for one Tesla vehicle) or with automatic load balancing enabled each Wall Connector could enable charging at up to 24A when both vehicles were charging. Each Wall Connector would need to its own 60A breaker (assuming the wire supports up to 60A, else a 50A breaker.)

 

[a1machinista1]

I believe you may be able to change out the existing 14-50 receptacle for another sub panel. There have to be 4 wires present for the second sub panel (2-hot, 1-neutral, 1-ground.) A ground rod may be required to be driven, connected to the second sub panel. The sub panel would need to be protected against an overload with a breaker either at the current sub panel or at the new sub panel.

So the new sub panel would support 60A; each Wall Connector could enable charging at 48A (for one Tesla vehicle) or with automatic load balancing enabled each Wall Connector could enable charging at up to 24A when both vehicles were charging. Each Wall Connector would need to its own 60A breaker (assuming the wire supports up to 60A, else a 50A breaker.)

Ok, nice..... I appreciate the input. Seems any way we go it should be minimal issues if none at all.

 

[Big Earl]

Another option would be to install two Gen 2 Wall Connectors. They have non-WiFi load sharing and only require one circuit breaker for the two devices. I'm not sure how long it's going to take Tesla to implement load sharing on the gen 3 units, so gen 2 gives you an immediate load sharing option. The only caveat is they're no longer available new, so you'll have to surf the classifieds section for them.

 

[Midnightsun]

Another option would be to install two Gen 2 Wall Connectors. They have non-WiFi load sharing and only require one circuit breaker for the two devices.

Unfortunately you need a breaker for each wall connector. Thought is worked like you mentioned but no. Breakers are shown in the installation manual.

 

[Big Earl]

Unfortunately you need a breaker for each wall connector. Thought is worked like you mentioned but no. Breakers are shown in the installation manual.

My home installation definitely has both gen 2 wall connectors sharing a single 60 amp circuit breaker. It feeds a junction box in the carport where power is split to each wall connector.

This is described (including a diagram) in Appendix B on page 30 of the gen 2 wall connector installation manual found here: https://www.tesla.com/sites/default/files/downloads/wall_connector_installation_manual_80A_en_US.pdf

 

[Midnightsun]

My bad, was thinking gen 3 connectors which need breakers for each connector.