Adding a 2nd Tesla home charger and tapping the wires.

[That Beast Mode]

I have a question about adding a second charger that maybe some of you might know the answer to for me - and before you jump on me, I am not planning on doing this myself, I'll have a licensed electrician confirm and do the work, I just don't want to sound stupid when I am discussing what I want with them.

I have Romex wire in my garage on a 50A breaker currently for my Tesla wall charger. I want to install a second wall charger outside the garage. Can the electrician tap off the existing wires to run a line for the second charger? I want to be able to plug both cars in at the same time - I don't think they would be able to both charge at the same time and that's fine with me.

If this is possible, do the Tesla chargers handle which one gets charged? Does it half and split the power and charge both with this method? I don't want to overload the wires obviously. The install is way easier than getting another run installed from the breaker in the basement to the garage. I know the better way is to have dedicated lines to the panel for both chargers so they can run at full capacity when needed, but I never have a circumstance where I need to charge both at the same time. It's always one or the other but I'd like to not keep having play musical chargers and just add a second one. Thanks.

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[fishtek]

@Gigahorse , I'm not sure that is exactly true. If installed and setup properly (group mode), then I believe it can balance the power in a smart way to not trip the breaker.

I believe that is what is described here:
https://www.tesla.com/support/charging/wall-connector/power-management

 

[eswimm]

Tesla Wall Connectors have been able to share wiring since at least gen 2, not sure about gen 1. As long as they're configured properly, they'll never draw more than the allowable current between the shared wiring. For a 50A circuit, that's 40A split between the chargers.

 

[That Beast Mode]

@Gigahorse , I'm not sure that is exactly true. If installed and setup properly (group mode), then I believe it can balance the power in a smart way to not trip the breaker.

I believe that is what is described here:
https://www.tesla.com/support/charging/wall-connector/power-management

This was my understanding as well and why I asked the question. Balancing the power is perfectly fine for my use case, burning down my house is not.

 

[That Beast Mode]

Tesla Wall Connectors have been able to share wiring since at least gen 2, not sure about gen 1. As long as they're configured properly, they'll never draw more than the allowable current between the shared wiring. For a 50A circuit, that's 40A split between the chargers.

I have the newest version of the charger I believe, Gen 3 maybe? So the electrician should be able to configure it this way right? Now does it share the power and split it (20A each) if both need to charge let's say? or will it fully charge one then go to the other? Like I said, I don't really need both to charge at the same time, I'm just curious. I currently have it on the 50A and charging at 40A but I'm only able to plug in one at a time.

 

[pricedm]

..I have Romex wire in my garage on a 50A breaker currently for my Tesla wall charger.

Is your Tesla wall charger gen 2 or gen 3?

With Gen 2 this easy to do. Run both on one circuit. One HPWC is the "leader" and all others downstream are "followers." Configure the DIP switches for Leader and Follower, and set max current. A communication wire links the charges.

For Gen 3...I don't have the manual in front of me....go to Tesla for details.

 

[mongo]

I have a question about adding a second charger that maybe some of you might know the answer to for me - and before you jump on me, I am not planning on doing this myself, I'll have a licensed electrician confirm and do the work, I just don't want to sound stupid when I am discussing what I want with them.

I have Romex wire in my garage on a 50A breaker currently for my Tesla wall charger. I want to install a second wall charger outside the garage. Can the electrician tap off the existing wires to run a line for the second charger? I want to be able to plug both cars in at the same time - I don't think they would be able to both charge at the same time and that's fine with me.

If this is possible, do the Tesla chargers handle which one gets charged? Does it half and split the power and charge both with this method? I don't want to overload the wires obviously. The install is way easier than getting another run installed from the breaker in the basement to the garage. I know the better way is to have dedicated lines to the panel for both chargers so they can run at full capacity when needed, but I never have a circumstance where I need to charge both at the same time. It's always one or the other but I'd like to not keep having play musical chargers and just add a second one. Thanks.

Group power management will limit draw to 40A combined.
UWC has feed through lugs.

 

[eswimm]

I have the newest version of the charger I believe, Gen 3 maybe? So the electrician should be able to configure it this way right? Now does it share the power and split it (20A each) if both need to charge let's say? or will it fully charge one then go to the other? Like I said, I don't really need both to charge at the same time, I'm just curious. I currently have it on the 50A and charging at 40A but I'm only able to plug in one at a time.

Gen 2 was different, but watching the video on Gen 3/UWC it sounds like they share the circuit evenly, so 20A per vehicle until one is done, then the other gets the full 40A.

 

[That Beast Mode]

Is your Tesla wall charger gen 2 or gen 3?

With Gen 2 this easy to do. Run both on one circuit. One HPWC is the "leader" and all others downstream are "followers." Configure the DIP switches for Leader and Follower, and set max current. A communication wire links the charges.

For Gen 3...I don't have the manual in front of me....go to Tesla for details.

I believe it is a Gen 3, I got it when I got my CT, so it's less than a year old, but I'd have to confirm to be absolutely sure. Do I need to add the communication wire or is that something built in?

 

[That Beast Mode]

Gen 2 was different, but watching the video on Gen 3/UWC it sounds like they share the circuit evenly, so 20A per vehicle until one is done, then the other gets the full 40A.

This would be perfect for what I'm looking to do. So I shouldn't need any other special equipment other than having the electrician do the wiring and buying a second wall charger. Thanks

 

[pricedm]

I believe it is a Gen 3, I got it when I got my CT, so it's less than a year old, but I'd have to confirm to be absolutely sure. Do I need to add the communication wire or is that something built in?

Yours is a Gen 3. Communication from leader to follower is over WiFi.

Each HPWC is on its own circuit. See “Group Power Management Overview”

https://www.tesla.com/support/charging/wall-connector/power-management

 

[devdrone6]

I have a question about adding a second charger that maybe some of you might know the answer to for me - and before you jump on me, I am not planning on doing this myself, I'll have a licensed electrician confirm and do the work, I just don't want to sound stupid when I am discussing what I want with them.

I have Romex wire in my garage on a 50A breaker currently for my Tesla wall charger. I want to install a second wall charger outside the garage. Can the electrician tap off the existing wires to run a line for the second charger? I want to be able to plug both cars in at the same time - I don't think they would be able to both charge at the same time and that's fine with me.

If this is possible, do the Tesla chargers handle which one gets charged? Does it half and split the power and charge both with this method? I don't want to overload the wires obviously. The install is way easier than getting another run installed from the breaker in the basement to the garage. I know the better way is to have dedicated lines to the panel for both chargers so they can run at full capacity when needed, but I never have a circumstance where I need to charge both at the same time. It's always one or the other but I'd like to not keep having play musical chargers and just add a second one. Thanks.

I have the lectron splitter - it has been working fine for me, might work for you. I just added pigtails to the tesla charger and plugged it in.

Lectron

 

[smcnaughton829]

Sub panel, then get 2 50 amp breakers install in your garage. Run new line to your original charger and a new line to your new charger.
Set up load share on the master charger. Add the slave charger. All done in the Tesla one app.
NOTE: UWC setup on the Tesla power share to back up your house DOES NOT allow load share.
I have 2 WC setup for load share and 1 UWC for power share. 2 different circuits, UWC all by its self, load share split from sub panel.
easy pezzy lemon squeezy

 

[mongo]

Yours is a Gen 3. Communication from leader to follower is over WiFi.

Each HPWC is on its own circuit. See “Group Power Management Overview”

https://www.tesla.com/support/charging/wall-connector/power-management

Or on one circuit with UWC first.

https://digitalassets.tesla.com/tes...-Wall-Connector-Installation-Manual-NA-EN.pdf

 

[CT_AZ_4x4]

Yours is a Gen 3. Communication from leader to follower is over WiFi.

Each HPWC is on its own circuit. See “Group Power Management Overview”

https://www.tesla.com/support/charging/wall-connector/power-management

I can confirm the accuracy of Mongo’s post. (I have never seen him post anything but accurate info.)

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