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

[mongo]

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

Look more closelyer

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[pricedm]

Look more closelyer

Good ol' Tesla....removing redundant parts and simplifying. Lots of flexibility with the Gen 3 chargers, as shown in your post #15. Lots of good info in the install manual.

 

[That Beast Mode]

Thanks for the heads up guys, appreciate it. So I had a licensed electrician come down today, I wasn't home but my wife told me what he said (am I crazy?). He suggested either running a new line from the panel to where I want the charger - which is fine, but not really what I was looking to do if avoidable. Or if I wanted to tap off the existing one, he suggested running it off of a 90A breaker - correct me if I'm wrong here, but it sounds like I need a new electrician first before a new charger. Am I missing something or is this guy trying to burn my house down? That sounds completely wrong and unsafe to me, but I'm not a licensed electrician.

 

[That Beast Mode]

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

Is there a benefit to running the sub-panel with 2x 50A breakers vs just tapping off the existing line to add the new charger? The existing line is already on a 50A breaker, wouldn't that just make it 3x 50A breakers vs the one?

 

[That Beast Mode]

Or on one circuit with UWC first.

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

This seems like the way to go and what I was looking to accomplish.

 

[devdrone6]

This seems like the way to go and what I was looking to accomplish.

If the electrician is willing to take the time to understand this, it is the right way to go. I suggested the splitter way if you don’t mind charging one at a time and more importantly, want to do it yourself the easy way.

I don’t think your electrician understood what you want.

 

[smcnaughton829]

Is there a benefit to running the sub-panel with 2x 50A breakers vs just tapping off the existing line to add the new charger? The existing line is already on a 50A breaker, wouldn't that just make it 3x 50A breakers vs the one?

No daisy chain. And running the breaker this way would help eliminate the worry about burning down the house. Just think of the only 1 breaker you have on the system is bad, well there goes your house

 

[That Beast Mode]

No daisy chain. And running the breaker this way would help eliminate the worry about burning down the house. Just think of the only 1 breaker you have on the system is bad, well there goes your house

Fair enough, I guess if redundancy is good enough for Tesla then it's good enough for me. It makes sense tho

 

[That Beast Mode]

If the electrician is willing to take the time to understand this, it is the right way to go. I suggested the splitter way if you don’t mind charging one at a time and more importantly, want to do it yourself the easy way.

I don’t think your electrician understood what you want.

I don't have an outlet in the garage for 240, my current charger is hard wired.

 

[HaulingAss]

I don't have an outlet in the garage for 240, my current charger is hard wired.

Good job! Hardwiring is the way to go, outlets are for people who don't understand the tradeoffs. Even if you have an existing outlet, it's almost always better to simply remove the outlet and use the same wires to hardwire a Wall Connector. One less point of resistance, one less point of failure.

Regardless of what the media is saying about EVs, the country is going to continue to migrate to EVs. Most single family homes will need EV charging in the next several years, and almost all of them will need NACS connectors, so it's an investment into your home when the time comes to sell it.

 

[mongo]

No daisy chain. And running the breaker this way would help eliminate the worry about burning down the house. Just think of the only 1 breaker you have on the system is bad, well there goes your house

Counterpoint:
1: the sub-panel is as much daisy chain as using the UWC lugs
1a: the UWC has internal temperature sense, the sub panel does not
2: none of the loads in the house are double breakered
2a: technically, 240V breakers (in NA) are two breakers, as long as they haven't latched mechanically. As long as it it's a load fault, not a short to ground, there is redundancy.

 

[That Beast Mode]

Counterpoint:
1: the sub-panel is as much daisy chain as using the UWC lugs
1a: the UWC has internal temperature sense, the sub panel does not
2: none of the loads in the house are double breakered
2a: technically, 240V breakers (in NA) are two breakers, as long as they haven't latched mechanically. As long as it it's a load fault, not a short to ground, there is redundancy.

So you're saying the daisy chain is a better option than the sub-panel? Also, when you say UWC lugs, you're referring to the screw down connections inside the charger right? All the points seem valid, but I don't know that's why Im asking questions. Any comments on what the electrician told me? I figured they would know for sure, but I did not agree with what he told me at all - maybe I'm wrong tho

 

[CyberGus]

Or if I wanted to tap off the existing one, he suggested running it off of a 90A breaker

This makes no sense.

Obviously he doesn’t understand that the UWCs are smart, and can limit their collective current.

Regardless, you can’t magically turn a 50A circuit into a 90A circuit by swapping the breaker. If you pull 90A through 6AWG then the melting wire becomes the breaker lol.

 

[CyberGus]

So you're saying the daisy chain is a better option than the sub-panel? Also, when you say UWC lugs, you're referring to the screw down connections inside the charger right?

The UWC is designed to be safely daisy-chained, using Group Management to ensure the circuit capacity is never exceeded.

But can you link UWCs when using PowerShare?
Asking for a friend

 

[mongo]

So you're saying the daisy chain is a better option than the sub-panel? Also, when you say UWC lugs, you're referring to the screw down connections inside the charger right? All the points seem valid, but I don't know that's why Im asking questions. Any comments on what the electrician told me? I figured they would know for sure, but I did not agree with what he told me at all - maybe I'm wrong tho

I'm saying subpanel doesn't bring much, if anything, to the party and doesn't give you the minimal tear up install you are looking for.
I reference UWC because it is the only Tesla WC with two sets of lugs to allow for daisy chaining. I think it can group power share with a Gen 3, so you might need to swap the existing one for the UWC, but then you use the one you have at the new location.
90A makes no sense to me unless they meant a new 90A circuit from the main panel to the new subpanel. With my Powershare install, I had a 100A feed run to a subpanel in the detached garage, but it only had a 15A 120V feed originally.

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