Gen 3 Power Sharing?

[Scribby]

So, I have one Gen 3 charger, wired up to 60A in my garage; 48A max. Leaning heavily to adding another Tesla and ideally have a second charger in the garage. I've read through the gen 3 instructions, I know there are settings via wifi for power sharing, but has anyone set this up successfully? With a 60A Tesla circuit, another 50A for an outdoor hot tub, couple A/C units, I'm maxed in terms of adding another circuit. Hence, I'd like to share.

The wiring diagrams in the gen 3 manual are a bit confusing. The 60A breaker is in the main panel and the electrician pulled wire to the charger in the garage. What's the easiest way to add a second charger in this situation? Do you add a small sub panel and break from there? Would the electrician have to add any additional breakers or do the chargers handle the power distribution when both are active and charging?

In my head, I had it so they handle the work, so you just pull from the main breaker, add some sort of a sub-panel to pull two sets of wires from the same breaker, the wire to both, enable power sharing and the rest is done by the HPWCs? My head hurts.

 

[ATPMSD]

Pretty sure all you need to do is:

Add a sub-panel in the garage, add two 60-amp breakers (in the sub-panel) and run a wire to each Wall Connector from there. Then use the power sharing option to manage the load.

 

[E90alex]

You’ll need to add a sub panel then each wall connector needs its own breaker in the sub panel

 

[Scribby]

Ok, so that is easy enough. Any idea why each need a breaker in the sub panel, when there's a breaker back at the main? I was under the impression these Gen3s manage the power share and wouldn't take more than the main feed is rated at?

 

[E90alex]

That’s what Tesla says to do

 

[ATPMSD]

Although this may seem logical you cannot do that, each connector must be protected by its own breaker.

 

[ATPMSD]

If you are wondering where this comes from, NEC 210.17 states that if a circuit “…is installed for the purpose of charging an electric vehicle, then it must be a dedicated circuit.”

The circuit from the main panel to a sub-panel is considered a “feeder” circuit. Thus the rules applies for each circuit that originates from the sub-panel.

If it is not too much trouble you can upgrade the circuit from the main to the sub-panel to a 100-amp circuit. This will allow you to charge at 40-amps when both cars are on charge.

Finally, if the electrician used #6 romex, which is all too common, that wire is not rated for use at 60-amps, it is actually rated for 55-amps. According to the 80% rule the maximum continuous load allowed is 44-amps, which is less than the 48-amps the wall connector draws.

 

[holeydonut]

If you are wondering where this comes from, NEC 210.17 states that if a circuit “…is installed for the purpose of charging an electric vehicle, then it must be a dedicated circuit.”

The circuit from the main panel to a sub-panel is considered a “feeder” circuit. Thus the rules applies for each circuit that originates from the sub-panel.

If it is not too much trouble you can upgrade the circuit from the main to the sub-panel to a 100-amp circuit. This will allow you to charge at 40-amps when both cars are on charge.

Finally, if the electrician used #6 romex, which is all too common, that wire is not rated for use at 60-amps, it is actually rated for 55-amps. According to the 80% rule the maximum continuous load allowed is 44-amps, which is less than the 48-amps the wall connector draws.

How many amps can you run before you need to install a disconnect next to the EVSE?

@jjrandorin knows I disconnects.

 

[ATPMSD]

How many amps can you run before you need to install a disconnect next to the EVSE?

@jjrandorin knows I disconnects.

“Electric vehicle supply equipment rated more than 60A or more than 150V to ground…”

The Wall Connector is 60-amps (max) and each hot is 120v to ground; a disconnect is not needed.

 

[Rocky_H]

Any idea why each need a breaker in the sub panel, when there's a breaker back at the main? I was under the impression these Gen3s manage the power share and wouldn't take more than the main feed is rated at?

Yes, and you can see the reason why in the difference of how the Gen2 wall connectors versus the Gen3 wall connectors handle their sharing.

On the Gen2 wall connectors, you had one primary one that controlled everything. You set that one with the amp level of the whole system. You picked only ONE amp level. Then all of the others were just set to the "slave" setting. So all of them had to be installed to the specification of that full amp level, with that proper gauge of wire. So in that installation setup, you could just tie the power wires together without extra breakers since they all had to be installed at the same amp level.

In the Gen3 setup, you can have every one configured for a distinct amp level if you want. So you can have a 20A, a 30A, a 40A, and a 60A, with each one having different sized wire, and then each needs to be set to a breaker that is for that amp level. But they also communicate to keep the total within the limit of the main feeder line capacity.

 

[branland]

I cannot get the power sharing to work. I’ve got two gen 3 wall chargers on separate 60 amp breakers in my main box. The disable power sharing button is under intensified and cannot be selected. Zero devices show up on the network and when you try to add them to the network the app says they’ve already on the network.

I’ve cycled the wall chargers several times. Connected them to a different router, used a different browser, nothing works.

Anyone else have this problem?

 

[branland]

Didn't read all the posts. Why do I need to add a subpanel? I have 200 amp service, but when both cars hit, the load analysis is a bit sketchy. Right now the Model Y starts at midnight and the S is set to be ready to go by 6 so they don't overlap.

 

[ATPMSD]

I cannot get the power sharing to work. I’ve got two gen 3 wall chargers on separate 60 amp breakers in my main box. The disable power sharing button is under intensified and cannot be selected. Zero devices show up on the network and when you try to add them to the network the app says they’ve already on the network.

I’ve cycled the wall chargers several times. Connected them to a different router, used a different browser, nothing works.

Anyone else have this problem?

Pretty sure the WCs need to be able to see each other, so if they are in separate locations this could be a problem. If you have not read this document it may help:

https://www.tesla.com/support/charging/wall-connector/power-sharing#:~:text=The%20minimum%20current%20limit%20is,network%20limit%20of%20287%20amps.

If this fails, I would log onto each WC and do a reset, then start again.

 

[branland]

Will give it a try.

 

[branland]

Still not working. Is there a trick to doing the reset? Can't find it in any of the menus.

 

[branland]

Just in case anyone else is having this problem. I was doing some research and found out your supposed to be able to access the wall connectors directly from the tesla App. First thing it tried to was update the firmware. One of the chargers updated to 23.24.8, the other kept failing. Cycled them both off an on at the breaker. Will try again tomorrow.

 

[ATPMSD]

Still not working. Is there a trick to doing the reset? Can't find it in any of the menus.

Well, there used to be a menu item to reset but it looks like it has been removed. May I suggest you contact Tesla at:

[email protected]

 

[branland]

Persistence. Got it working. Upgraded to firmware 23.24.3 through the Tesla app. Downloaded the Tesla Pro app and it allowed me to access power sharing.

 

[rstx]

The Tesla Universal Wall Connector manual shows a diagram of having multiple wall connectors on a 60A circuit. They also show a design with them each on their own dedicated circuit(s). The power sharing feature of the Wall Connectors shares the available 48A between the wall connectors. If there is only one vehicle drawing a charge it can utilize the full 48 amps. If there are two charging it shares up to 48 amps between the two chargers. There is a YT video of someone plugging in two different wall connectors and they load balance the available power between two vehicles while charging. If you have two dedicated 60A breakers you most likely dont need to use the features of power sharing at all. You *could though set a max draw when both are in use if there is an overall headroom issue at the load center panel.

 

[davewill]

The Tesla Universal Wall Connector manual shows a diagram of having multiple wall connectors on a 60A circuit. They also show a design with them each on their own dedicated circuit(s). The power sharing feature of the Wall Connectors shares the available 48A between the wall connectors. If there is only one vehicle drawing a charge it can utilize the full 48 amps. If there are two charging it shares up to 48 amps between the two chargers. There is a YT video of someone plugging in two different wall connectors and they load balance the available power between two vehicles while charging. If you have two dedicated 60A breakers you most likely dont need to use the features of power sharing at all. You *could though set a max draw when both are in use if there is an overall headroom issue at the load center panel.


View attachment 981275

View attachment 981281

That would appear to be a Gen2 manual page. The Gen3 manual no longer shows (or allows) multiple wall connectors on a single circuit breaker. They expect each WC to have it's own breaker.