Gen3 Wall Connector Question - load sharing?

[blecchus_rex]

Then they will each have their full 60 amps per connector if there’s just one vehicle charging, but will collectively not exceed the total when multiple are plugged in.

Yes, understood - but that also works on a single circuit as well. I'm not sure I see a functional advantage (other than allowing one connector to continue functioning in some edge case scenario where the other shorts or something) to balancing over multiple branch circuits vs balancing "within" one.

There's actual disadvantage in a scenario where you've two connectors w/ say only 60A total available on a given panel/sub-panel. If you put both on a single circuit and allow the Tesla power sharing SW to manage aggregate consumption up to the max (and allow each individually to burst up to that max when there's no contention) then you've made the most of the situation. The way the manual reads (and potentially what the code stipulates) means you'd be required to provision two separate branch circuits at 30A each. In that scenario at no point could any one connector exceed the 30A though!

 

[Darblish]

Yes, understood - but that also works on a single circuit as well. I'm not sure I see a functional advantage (other than allowing one connector to continue functioning in some edge case scenario where the other shorts or something) to balancing over multiple branch circuits vs balancing "within" one.

There's actual disadvantage in a scenario where you've two connectors w/ say only 60A total available on a given panel/sub-panel. If you put both on a single circuit and allow the Tesla power sharing SW to manage aggregate consumption up to the max (and allow each individually to burst up to that max when there's no contention) then you've made the most of the situation. The way the manual reads (and potentially what the code stipulates) means you'd be required to provision two separate branch circuits at 30A each. In that scenario at no point could any one connector exceed the 30A though!

I honestly can’t remember where I read it (I’m sure on this forum somewhere), but I think there was some provision for putting in significantly larger circuits as long as the devices wired to them supported some sort of compliant load-balancing scheme. I’d bet a dollar that the manual was written either when that wasn’t a thing, or in a way that minimizes Tesla’s liability if it was allowed at the time.

Separate circuits probably limits liability, too, since it means dedicated 6awg runs from the panel to the wall connector. Overcurrent tripping the main breaker is likely preferable to overcurrent heating a wire to the point of danger.

 

[Rocky_H]

There seems to still be a lot of misunderstanding flying around on this.

And from some of the electrical code I dug up a while back (but to be clear I'm definitely not an Electrician):

210.17 Electric Vehicle Branch Circuit.


But it begs the question: what's the point of the power sharing feature then?

What you just quoted is saying for an "outlet". This is not an outlet. A wall connector is a hard-wired appliance--not an outlet. So that code section does not apply.

I also understand NEC allows a managed system load to be considered the maximum permitted by that system instead of the sum of all the branch capacities (the power sharing feature in the Tesla HPWC's ostensibly providing the managed system capability). So perhaps the only real utility of the power sharing feature is to allow over-subscription at the panel / sub-panel level... and not on individual circuits?

Yes, that is what the load sharing feature is for.

The way the manual reads (and potentially what the code stipulates) means you'd be required to provision two separate branch circuits at 30A each. In that scenario at no point could any one connector exceed the 30A though!

People seem to keep mixing this up, where they think the specification of breakers means they have to be fully completely separate circuits, but that's not true. The breakers part is about a connection method. But as the manual specifies the install, you can run one single 60A line with only 60A capable wire to a subpanel. And then from there, you can hook up four wall connectors, each with their own 60A breakers and 60A wire, and their communication (if set up properly) will stay within the 60A limit of the parent connection line. The four individual ones don't all have to be separated out to smaller sized circuits. This is what the connection sharing communication is for.

 

[blecchus_rex]

https://www.tesla.com/sites/default/files/support/charging/Gen3_WallConnector_Installation_Manual.pdf

Page 23:

Wall Connectors are allocated to individual branch circuits (each up to 60 amps).

Page 24: See both diagrams in which each connector is depicted on separate branch circuits.

I'm fully aware that (functionally) it works sharing multiple connectors on one circuit. That was the point of my post.

 

[Rocky_H]

Page 24: See both diagrams in which each connector is depicted on separate branch circuits.

I'm fully aware that (functionally) it works sharing multiple connectors on one circuit. That was the point of my post.

You had it right, where I agreed with you, about the circuit sharing, but then you had it wrong, staying that the 60A would then have to be split into two 30A circuits if they were sharing. I thought you could have just stopped and been right with your earlier explanation.

The point is that yes, they do fall into the definition of "branch circuits" because of the breakers, but not really "independent". You normally would not be able to overload 16 "independent" branch circuits that large onto one line with that small of a capacity. These are not really independent when they are communicating to regulate their current draw like this.

 

[TechnoBabble]

Im still not getting this. If two wall connectors are fed from a sub panel with 2 separate 60 amp breakers, how can it be acceptable that the breaker feeding the sub panel is 60 amps and be code compliant? Maybe in the states you have different codes.
If load sharing is enable this will work fine but if load sharing is disabled, wont both units cumulatively draw 96 amps causing the 60 amp sub panel breaker to overload?
This will never pass inspection around here.

 

[EfficientWatts]

Im still not getting this. If two wall connectors are fed from a sub panel with 2 separate 60 amp breakers, how can it be acceptable that the breaker feeding the sub panel is 60 amps and be code compliant? Maybe in the states you have different codes.
If load sharing is enable this will work fine but if load sharing is disabled, wont both units cumulatively draw 96 amps causing the 60 amp sub panel breaker to overload?
This will never pass inspection around here.

I honestly can’t remember where I read it (I’m sure on this forum somewhere), but I think there was some provision for putting in significantly larger circuits as long as the devices wired to them supported some sort of compliant load-balancing scheme. I’d bet a dollar that the manual was written either when that wasn’t a thing, or in a way that minimizes Tesla’s liability if it was allowed at the time.

Separate circuits probably limits liability, too, since it means dedicated 6awg runs from the panel to the wall connector. Overcurrent tripping the main breaker is likely preferable to overcurrent heating a wire to the point of danger.

Of course that wouldn't pass if load sharing was not enabled. But you need to look at NEC 625.42 (2020 Edition):

625.42 Rating The power transfer equipment shall have sufficient rating to supply the load served. <snip> Service and feeder shall be sized in accordance with the product ratings. Where an automatic load management system is used, the maximum equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system.

and then later on in the same section:

Sizing the service and feeder to match the adjusting means shall be permitted.

Tesla HPWC is an automatic load system if appropriately configured. Based on what I read the above, it is permitted by code to have the feeder or subpanel to be less than the sum of what could be the max output of the multiple HPWC, as long as the system was configured to respect the limit (ex. subpanel of 60A (so 48A continuous), each HPWC could have its own 60A breaker (48A continous) branch, but the communication between the HPWCs would be so that it would never exceed the rating of the feeder).

 

[a1machinista1]

Can anyone answer a question for me? We just had two Gen 3 wall connectors installed. Look, I don't want to be that guy that questions a persons work( I certainly don't like it when someone questions mine.) but considering we are over $130k for the cars and home charging. I'm gonna question it.

I am not an electrician but I will try to be short and use the correct terminology.
We have a 100a sub panel (A) that runs off of our 200a service panel. It's was to my understanding the the electrician was going to run 6Ga wire from a 60a breaker in sub panel (a) to an additional sub panel (b) in the garage.

In that sub panel (b) he was going to mount two 60a breakers, and each of those breakers would feed one of the wall connectors. And I would be able to set up the connectors to share the 60a load coming from sub panel (a).

When I got home today I was expecting to see both my wall connectors mounted with the conduit from each running to a new sub panel (b). What I found was the conduit running to
a grey box with a cover held on by four screws. I thought how will I reset the breakers if I ever needed to?

I pulled the cover off of the grey box
(sub panel b) and found that he had not installed two breakers in the box but hook both wall connectors to the same 60a feed from the first sub panel (a).

The wires are connected with (I think they are called) Polaris connectors?

Like I said, I am NOT an electrician but from what I have seen here and after reading the installation manual I think this is incorrect?

Am I correct or am I just being (that guy) and putting my nose where it shouldn't be?

 

[miimura]

Can anyone answer a question for me? We just had two Gen 3 wall connectors installed. Look, I don't want to be that guy that questions a persons work( I certainly don't like it when someone questions mine.) but considering we are over $130k for the cars and home charging. I'm gonna question it.

I am not an electrician but I will try to be short and use the correct terminology.
We have a 100a sub panel (A) that runs off of our 200a service panel. It's was to my understanding the the electrician was going to run 6Ga wire from a 60a breaker in sub panel (a) to an additional sub panel (b) in the garage.

In that sub panel (b) he was going to mount two 60a breakers, and each of those breakers would feed one of the wall connectors. And I would be able to set up the connectors to share the 60a load coming from sub panel (a).

When I got home today I was expecting to see both my wall connectors mounted with the conduit from each running to a new sub panel (b). What I found was the conduit running to
a grey box with a cover held on by four screws. I thought how will I reset the breakers if I ever needed to?

I pulled the cover off of the grey box
(sub panel b) and found that he had not installed two breakers in the box but hook both wall connectors to the same 60a feed from the first sub panel (a).

The wires are connected with (I think they are called) Polaris connectors?

Like I said, I am NOT an electrician but from what I have seen here and after reading the installation manual I think this is incorrect?

Am I correct or am I just being (that guy) and putting my nose where it shouldn't be?

That is the wiring method recommended for the Gen2 Wall Connector that uses wired comms for Load Sharing.

The manual for the Gen3 WiFi Connected Wall Connector specifies a breaker for each Wall Connector, whether wired directly from the main panel or through a sub-panel.

https://www.tesla.com/sites/default/files/support/charging/Gen3_WallConnector_Installation_Manual.pdf

The quotation for the work should have specified whether a sub panel would be used or not.

 

[kayak1]

Can anyone answer a question for me? We just had two Gen 3 wall connectors installed. Look, I don't want to be that guy that questions a persons work( I certainly don't like it when someone questions mine.) but considering we are over $130k for the cars and home charging. I'm gonna question it.

I am not an electrician but I will try to be short and use the correct terminology.
We have a 100a sub panel (A) that runs off of our 200a service panel. It's was to my understanding the the electrician was going to run 6Ga wire from a 60a breaker in sub panel (a) to an additional sub panel (b) in the garage.

In that sub panel (b) he was going to mount two 60a breakers, and each of those breakers would feed one of the wall connectors. And I would be able to set up the connectors to share the 60a load coming from sub panel (a).

When I got home today I was expecting to see both my wall connectors mounted with the conduit from each running to a new sub panel (b). What I found was the conduit running to
a grey box with a cover held on by four screws. I thought how will I reset the breakers if I ever needed to?

I pulled the cover off of the grey box
(sub panel b) and found that he had not installed two breakers in the box but hook both wall connectors to the same 60a feed from the first sub panel (a).

The wires are connected with (I think they are called) Polaris connectors?

Like I said, I am NOT an electrician but from what I have seen here and after reading the installation manual I think this is incorrect?

Am I correct or am I just being (that guy) and putting my nose where it shouldn't be?

For Gen 3 wall connectors this is not the correct setup, it's your house that may burn down you 100% need to check over the work.

As others have said you need a breaker for each. This will need to be corrected.

 

[sushih]

About a year ago, I installed two Gen 3 wall connectors. Due to my (old) house's electrical panel, they are both on the same circuit breaker circuit. I'm *eagerly* awaiting the long-promised load sharing feature so I can start using the second wall connector. Otherwise, it's basically garage wall art ;-)

Does anyone happen to know if Tesla has or will (ever!?) release load sharing support? Very frustrating at the moment... thanks!

ps: My wall connectors claim "no update available" and they are on v1.4.4. Is that the latest?

FYI- latest firmware enables power sharing… mine didn’t autoupdate, so I manually uploaded from my smartphone to the connectors. Instructions/update available Here:

Wall Connector Power Sharing | Tesla Support

With Power Sharing, you can allow up to six 3 Wall Connectors to share power and charge multiple vehicles at once. Learn how to set up and troubleshoot Power Sharing.

www.tesla.com

 

[RedEV]

I am moving into a brand new condo and have subscribed for a power supply to my two parking spaces for two Teslas. When you use two Gen 3 Wall Chargers in power sharing mode do they communicate with each other using they own wifi signals or do they need to be connected to your home wifi? I will be parking in underground parking and won't have any home wifi available.
Thanks

 

[with_raiden]

I am moving into a brand new condo and have subscribed for a power supply to my two parking spaces for two Teslas. When you use two Gen 3 Wall Chargers in power sharing mode do they communicate with each other using they own wifi signals or do they need to be connected to your home wifi? I will be parking in underground parking and won't have any home wifi available.
Thanks

Only one of the Wall Connectors will connect to your home network (the leader). The followers will connect to the leader to create the PowerSharing network.

 

[pdiamond333@gm]

No, people still continue to get this wrong. It's not every single one with a full dedicated homerun line all the way back. The way it's supposed to work (when Tesla gets around to implementing it) is still actual circuit sharing, but it's a connection method thing. They used to allow the choice of physical wire ties with things like Polaris connectors, or you could breaker each one. With the new Gen3, they just don't allow the wire splitting with Polaris connectors anymore.

You are still partially right about using a subpanel. That's basically necessary to mount the breakers. But you could do it like this: Run a 50A circuit from out of your main, 200 feet away to a parking lot or separate building, and then there, you can have the subpanel with breakers for 5 or 10 or more wall connectors. And if they are configured properly, they will make sure not to exceed that 50A (40A continuous) of the total capacity of that main circuit. See the savings? Your main wiring run out to the subpanel doesn't have to be extra thick wire to support 10X the current as if they were all separate runs to 10 wall connectors.

Sorry if this is redundant. I have a 50A breaker from my main panel going to my Gen 2 charger. I have a 2nd Tesla on the way, and removed my Gen 2 and plan to run from the 50A to sub panel with 2x 50A breakers, and then to a Gen 3 from each breaker in the sub panel. Does this sound about right.

No, people still continue to get this wrong. It's not every single one with a full dedicated homerun line all the way back. The way it's supposed to work (when Tesla gets around to implementing it) is still actual circuit sharing, but it's a connection method thing. They used to allow the choice of physical wire ties with things like Polaris connectors, or you could breaker each one. With the new Gen3, they just don't allow the wire splitting with Polaris connectors anymore.

You are still partially right about using a subpanel. That's basically necessary to mount the breakers. But you could do it like this: Run a 50A circuit from out of your main, 200 feet away to a parking lot or separate building, and then there, you can have the subpanel with breakers for 5 or 10 or more wall connectors. And if they are configured properly, they will make sure not to exceed that 50A (40A continuous) of the total capacity of that main circuit. See the savings? Your main wiring run out to the subpanel doesn't have to be extra thick wire to support 10X the current as if they were all separate runs to 10 wall connectors.

Sorry if this is redundant- Currently, I have 50A going from my main panel to my existing Gen2 Wall charger. We are adding a 2nd Tesla. I removed the Gen 2 and plan on putting in a sub panel with 2x 50A fed by the 50A in the Main and then will put a Gen 3 on each of the 50A from the sub panel. Does this sound right?

 

[miimura]

Sorry if this is redundant- Currently, I have 50A going from my main panel to my existing Gen2 Wall charger. We are adding a 2nd Tesla. I removed the Gen 2 and plan on putting in a sub panel with 2x 50A fed by the 50A in the Main and then will put a Gen 3 on each of the 50A from the sub panel. Does this sound right?

Yes, this is a valid way to change an installation from a single Wall Connector to two Load Sharing Wall Connectors.

 

[Rocky_H]

Sorry if this is redundant. I have a 50A breaker from my main panel going to my Gen 2 charger. I have a 2nd Tesla on the way, and removed my Gen 2 and plan to run from the 50A to sub panel with 2x 50A breakers, and then to a Gen 3 from each breaker in the sub panel. Does this sound about right.

Yes, I think that's right and matches what the Gen3 shows in its installation manual. You run that one 50 line, and have the sub split it into two 50 breakers, and the units will manage to keep it within that total amount.

 

[davedesa]

I have a feeling something isn't working right... I have three Gen 3 load sharing a 60amp circuit (48 amp usable) on FW 21.36.4. When two cars are plugged in and one of them is not charging the other car should pull the entire 48amps. Instead the car that's charging only pulls between 25 and 40amps. As soon as I unplug the car not charging I get the full 48 amps. Anyone run into the same issue? Thanks in advance.

 

[dailo]

I have a feeling something isn't working right... I have three Gen 3 load sharing a 60amp circuit (48 amp usable) on FW 21.36.4. When two cars are plugged in and one of them is not charging the other car should pull the entire 48amps. Instead the car that's charging only pulls between 25 and 40amps. As soon as I unplug the car not charging I get the full 48 amps. Anyone run into the same issue? Thanks in advance.

It takes a while, but it should eventually ramp up to 48. I shared my experience with it below.

Post in thread 'Gen 3 Charger Power Sharing - who has this working?'
Gen 3 Charger Power Sharing - who has this working?

 

[k.alexander]

@Rocky_H: I trust your write ups on this, can you help me quickly check my math..?
In a situation where one installs 2 Gen 3 HPWC, each HPWC can max out at 48A correct? So in order for them both to, theoretically, be able to use all 48A at the same time, one would need 96A useable, which requires what a 120A feeder circuit to a garage sub-panel that would then house two 60A breakers one for each HPWC...is that correct?

I only ask because I read somewhere that two Gen 3 HPWC can share as much as 64A, but I don't think that's true, I think they can share as much as 98A.

 

[miimura]

@Rocky_H: I trust your write ups on this, can you help me quickly check my math..?
In a situation where one installs 2 Gen 3 HPWC, each HPWC can max out at 48A correct? So in order for them both to, theoretically, be able to use all 48A at the same time, one would need 96A useable, which requires what a 120A feeder circuit to a garage sub-panel that would then house two 60A breakers one for each HPWC...is that correct?

I only ask because I read somewhere that two Gen 3 HPWC can share as much as 64A, but I don't think that's true, I think they can share as much as 98A.

If you have a 120A feeder circuit to a sub-panel with two 60A breakers, one for each Wall Connector, then you don't need load sharing at all.
Now, if you can only put a 100A breaker in your main panel because of the other loads, then load sharing will help you get the full 48A to any one car and 40A to two simultaneously.