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HPWC Gen 2 & Gen 3 Load Balancing

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I had a Gen 2 for my Model 3 and bought a Gen 3 for my new Model S but my electrician told me they couldn't load balance. He said I either needed 2 Gen 2's which communicate via a wire or 2 Gen 3's which communicate over WiFi. Not having backwards compatibility on the Gen 3 seems like an unimaginable oversight. Does anyone know of a way to get them to load balance so I don't have to plug the cars in on alternate days?

Peter
 
I had a Gen 2 for my Model 3 and bought a Gen 3 for my new Model S but my electrician told me they couldn't load balance. He said I either needed 2 Gen 2's which communicate via a wire or 2 Gen 3's which communicate over WiFi. Not having backwards compatibility on the Gen 3 seems like an unimaginable oversight. Does anyone know of a way to get them to load balance so I don't have to plug the cars in on alternate days?

Peter
Oh, I asked Tesla charging support about this twice in the past 10 days via email and have yet to receive a reply.
 
They are not compatible. Two gen 2s can run off the same circuit where as 2 gen 3 require individual dedicated circuits.

So you might a as well run separate circuits to run both at the same time as you would have had to with two gen 3s anyway. The gen 3 power sharing feature (not enabled yet and will require a software upgrade) allows you to not have to upgrade the service at your house as you can specify how much the two of the will pull at any one time. With both a gen 2 and a gen 3, you will have to make sure the home electrical service would not be overrun by potentially 96 amps (but I’m assuming it currently supports 80 amps since you were going to daisy chain...so just set them both to 40a max and you will have no issue).

It’s not as much an over-site as it is the hardware and wire gauge necessary to support load sharing. To have backwards compatibility would have really bulked up the gen 3 and I’m glad they chose to leave it out. Technology will move on (this from gen 2 owner) but it doesn’t sound like it will affect you too much.
 
They are not compatible. Two gen 2s can run off the same circuit where as 2 gen 3 require individual dedicated circuits.

So you might a as well run separate circuits to run both at the same time as you would have had to with two gen 3s anyway. The gen 3 power sharing feature (not enabled yet and will require a software upgrade) allows you to not have to upgrade the service at your house as you can specify how much the two of the will pull at any one time. With both a gen 2 and a gen 3, you will have to make sure the home electrical service would not be overrun by potentially 96 amps (but I’m assuming it currently supports 80 amps since you were going to daisy chain...so just set them both to 40a max and you will have no issue).

It’s not as much an over-site as it is the hardware and wire gauge necessary to support load sharing. To have backwards compatibility would have really bulked up the gen 3 and I’m glad they chose to leave it out. Technology will move on (this from gen 2 owner) but it doesn’t sound like it will affect you too much.
I have a 60 amp circuit and no more room on my panel for a dedicated run. :-/ Maybe I can look into setting them both to 30 amps.
 
Seems unfair to have to buy another Gen 2 to make it work right now or another Gen 3 to make it work right on an unknown future date plus having to pay the Electrician again. It seems I have to either charge one at 12 amps and one at 48 amps which seems ridiculous or throw something I just paid for in the trash and pay another $1k.
 
They are not compatible.
Yes, that part is true.
Two gen 2s can run off the same circuit where as 2 gen 3 require individual dedicated circuits.
No, that is not true, but I keep seeing people state this over and over and over here in this forum. The gen 3 do not require individual dedicated circuits. Dedicated seems to be indicating a straight run all the way back to the main panel, and they don't require that.

You can run one dedicated circuit to a subpanel, and then you can hook up 10 or 12 or 15+ gen3 wall connectors from that one circuit whenever they do actually get that power sharing software update completed. What is getting people confused with this is that it says you can't do the direct wire splicing like with Polaris connectors like you could with the gen2. The gen3 does require using a subpanel with individual breakers to split up the single circuit supply that is being shared.

Houses sometimes do subpanels for regular wiring stuff, but code has specifications of how much capacity of subcircuits you can put in so you don't oversubscribe the supply that runs into the subpanel. But that's what is different about these gen3 wall connectors. They aren't considered separate circuits, so they don't have to be limited by that constraint.
 
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Gen 3 do require a dedicated circuit. I follow your logic about sub panels but it is not complete and incorrect to state it that way. A circuit in electrical design goes from a panel (main or sub) to a load device. Gen3 require individual circuit breakers and individual runs back to a panel (main or sub). Gen 2s can appear as one load on a single circuit breaker. Yes, technically the combination of the sub panel and G3’s can be considered a single load in the main panel, but from the gen 3 perspective, they need individual circuits:

From Tesla’s gen3 manual:
“Wall Connectors are allocated to individual branch circuits”
Page 25 of https://www.tesla.com/sites/default...ng/Gen3_WallConnector_Installation_Manual.pdf

The keyword here is individual circuits. Also look at the next page where each gen 3, whether it has a sub panel or not, has dedicated 60a breakers and a dedicated run from that breaker.
 
Gen 3 do require a dedicated circuit. I follow your logic about sub panels but it is not complete and incorrect to state it that way. A circuit in electrical design goes from a panel (main or sub) to a load device. Gen3 require individual circuit breakers and individual runs back to a panel (main or sub). Gen 2s can appear as one load on a single circuit breaker. Yes, technically the combination of the sub panel and G3’s can be considered a single load in the main panel, but from the gen 3 perspective, they need individual circuits:

From Tesla’s gen3 manual:
“Wall Connectors are allocated to individual branch circuits”
Page 25 of https://www.tesla.com/sites/default...ng/Gen3_WallConnector_Installation_Manual.pdf

The keyword here is individual circuits. Also look at the next page where each gen 3, whether it has a sub panel or not, has dedicated 60a breakers and a dedicated run from that breaker.
You say the keyword here is "individual circuits", but that obviously would not work with NEC if you considered them literally like that. You could have a 60A supply to a sub and then 16 breakers for a total of 960 amps worth of circuits in there. That would never fly by code if they were considered separate circuits with separate appliances. They only way that is allowed is precisely because they are not separate circuits.
 
that obviously would not work with NEC if you considered them literally like that
Of course! But you are assuming the sub-panel is just for G3 chargers and if you do that, you would be right. But many times sub-panels handle loads other than exclusively EVs. That's just electrical design with regards to standard capacity planning. That applies to a main panel or a sub-panel.

To be clear, a G3 HPWC requires a dedicated "run" to a panel (main or sub) with a dedicated breaker. Call the "run" what you will. Tesla calls it a branch circuit.
 
Of course! But you are assuming the sub-panel is just for G3 chargers and if you do that, you would be right. But many times sub-panels handle loads other than exclusively EVs. That's just electrical design with regards to standard capacity planning. That applies to a main panel or a sub-panel.

To be clear, a G3 HPWC requires a dedicated "run" to a panel (main or sub) with a dedicated breaker. Call the "run" what you will. Tesla calls it a branch circuit.
I suppose we are referring to different aspects of it. Physically, as you are referring to, yes, the connections are made to look the same way as if they were normal separate branch circuits.

But for the application of calculated loads, they are not used as separate circuits. The section 625.41, which was added in the 2017 NEC updates specifically deals with these load management systems in EVSEs, and it says to treat the collection of all of them that are communicating as one load, not as separate. Here are a couple of examples/explanations:

Load Sharing Use and Setup

Power Management FAQ | ChargePoint
 
My HPWC 2 and HPWC 3 were both installed (at separate times) on the same circuit of a sub panel on a double throw breaker listed as 60 on each throw. The electrician did not tell me that the 2 wall chargers would not be able to load balance so when both of my cars tried to charge at the same time for the first time, I was quite surprised that the breaker tripped and when I went to reset it, it was so hot that it burned my finger.

After bringing this to my electricians attention, he said that the two chargers cannot be used together since they could not load balance because they don't communicate the same way. He told me that I could buy another HPWC 2 and he could have them load balance via a communications wire OR I could buy another HPWC 3 and have it installed so the two v3's could communicate via WiFi at an unknown time in the future. What if Wifi goes out when they need to begin a load balanced charging session? dunno.

I never assumed any of this would be an issue and just bought what Tesla sold me. Now I'm in an awkward and expensive jam.

Peter
 
Yeah. It’s a bad situation. Did someone actually tell you it would be supported before you bought it? If it was Tesla I would call them and let them know your situation and what they told you. Most purchasers are not electricians and would not be the type to read the manual.

I would be upset at the electrician not letting you know when he/she wired up the new 3G. Surely they read the install manual? It’s pretty clear in there.
 
My HPWC 2 and HPWC 3 were both installed (at separate times) on the same circuit of a sub panel on a double throw breaker listed as 60 on each throw. The electrician did not tell me that the 2 wall chargers would not be able to load balance so when both of my cars tried to charge at the same time for the first time, I was quite surprised that the breaker tripped and when I went to reset it, it was so hot that it burned my finger.
Huh--that's weird that he would install them that way then, since they can't load balance to share a circuit.
After bringing this to my electricians attention, he said that the two chargers cannot be used together since they could not load balance because they don't communicate the same way. He told me that I could buy another HPWC 2 and he could have them load balance via a communications wire OR I could buy another HPWC 3 and have it installed so the two v3's could communicate via WiFi at an unknown time in the future. What if Wifi goes out when they need to begin a load balanced charging session? dunno.
They don't manage that through your home wi-fi internet connection. The units provide their own hotspot of their own mesh network. So they are all supposed to be communicating directly with each other, not through your home router. And I think if their communication fails, they will default to some much lower level while reporting an error. Still not implemented, anyway, to be sure though.

I never assumed any of this would be an issue and just bought what Tesla sold me. Now I'm in an awkward and expensive jam.
When the gen3 first became available, people asked Tesla if there would be backward compatibility for that, and they said no, and they never plan to either. It's an inconvenient situation and not ideal, but doesn't have to be expensive. You can just put them on separate breakers and run them as two separate 30A circuits. Or a 40A and a 20A if one of the cars normally does less miles. I know it's not what you wanted, but that is a cheap and easy solution to use both.
 
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I spoke with the same Tesla advisor that I set my Model 3 purchase up with in late 2019. I placed an order for a 2020 Model S Performance and after I did, he emailed me and said to make sure I get an extra wall charger which I did. Unbeknownst to me, the day I bought it was the first day the HPWC 3 hit their website. I didn't know I was buying anything different to what I bought before.

I was upset when the installer had to spend 30 minutes on the phone with his boss because he'd never seen a v3 before. When he finished the install, he gave me no special instructions. The electrician later told me that if they did anything wrong, they'd stand by their work. Since both chargers work, they don't feel like they did anything wrong. The fact that they can't load balance is an issue beyond their control as far as they are concerned.
 
The fact that they can't load balance is an issue beyond their control as far as they are concerned.
This is your main issue. If they installed it like that without reading the obvious instructions, with the possibility over overload on a 240V circuit I would think is against code. The fact that it burned your hand is not just a human hazard, but a REAL fire hazard. I don't think Tesla has done anything wrong here, but surely your electrician has. They are the ones who "assumed" it would work, and since they are the professionals and paid to RTFM, they are at fault, at least IMHO. At the very least, they should come out and re-wire the G3 charger to it's own breaker so you don't overload that 60A breaker, causing it to heat to potentially the point of fire. If you have the spare capacity in your main panel, there should be no issue.

In the end, the electrician should have quoted you either:
1. a dedicated run from the G3 charger to your panel (mimicking your G2 charger)
2. install a sub-panel between the main panel and your G2 charger, allowing you to branch to both the G2 and G3 chargers.
3. return the G3 and search online for a G2 charger (you see them all the time for sale on this community).

1 and 2 likely would cost more than your initial quote in both hardware and man-hours so if they end up going that route, I do think you should be on the hook for the difference. However, since they put your house in an obviously unsafe, and potentially against code situation, perhaps they can knock something off the labor rate. I would be very nice with them but if they get to a point where they are being unreasonable, politely mention you might want to ask your local authority to "safety check" the installation. Be careful here as I don't know all the local regulations and if you/they were supposed to pull a permit first.
 
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This is your main issue. If they installed it like that without reading the obvious instructions, with the possibility over overload on a 240V circuit I would think is against code. [...] and potentially against code situation
You're being generous with this. There's no question. That is definitely against code. In the 2017 updates, they made this iron-clad. An EVSE must be on its own circuit unless it is part of a load sharing setup, and since that is not set up here, having them share a breaker is not allowed.
 
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So can the 60amp double throw breaker be swapped out for 2 30 amp breakers so each charger can run on their own circuits at 30amps? I have no extra space on the sub panel. Either that or I can set my wife's v2 to 20 amps and my v3 to 40 amps?
Yeah, if you already have 60A allocated, you can always split that up however you want. When you say no extra space in the subpanel, that would be a pretty small bit of work to replace that with a slightly bigger subpanel with more slots.

Or if you have a few regular 120V circuits, you might be able to switch some of those to "twin" breakers that fit two in the space of one. They look like this, for example:
Siemens 20 Amp Tandem Single Pole Type QT Circuit Breaker-Q2020U - The Home Depot

Or you could go the other way, with two 240V circuits, they make what are called "quad" breakers, where they fit two two-pole breakers into a double space. Basically they link the interior two switches as one and the outer switches as the other. That could let you do the two 30A or a 40A and 20A. Here's an example of a double 30A one like that.
Eaton BR 2-30 Amp 2 Pole BQ (Independent Trip) Quad Circuit Breaker-BQ230230 - The Home Depot

You do need to make sure with an electrician about what will fit, because not all panels are made to take twin or quads and you usually can't mix and match brands of the breakers versus panels.