Planning for 2nd HPWC & load sharing. Have Gen 2. Questions.

[destructure00]

I currently have a 24' Gen 2 HPWC installed on a 60 amp breaker to charge my Model 3 at 48 amps. Starting to plan to get my wife a Model Y. I don't have capacity in my panel to run a second HPWC at full rate, so needing to do a load sharing setup. I'm going to end up having to make a choice between trying to find a second Gen 2 on the resale market (hopefully without getting gouged on price), or selling my Gen 2 and buying two Gen 3s.

I understand the "how" of load sharing between Gen 2 and 3, wired vs wireless, and that Gen 3 load sharing hasn't actually been released yet.

My question is regarding wiring. I see that each Gen 3 requires it's own branch circuit and a dedicated breaker. So in my case, even though I plan to share 48 amps total, each unit would be on it's own dedicated 60 amp breaker. Unless I'm misunderstanding, that's pretty straightforward.

Can I run two Gen 2s in the same configuration? The manual shows one branch circuit with a single breaker (60 amp in my case) running to a junction box, then each HPWC wired into the junction box. Because of the proximity to my main panel, I'd prefer to have two separate branch circuits rather than having to install a junction box. I guess I'm just not understanding why Gen 2 would require a single breaker/circuit with junction box where Gen 3 requires separate breakers/circuits. Both setups are load sharing, it's just the communication method between them that's different. Am I missing something here?

 

[araxara]

Can I run two Gen 2s in the same configuration? The manual shows one branch circuit with a single breaker (60 amp in my case) running to a junction box, then each HPWC wired into the junction box. Because of the proximity to my main panel, I'd prefer to have two separate branch circuits rather than having to install a junction box. I guess I'm just not understanding why Gen 2 would require a single breaker/circuit with junction box where Gen 3 requires separate breakers/circuits. Both setups are load sharing, it's just the communication method between them that's different. Am o missing something here?

You can run a Gen-2 either way. In my setup, I have 3 Gen-2 HPWCs on 3 separate 100A breakers.

 

[destructure00]

You can run a Gen-2 either way. In my setup, I have 3 Gen-2 HPWCs on 3 separate 100A breakers.

That's what I was hoping to hear. Yours load share, right?

 

[boaterva]

Who says each Gen 3 ‘needs’ a separate breaker? That’s what it strictly has written down but how is that ‘required? It has no way of knowing what it’s connected to. We had this conversation when they came out and there is no way for a device to test for breaker capacity.

I have two Gen 2’s on a 100 amp circuit (load sharing) and they are set to max (80 amps). If I ever need to replace them with two Gen 3’s, they are getting set to max, of course. No issue here, because the 3’s are lower capacity but those with lower single shared circuit capacity can still use it on two Gen 3’s.

The single circuit for each is a good idea because you can then shut down one separately for repair. If you are starting from scratch, still recommended for that reason. But not to redo already installed wiring.

 

[boaterva]

Of course you can run Gen 2 on separate circuits, the point of the original idea was not to require 200 amps for 100 shared. Most houses have 200 total for the entire house. 100 each for two HPWCs was the point of load sharing since normally both cars aren’t charging full speed at the same time. And now of course few/none have chargers over 40 amps anyway.

 

[boaterva]

Who says each Gen 3 ‘needs’ a separate breaker? That’s what it strictly has written down but how is that ‘required? It has no way of knowing what it’s connected to. We had this conversation when they came out and there is no way for a device to test for breaker capacity.

I have two Gen 2’s on a 100 amp circuit (load sharing) and they are set to max (80 amps). If I ever need to replace them with two Gen 3’s, they are getting set to max, of course. No issue here, because the 3’s are lower capacity but those with lower single shared circuit capacity can still use it on two Gen 3’s.

The single circuit for each is a good idea because you can then shut down one separately for repair. If you are starting from scratch, still recommended for that reason. But not to redo already installed wiring.

Love people who disagree and don’t say about what exactly. What’s the actual issue?

 

[destructure00]

Love people who disagree and don’t say about what exactly. What’s the actual issue?

Not sure what that's all about, but I appreciate the input and I am now planning on wiring in a second branch circuit for the second HPWC. This gives the most flexibility, as I have the choice of either getting a second Gen 2 and pulling a twisted pair or selling my current Gen 2 and buying two Gen 3s.

 

[Rocky_H]

Love people who disagree and don’t say about what exactly. What’s the actual issue?

Well, it wasn't me, but I was considering it. It's probably because of this:

Who says each Gen 3 ‘needs’ a separate breaker?

The instruction/installation manual, which means it's the manufacturer of the device who is saying it.

That’s what it strictly has written down...

Yes. Yes it is.

but how is that ‘required? It has no way of knowing what it’s connected to. We had this conversation when they came out and there is no way for a device to test for breaker capacity.

It is a slightly different kind of system, so the performance and fallback conditions can be a little different. They allow up to 16 devices on one circuit for the new one, and they can be allocated for different amounts of amps on each one, so they are trying to keep it straightforward that you breaker each one for how much it's going to get. The old one let you do wire-to-wire Polaris connectors, but all of the wiring had to be matched to the full spec of the main circuit, so they let you get away with not having the breakers for each.

 

[destructure00]

Gen 2 back in stock! Ordered!

Silver Wall Connector - Gen 2

Gloss Black Wall Connector - Gen 2

 

[jstjohnz]

Who says each Gen 3 ‘needs’ a separate breaker? That’s what it strictly has written down but how is that ‘required? It has no way of knowing what it’s connected to. We had this conversation when they came out and there is no way for a device to test for breaker capacity.

I have two Gen 2’s on a 100 amp circuit (load sharing) and they are set to max (80 amps). If I ever need to replace them with two Gen 3’s, they are getting set to max, of course. No issue here, because the 3’s are lower capacity but those with lower single shared circuit capacity can still use it on two Gen 3’s.

The single circuit for each is a good idea because you can then shut down one separately for repair. If you are starting from scratch, still recommended for that reason. But not to redo already installed wiring.

I agree that there is no apparent reason why 2 Gen 3s could not share a single 60A circuit if you were going to limit the total charging current to 48 amps. But that's about the only scenario where it would make sense.

 

[boaterva]

It’s obviously simpler to wire a separate circuit to each one and better for troubleshooting (so you can disconnect one at a time) but I was trying clarify that there was no reason per se to do. I suspect Tesla’s reasons are probably the same as I’ve stated, for simplicity. It’s also easier with the new lower limits on max current. A bit harder to do when you could have 72 per unit with Gen 2 and older cars!

 

[ecarfan]

Gen 2 back in stock! Ordered!

Silver Wall Connector - Gen 2

Gloss Black Wall Connector - Gen 2

Now out of stock, apparently. Glad you were able to get one.

I just moved from a house to a condo and brought my two Gen 2 chargers with me. My condo garage (specific to my unit) only has a 60A panel so was not able to install each charger on a separate circuit. My installer connected both of them to the 40A breaker in the panel that was wired to a NEMA 14-50 in my garage (all the condo garages in the building come standard that way). He removed the 14-50 and installed a box and ran conduit to each charger. So will be trying out the load balancing feature for my 3 and X. My wife and I don’t have a daily commute so we don’t put a lot of miles on our cars except for long summer trips towing our trailer. This new charging setup should be more than adequate for our needs.

 

[Rocky_H]

So will be trying out the load balancing feature for my 3 and X.

From looking at the pictures, I just see that one metal conduit going between the two wall connectors and through that box. Do you have the twisted pair signal wire inside that same conduit along with the power wires? Electric code does have a condition which makes that awkward. It says that if you are having signal wire and power wire sharing the same conduit space, that the signal wire insulation does have to meet the same voltage spec as the power wire insulation. Power wire insulation rating is usually I think 600V rated, and it's really hard to find thin twisted pair signal wire with that high of an insulation rating, although it does exist.

 

[ecarfan]

Hi Rocky; thanks for your post. Yes, my electrician told me that the signal wire he used met the insulation rating required. I don’t know where he sourced it from.

 

[Rocky_H]

Hi Rocky; thanks for your post. Yes, my electrician told me that the signal wire he used met the insulation rating required. I don’t know where he sourced it from.

Ah, great! It's a picky little requirement of code, but it does make for nice looking really clean installations like that if you can do it.

 

[ecarfan]

Here are photos of the signal wire used in my install, and photos showing how it is connected:

This is the connection to the charger I designated as the “slave”

And this is the “master”. It doesn’t matter which is which.

 

[jellybeans]

@destructure00 How did the second Gen2 work out for you? I’m in the same predicament, deciding between a eBay Gen2 or buy two Gen3s and sell my Gen2.

 

[destructure00]

@destructure00 How did the second Gen2 work out for you? I’m in the same predicament, deciding between a eBay Gen2 or buy two Gen3s and sell my Gen2.

It all worked fine. I never used both at the same time but I used both independently and they were good. FWIW I sold my car, and now moving from the house they were installed in, and the buyer wants them removed so I'll be selling both of them soon.