Has anyone fed TWO 200amp subpanels from ONE 200amp disconnect using ONE Gateway?

[mzairboy]

I have a 30kW solar array and want to install 2-4 Powerwalls. We live in an old stone farmhouse, so for ease of running wires there are two 200 amp panels inside the house.
We never draw close to 200 amps even with everything powered on including heat, hot water, kitchen, car charging, all lights, etc.
The house is supplied with a single 200amp disconnect wired off our main 600 amp panel. This is a farm, so the main panel distributes to the entire property.
I'd like Tesla to backup the 200amp disconnect, as that would provide whole home backup, but they don't want too because that disconnect feeds the two 200 amp sub panels.
They say it can be done, but they don't like it so they won't. They want to instead break down the 4 Powerwalls into 2 gateways.
Doing this would require I rewire my solar into 2 feeds to split to each gateway evenly, and since the Powerwalls are split I lose capacity.
Having 1 Gateway and multiple Powerwalls gives me extra power capacity to the whole home backup, and extra storage for my oversized solar array.
Smaller energy storage will start and stop charging during a grid disconnect event, where as more capacity allows more charging and discharge.

To add insult, Tesla Energy doesn't know how Powershare will integrate into their system at all. They hope I could save cost and only purchase 2 Powerwalls and the Cybertruck will act as an additional 3-5 Powerwall storage capacity when plugged in, but they don't know any details at this time.

For now, I'm trying to start with a Powerwall system until my Foundation Series truck arrives in the next 90 days.
Has anyone ever fed two 200amp subpanels off a primary 200amp disconnect with a single gateway?

 

[CrazyRabbit]

I ran into the same resistance. Ended up combining two 40 circuit panels into a 80 circuit panel.
They are idiots, but they got their thumb on the scales.

 

[Vines]

View attachment 1011348

I have a 30kW solar array and want to install 2-4 Powerwalls. We live in an old stone farmhouse, so for ease of running wires there are two 200 amp panels inside the house.
We never draw close to 200 amps even with everything powered on including heat, hot water, kitchen, car charging, all lights, etc.
The house is supplied with a single 200amp disconnect wired off our main 600 amp panel. This is a farm, so the main panel distributes to the entire property.
I'd like Tesla to backup the 200amp disconnect, as that would provide whole home backup, but they don't want too because that disconnect feeds the two 200 amp sub panels.
They say it can be done, but they don't like it so they won't. They want to instead break down the 4 Powerwalls into 2 gateways.
Doing this would require I rewire my solar into 2 feeds to split to each gateway evenly, and since the Powerwalls are split I lose capacity.
Having 1 Gateway and multiple Powerwalls gives me extra power capacity to the whole home backup, and extra storage for my oversized solar array.
Smaller energy storage will start and stop charging during a grid disconnect event, where as more capacity allows more charging and discharge.

To add insult, Tesla Energy doesn't know how Powershare will integrate into their system at all. They hope I could save cost and only purchase 2 Powerwalls and the Cybertruck will act as an additional 3-5 Powerwall storage capacity when plugged in, but they don't know any details at this time.

For now, I'm trying to start with a Powerwall system until my Foundation Series truck arrives in the next 90 days.
Has anyone ever fed two 200amp subpanels off a primary 200amp disconnect with a single gateway?

The size of the subpanels is not the issue, the size of the circuit to be backed up is the issue. If you have any, what do your load calculations say about the actual load on that 200A circuit?

I see your drawing includes both the Backup Switch and the Gateway and I don't totally understand why. Typically with a 200A feed and an (assumed) 240 volt split phase 600A service I would design this with a Tesla gateway so that my system could backfeed to the non backup loads while the grid is up. However the backup switch could work as well with a bit less functionality. If you have a 3 phase service then this is more complicated.

It is common to have a 200A panel fed by a 100A breaker, and there is no reason except the practical that you couldn't feed a 400A or 600A panel with a 100A or 200A breaker.

As to the powershare question, this is still an unknown to many people so no surprise there is confusion on your project.

 

[mzairboy]

The size of the subpanels is not the issue, the size of the circuit to be backed up is the issue. If you have any, what do your load calculations say about the actual load on that 200A circuit?

I see your drawing includes both the Backup Switch and the Gateway and I don't totally understand why. Typically with a 200A feed and an (assumed) 240 volt split phase 600A service I would design this with a Tesla gateway so that my system could backfeed to the non backup loads while the grid is up. However the backup switch could work as well with a bit less functionality. If you have a 3 phase service then this is more complicated.

It is common to have a 200A panel fed by a 100A breaker, and there is no reason except the practical that you couldn't feed a 400A or 600A panel with a 100A or 200A breaker.

As to the powershare question, this is still an unknown to many people so no surprise there is confusion on your project.

We have been monitoring the house for months with maximum power draw. (Every light, appliance, house, car charging, hot water flowing, freezers open and running to cool, etc) We are well under the peak loads and have shown this to Tesla. They understand it can be done, they just choose not to do it.

I threw the gateway and backup switch in there because I wasn't totally sure which way it would be wired, but it kind of gets the point of flow across.

This is not 3 phase service, but it is a farm so the main load center panel distributes to many buildings. I'm only concerned about home backup, which is 2 of the 200amp panels inside. One in the garage and one in the basement, due to 2' thick stone walls and wiring constraints. If those 2 panels were both 100 amps Tesla would wire this in a heartbeat. But because they were oversized by the electrician, Tesla is afraid in theory I could pull 200 amps on each, totaling 400amp draw, so they won't do it. They told me in an overdraw situation the Powerwalls would simply shut down. I'm perfectly fine with that. But they won't install, even though my total loads are well under the thresholds of a single 200amp gateway.

 

[ucmndd]

Can you downrate the two sub panels to something less than 200 amps? Swap out the main breakers for 100 or 125?

Sounds like your setup is complicated and you might need to explore third party installers. Tesla usually doesn’t want to do anything out of the ordinary or even slightly complex.

 

[mzairboy]

Can you downrate the two sub panels to something less than 200 amps? Swap out the main breakers for 100 or 125?

Sounds like your setup is complicated and you might need to explore third party installers. Tesla usually doesn’t want to do anything out of the ordinary or even slightly complex.

Yes, it is more complex that cookie cutter, but easily done. Tesla even said they can do it, they just don't want to. I have a few electricians that would do it for me, but Tesla won't sell them the hardware.

 

[BGbreeder]

Tesla is extremely cookie cutter based on the shared experiences here. You appear to have an atypical installation, so they opted to pass as it, like many others doesn't "fit". In the postings here, rarely get Tesla to change the decision not to install, though some folks have had some luck on design details. I suspect that this is the end of the road for you with Tesla. (But feel free to read the many threads here on Tesla declining installations to see if there is anything that might help you.)

Since you seem to want to integrate a cyber truck into an already atypical installation, I would suggest not doing anything for awhile to let the dust settle. If you want it now, I would explore third party Tesla installers and other battery choices.

 

[mzairboy]

Tesla is extremely cookie cutter based on the shared experiences here. You appear to have an atypical installation, so they opted to pass as it, like many others doesn't "fit". In the postings here, rarely get Tesla to change the decision not to install, though some folks have had some luck on design details. I suspect that this is the end of the road for you with Tesla. (But feel free to read the many threads here on Tesla declining installations to see if there is anything that might help you.)

Since you seem to want to integrate a cyber truck into an already atypical installation, I would suggest not doing anything for awhile to let the dust settle. If you want it now, I would explore third party Tesla installers and other battery choices.

Agreed, even Tesla said they don't know how to integrate Powershare at this time with Cybertruck and Powerwall. Based on the Powershare webpage they think I could purchase 2 Powerwalls instead of my planned 4 Powerwalls, and then plug my truck into the system to add an additional 123kwh worth of battery capacity when the Cybertruck is connected to the system. This would work great for me with a 30kW solar array to maximize charging potential during an "off grid" situation and would allow me to run the house longer as well.

I have solar at work too, so I can go to work, charge my Cybertruck full during the day from the sun, and go home and plug the sunshine into my Powerwall system and power my home during the evening. The 2 Powerwall would give short run time during power blips or when my truck is not at home. In an extended outage I would keep my truck plugged in to the system and opt for another vehicle if necessary.

There is a lot of potential here, if they figure out how to integrate it.

 

[CrazyRabbit]

Can you downrate the two sub panels to something less than 200 amps? Swap out the main breakers for 100 or 125?

Sounds like your setup is complicated and you might need to explore third party installers. Tesla usually doesn’t want to do anything out of the ordinary or even slightly complex.

You don’t need to as long as 200 amp breaker is installed in TEG

 

[ucmndd]

You don’t need to as long as 200 amp breaker is installed in TEG

Sounds like you don’t necessarily need to in any case, it’s less about need vs. trying to find something that Tesla may be comfortable with completing.

 

[travwill]

I have two 200 amp panels so we split with 2 gateways. Had to evenly split solar and 2 power walls on each system. Wished could have had one system though.

 

[jjrandorin]

and go home and plug the sunshine into my Powerwall system and power my home during the evening.

Probably not unless you disconnect from the grid, as I think the powershare setup is only off grid (meaning i think its only designed to be used when off grid / grid down).