Complex install questions for 400A house

[Adrian Cockcroft]

@Vines mentioned SPAN.io as option for smart switching. Another option, would be something like shelly.cloud switches/relays. Might be better than span if your loads are distributed or they're not on a dedicated circuit. There is whole rabbit hole around products that work with Home Assistant.

The Shelly.cloud switches look interesting, but I think I need connected circuit breakers that I can pop into the existing sub panels for a few key circuits.
I have a home automation system that I can program to manage this, if I can figure out how to hook it up.

You mentioned backup heat which sounded like resistance heaters. Could upgrading/replacing the heat pumps be a cost effective option? It seems newer ones will rarely need backup heat in theory with most the climate in California

I have Monterey Bay coastal climate, and yes they do need backup heat at times.

 

[h2ofun]

The Shelly.cloud switches look interesting, but I think I need connected circuit breakers that I can pop into the existing sub panels for a few key circuits.
I have a home automation system that I can program to manage this, if I can figure out how to hook it up.

I have Monterey Bay coastal climate, and yes they do need backup heat at times.

Interesting, I am at 1500 feet. Mits mini split heat pumps. It gets into the 20's here. Never needed heat strips., These units work just fine when real cold. Now, if I were up the hill at 5 to 7 thousand feet, .....

 

[Adrian Cockcroft]

To automatically switch off circuits there are many different answers. The slickest answer is to use SPAN or something similar for the subpanels that contain breakers you want to turn off yourself. Other smart home solutions are possible, but I am not an expert. The Gateway does have the ability to shed one load when off grid through a dedicated 60v 1A DC contactor. This is usually an air-conditioner/heat pump through a dedicated thermostat control circuit. This circuit could be used to trigger other devices.

That's very useful info, if I understand that correctly, I can use the contactor to trigger my home automation, and interface from there to reduce load and shut down circuits.

 

[Adrian Cockcroft]

Interesting, I am at 1500 feet. Mits mini split heat pumps. It gets into the 20's here. Never needed heat strips., These units work just fine when real cold. Now, if I were up the hill at 5 to 7 thousand feet, .....

The heat pumps cycle on and off to avoid freezing up when it gets cold, and are working hard to heat a large space with high ceilings and solid concrete slumpstone block walls (excellent for fire resistance, but not good for keeping warm). I got the biggest option I could find, and we've also done a blower door test and sealed up the leaks as best we can.

 

[Adrian Cockcroft]

Are there any other loads in the subpanel with the PV solar system?

Yes, over half the house load is on that panel, kitchen (all electric), pool pumps, living area, guest house, three of the four heat pumps.

 

[Adrian Cockcroft]

The Eaton circuit breakers look plausible, they have up to 50A, with a documented developer portal. Smart breakers

Has anyone tried Eaton or something similar to shut off individual circuits during an outage?

 

[arnolddeleon]

The Shelly.cloud switches look interesting, but I think I need connected circuit breakers that I can pop into the existing sub panels for a few key circuits.
I have a home automation system that I can program to manage this, if I can figure out how to hook it up.

Some of the Shelly's could also be used just as a "switch" so if the device has Normally Open or Normally closed Switch that can be wired to then you can make the device "smart" with a Shelly (or similar). I actually haven't done this but it on my todo list for something like the pool pump. This avoids having to run the load through another device.

 

[Vines]

The Eaton circuit breakers look plausible, they have up to 50A, with a documented developer portal. Smart breakers

Has anyone tried Eaton or something similar to shut off individual circuits during an outage?

That would be an interesting project, and one I would appreciate someone else blazing the trail on.

Yes, over half the house load is on that panel, kitchen (all electric), pool pumps, living area, guest house, three of the four heat pumps.

Got it, so it is certainly not ideal to have 2 different Gateways, as only one of them would be able to recharge during an outage with the PV power. Also, 30k of PV power needs about 6 Powerwalls to take all that juice.

 

[Adrian Cockcroft]

That would be an interesting project, and one I would appreciate someone else blazing the trail on.

I'm surprised no-one else seems to have figured it out already...

Got it, so it is certainly not ideal to have 2 different Gateways, as only one of them would be able to recharge during an outage with the PV power. Also, 30k of PV power needs about 6 Powerwalls to take all that juice.

I think we're going to have 4 PW on the solar side, and 2 PW on the bedroom side. We get fairly frequent multi-hour outages, but if we get a multi-day outage, we can move to the guest house. Also, if in the future a 400A Tesla solution appears, swapping out the 2 gateways for one would be relatively simple. The worst case occurs in a storm in the winter, so the 30KW of solar wouldn't be producing full output...

 

[jjrandorin]

If this were me, I think I would be going with a different installer than tesla. Frankly, if this were me, I would likely be going a company that has a lot of experience (and desire) in building large, custom installs, and one which would be willing to answer all my questions till I was happy.

Since you are up in Northern CA, I would probably go with the company @Vines works for. Note that he is here just as a product owner, and is very careful to not mix those things (because he isnt a vendor) and gives a lot of his personal time to help people here just to help people so he never mentions this type of thing.

I also know that expertise costs, and am not aware of what the delta in pricing is, but when you start getting into larger, complicated installs, it seems to me that it would be more important than its exactly how you want it, vs trying to save a bunch of money on it (at least thats how I would approach it, at that size / scale).

Thats just how I would approach it, because if I had a house like that, and was looking at buying a PV that size, along with that many powerwalls, I would want to ensure everything was completely optimized and how I wanted it, and I would not want to trying to do that myself on an internet forum. I would be expecting the vendor I chose to do for me, and with me, explaining it to my satisfaction.

 

[Vines]

I'm surprised no-one else seems to have figured it out already...

I think we're going to have 4 PW on the solar side, and 2 PW on the bedroom side. We get fairly frequent multi-hour outages, but if we get a multi-day outage, we can move to the guest house. Also, if in the future a 400A Tesla solution appears, swapping out the 2 gateways for one would be relatively simple. The worst case occurs in a storm in the winter, so the 30KW of solar wouldn't be producing full output...

If you decide you want whole-home backup with all your resources in one Powerwall system PM me and we can discuss further options. It sounds like you are proceeding with Tesla Energy and best of luck to you in getting what you want.

You may need to consider how the 4 Powerwalls will charge from 30 kW of PV though. Each Powerwall can take only 5 kW charge maximum so 4 of them would have approx 10kW too much PV to be able to charge in off grid mode. I see you recently expanded your PV system so perhaps some or all of it is compliant with partial curtailment. If so, hopefully the frequency shifting feature of the GW2 will play nice with the 2 generations of PV. Perhaps as an option you can setup some smart home breakers to turn off the excess PV, when your ESS couldn't handle that charge. Otherwise, the Powerwalls will need to frequency shift your home in backup mode assuming you don't have a 10 kW baseline draw to turn that 30 kW of PV into 20 kW or less at the batteries.

Also as @jjrandorin pointed out expertise costs. I am here giving mine for free because I enjoy it and it seems a shame that so few professionals do. I have yet to see Tesla Energy here helping people out. Likely they are still participating here but not publically/obviously. If TE was here publically they probably would get stymied with customers needing service. They are able to be cheaper by skimping on the service and customer-facing overhead and also selling the PW units to a customer for about what they sell them to us for.

As far as the cost delta, it is probably $2-4k more per ESS installed once the SGIP is figured in to buy them from our company. In exchange, you get rapid service, access to really smart design professionals, quick PTO and access to the SGIP funds to keep the cost delta down between options. With 6 PW you would get half of your incentive in year 1 and the other half I think over the following 5 years. When just 5 ESS are installed like at my house the SGIP check is cut that year.

 

[h2ofun]

If you decide you want whole-home backup with all your resources in one Powerwall system PM me and we can discuss further options. It sounds like you are proceeding with Tesla Energy and best of luck to you in getting what you want.

You may need to consider how the 4 Powerwalls will charge from 30 kW of PV though. Each Powerwall can take only 5 kW charge maximum so 4 of them would have approx 10kW too much PV to be able to charge in off grid mode. I see you recently expanded your PV system so perhaps some or all of it is compliant with partial curtailment. If so, hopefully the frequency shifting feature of the GW2 will play nice with the 2 generations of PV. Perhaps as an option you can setup some smart home breakers to turn off the excess PV, when your ESS couldn't handle that charge. Otherwise, the Powerwalls will need to frequency shift your home in backup mode assuming you don't have a 10 kW baseline draw to turn that 30 kW of PV into 20 kW or less at the batteries.

Also as @jjrandorin pointed out expertise costs. I am here giving mine for free because I enjoy it and it seems a shame that so few professionals do. I have yet to see Tesla Energy here helping people out. Likely they are still participating here but not publically/obviously. If TE was here publically they probably would get stymied with customers needing service. They are able to be cheaper by skimping on the service and customer-facing overhead and also selling the PW units to a customer for about what they sell them to us for.

As far as the cost delta, it is probably $2-4k more per ESS installed once the SGIP is figured in to buy them from our company. In exchange, you get rapid service, access to really smart design professionals, quick PTO and access to the SGIP funds to keep the cost delta down between options. With 6 PW you would get half of your incentive in year 1 and the other half I think over the following 5 years. When just 5 ESS are installed like at my house the SGIP check is cut that year.

Lots of reasons to just go with 5 PW's. SGIP is one. The other is PGE has different rules when you go over 30K solar, or I believe 5 PW's

 

[Adrian Cockcroft]

If this were me, I think I would be going with a different installer than tesla. Frankly, if this were me, I would likely be going a company that has a lot of experience (and desire) in building large, custom installs, and one which would be willing to answer all my questions till I was happy.

Since you are up in Northern CA, I would probably go with the company @Vines works for. Note that he is here just as a product owner, and is very careful to not mix those things (because he isnt a vendor) and gives a lot of his personal time to help people here just to help people so he never mentions this type of thing.

I also know that expertise costs, and am not aware of what the delta in pricing is, but when you start getting into larger, complicated installs, it seems to me that it would be more important than its exactly how you want it, vs trying to save a bunch of money on it (at least thats how I would approach it, at that size / scale).

Thats just how I would approach it, because if I had a house like that, and was looking at buying a PV that size, along with that many powerwalls, I would want to ensure everything was completely optimized and how I wanted it, and I would not want to trying to do that myself on an internet forum. I would be expecting the vendor I chose to do for me, and with me, explaining it to my satisfaction.

Thanks for the advice. I've talked to the vendor who installed my solar, who aren't Tesla distributors but do install batteries, and who put in eGauges so I can see the actual power flows. I've also talked to the local Tesla PW distributor who is going to visit this week. After waiting for over a year for Tesla, I'm also reluctant to go to the back of the line again.

 

[Adrian Cockcroft]

If you decide you want whole-home backup with all your resources in one Powerwall system PM me and we can discuss further options. It sounds like you are proceeding with Tesla Energy and best of luck to you in getting what you want.

You may need to consider how the 4 Powerwalls will charge from 30 kW of PV though. Each Powerwall can take only 5 kW charge maximum so 4 of them would have approx 10kW too much PV to be able to charge in off grid mode. I see you recently expanded your PV system so perhaps some or all of it is compliant with partial curtailment. If so, hopefully the frequency shifting feature of the GW2 will play nice with the 2 generations of PV. Perhaps as an option you can setup some smart home breakers to turn off the excess PV, when your ESS couldn't handle that charge. Otherwise, the Powerwalls will need to frequency shift your home in backup mode assuming you don't have a 10 kW baseline draw to turn that 30 kW of PV into 20 kW or less at the batteries.

Also as @jjrandorin pointed out expertise costs. I am here giving mine for free because I enjoy it and it seems a shame that so few professionals do. I have yet to see Tesla Energy here helping people out. Likely they are still participating here but not publically/obviously. If TE was here publically they probably would get stymied with customers needing service. They are able to be cheaper by skimping on the service and customer-facing overhead and also selling the PW units to a customer for about what they sell them to us for.

As far as the cost delta, it is probably $2-4k more per ESS installed once the SGIP is figured in to buy them from our company. In exchange, you get rapid service, access to really smart design professionals, quick PTO and access to the SGIP funds to keep the cost delta down between options. With 6 PW you would get half of your incentive in year 1 and the other half I think over the following 5 years. When just 5 ESS are installed like at my house the SGIP check is cut that year.

Thanks for the advice, and sharing your expertise. The eGauges (installed last Nov on both sides of the house) show how much backfeed comes from the panel that has solar, pool pumps etc. on it, and it's less than 20KW in practice, but if we had everything in the house turned off in the mid-summer it would go over 20KW. We've got 3 older 7KW solar edge inverters and one new 10KW one, so maybe that one can handle partial curtailment.
My own background is physics/electronics/software and I have access to re-program our house's Vantage control system, and have built raspberry pi based controllers in the past for odd things like well depth monitoring at a previous house, so if I figure out how to connect something like the Eaton breakers to the PW I'll share that here.

 

[Adrian Cockcroft]

New funding for Span who seem to be working on the general problem of integrating panels and batteries etc. Span raises $90M to make smart panels the gateway to home…

 

[Vines]

Thanks for the advice, and sharing your expertise. The eGauges (installed last Nov on both sides of the house) show how much backfeed comes from the panel that has solar, pool pumps etc. on it, and it's less than 20KW in practice, but if we had everything in the house turned off in the mid-summer it would go over 20KW. We've got 3 older 7KW solar edge inverters and one new 10KW one, so maybe that one can handle partial curtailment.
My own background is physics/electronics/software and I have access to re-program our house's Vantage control system, and have built raspberry pi based controllers in the past for odd things like well depth monitoring at a previous house, so if I figure out how to connect something like the Eaton breakers to the PW I'll share that here.

Sounds good, if you want to get into the details about your system solution after Tesla provides you with plans that might be an interesting discussion too. I have done only some minor programming and haven't really stepped into the smart home devices yet.

 

[wwhitney]

The Gateway does have the ability to shed one load when off grid through a dedicated 60v 1A DC contactor.

You've been a bit coy about your 400A (2 x 200A) service solution with just one Backup Gateway. Are you using that contactor to control another Transfer Switch? Something like in the drawing below?

Cheers, Wayne

 

[Vines]

You've been a bit coy about your 400A (2 x 200A) service solution with just one Backup Gateway. Are you using that contactor to control another Transfer Switch? Something like in the drawing below?

Cheers, Wayne

I have been coy about it, as instructed by my boss.

Our solution is currently is a competitive advantage, that I am not sharing publically unless you are under contract with us.

 

[holeydonut]

I have been coy about it, as instructed by my boss.

Our solution is currently is a competitive advantage, that I am not sharing publically unless you are under contract with us.

Adrian Cockcroft needs to sign up with you all, so he can see this baller azz line diagram.

 

[Vines]

Adrian Cockcroft needs to sign up with you all, so he can see this baller azz line diagram.

He has well thought out this solution and it may work well just as envisioned. He has inertia with TE and hopefully the site visit goes well and inspires confidence that they have it under control. If not, we are in discussion about options.