Another option may be a main breaker, bypass breaker interlock kit in the non-backed up panel. The home would obviously be limited to 200A total during an outage but, if he doesn’t mind going and swapping Cybertruck chargers he may also not mind going down to the basement and hitting the interlock kit to turn off the main and turn on the bypass on the non-backed up panel. I’ve heard of an 800A home that operates on that principle. I think the three non-backed up (or maybe non-instantaneous) panels are fed by 60A circuits off the backed-up panel. Savvy clients only….
Matt From: RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> On Behalf Of Jason Szumlanski via RE-wrenches Sent: Tuesday, February 18, 2025 5:22 PM To: RE-wrenches <re-wrenches@lists.re-wrenches.org> Cc: Jason Szumlanski <ja...@floridasolardesigngroup.com> Subject: Re: [RE-wrenches] Inverter ratings exceeding 25kw fir battery backup Caution: This email originated from outside SES. Do not click links or open attachments unless you recognize the sender and know the content is safe. Yes, but the PV system would need to be split, and inevitably, the balance of PV and battery assigned to each distribution panel will not match up well at times. A single battery and a single PV system serving the entire property is what he really wants. Tesla is not the answer for that today. I suggested converting the dual 200A service to a single 400A service and using 4-6 Midnite AIOs, but that would get pretty messy. I do like the idea of having two wall connectors for this purpose. That didn't cross my mind. I could possibly convince him to do a GW3/PW3 system for one 200A panel and just a Powershare for the other panel (without PV recharging). It depends on what is on each panel I suppose. The Powershare is only 110A LRA, so it might not start up larger AC units without soft start. The whole idea isn't too practical, but he wants to explore all options. Also, as of today, Powershare does not work with the Gateway 3 with Powerwall 3. They are working on an OTA firmware update to support this. For now, it's just unidirectional charging from the Wall Connector. You need the Gateway 3V for Powershare to work, but that does not work with Powerwall 3, so it's a waiting game. Jason Szumlanski Principal Solar Designer | Florida Solar Design Group NABCEP Certified Solar Professional (PVIP) Florida State Certified Solar Contractor CVC56956 Florida Certified Electrical Contractor EC13013208 On Tue, Feb 18, 2025 at 5:12 PM Matt Partymiller <m...@sesre.com<mailto:m...@sesre.com>> wrote: Jason, Sounds like an interesting market. A transfer switch is probably more expensive than two Tesla vehicle chargers, one for each system. He just needs to remember which one to plug into and you just need to sell at least 4 PW3s, a couple gateways and you’re in business…. Matt From: RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org<mailto:re-wrenches-boun...@lists.re-wrenches.org>> On Behalf Of Jason Szumlanski via RE-wrenches Sent: Tuesday, February 18, 2025 5:05 PM To: RE-wrenches <re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>> Cc: Jason Szumlanski <ja...@floridasolardesigngroup.com<mailto:ja...@floridasolardesigngroup.com>> Subject: Re: [RE-wrenches] Inverter ratings exceeding 25kw fir battery backup Caution: This email originated from outside SES. Do not click links or open attachments unless you recognize the sender and know the content is safe. Not bragging, but many of my clients in this situation are billionaires or at least some sizable fraction of that. Naples is a pretty interesting place. They are usually not willing to compromise. On the three barrier islands where I do off-grid work, it always starts off as a few mini-splits and then it ends up being a few mini-splits and a 5-ton central. And then they install an electric hot tub unbeknownst to me. And then there are three electric golf carts that show up. And how can you enjoy the beach with 30 of your favorite friends without a large ice maker (on top of the undercabinet unit at the outdoor wetbar)? It never ends. For on-grid homes with common 400A service (dual 200A panels) we focus on backing up one panel while installing enough PV to cover the total annual household usage, which is usually the request we get. They would love to back up both panels, but when confronted with the space requirements and battery capacity limitations imposed by NFPA 855, the conversation usually goes my way. As for the PV portion, we always hear that if they can't cover 100%, they don't see the point in doing it. That's why you end up with giant PV arrays with battery capacities more typical of a modest home. I just spent an hour explaining to a customer with an existing 25kW Enphase system why he can't back up two 200A panels with Tesla Powerwall 3's (without serious drawbacks associated with splitting the PV and battery). He was also under the impression that he could use Powershare from his Cybertruck to back up both 200A panels simultaneously, or at least switch easily between them (I actually toyed with the idea of a transfer switch to accomplish this, but decided to just say no). These clients don't hear NO often. On the other hand, they are usually very smart and ask good questions. Most of them didn't get rich by accident. Jason Szumlanski Principal Solar Designer | Florida Solar Design Group NABCEP Certified Solar Professional (PVIP) Florida State Certified Solar Contractor CVC56956 Florida Certified Electrical Contractor EC13013208 On Tue, Feb 18, 2025 at 2:38 PM Dave Angelini Offgrid Solar via RE-wrenches <re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>> wrote: Still Jason it seems very crazy! When I do energy for a home in your neck, usually offgrid, we use mini-splits and in a large home like you are referring with the grid, the same thing, use a split for a zone, like the kitchen and save all that wasted battery capacity backing up the whole home. They may be a bit uncomfortable without the grid but they can survive a hurricane outage, or longer. The strategy of not backing up it all does require the people to be reasonable and trainable. Very few central air systems are useable without spending 10's of thousands more. I think none unless the owner has more money than brains. Good for the economy I guess but all that lithium has to go to the dump someday. Seems alot of lithium is going to the dump with all these companies building batteries and then going out of business also. Alot of my calls are for systems that the installer has long gone out of business. The owner is clueless because they never had a clue about their power system. No Bueno for sure! Stay Safe ! Dave Angelini Offgrid Solar "we go where powerlines don't" <http://members.sti.net/offgridsolar/> https://offgridsolar1.com/ <http://members.sti.net/offgridsolar/> e-mail offgridso...@sti.net<mailto:offgridso...@sti.net> text 209 813 0060 On 2025-02-18 9:42 am, Jason Szumlanski via RE-wrenches wrote: Haha, we would not have the pool heater on a backup system, but many times people want a partial home backup system with whole home annual grid offset. But for practical purposes around here, full-time residents often just trade pool heating for air conditioning based on season. If you size a backup system for central air conditioning, sometimes it is technically possible to heat the pool off-grid in the winter because the house load is otherwise a fraction of what it is in the summer months. In the winter, we sometimes see batteries full by 9:00 am and a lot of wasted solar energy. Jason Szumlanski Principal Solar Designer | Florida Solar Design Group NABCEP Certified Solar Professional (PVIP) Florida State Certified Solar Contractor CVC56956 Florida Certified Electrical Contractor EC13013208 On Tue, Feb 18, 2025 at 11:56 AM Dave Angelini Offgrid Solar via RE-wrenches <re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>> wrote: Sure I get how important it is to electrically heat a pool in a power outage. 😉 Dave An,gelini Offgrid Solar "we go where powerlines don't" <http://members.sti.net/offgridsolar/> https://offgridsolar1.com/ <http://members.sti.net/offgridsolar/> e-mail offgridso...@sti.net<mailto:offgridso...@sti.net> text 209 813 0060 On 2025-02-18 8:05 am, Jason Szumlanski via RE-wrenches wrote: There are many 4,000 sq ft pool homes in my area with electric pool heating and electric everything else where 25kW would just cover the electric bill. Some larger homes around here can definitely require more. Florida Power & Light allows up to 50kW on 120/240V split phase service, but only if expected production does not exceed an estimated 115% of historical annual usage. Jason Szumlanski Principal Solar Designer | Florida Solar Design Group NABCEP Certified Solar Professional (PVIP) Florida State Certified Solar Contractor CVC56956 Florida Certified Electrical Contractor EC13013208 On Mon, Feb 17, 2025 at 12:58 PM Dave Angelini Offgrid Solar via RE-wrenches <re-wrenches@lists.re-wrenches.org<mailto:re-wrenches@lists.re-wrenches.org>> wrote: Why is there a need for more than 25KW for residential please? Just curious. In Nevada, 25KW is way into commercial. Dave Angelini Offgrid Solar "we go where powerlines don't" <http://members.sti.net/offgridsolar/> https://offgridsolar1.com/ <http://members.sti.net/offgridsolar/> e-mail offgridso...@sti.net<mailto:offgridso...@sti.net> text 209 813 0060 On 2025-02-17 9:43 am, Tyrone Houck via RE-wrenches wrote: Greetings wrenches, In Pacific Power territory we are coming up against roadblocks with regards to whole house battery backup systems with inverter ratings higher than 25kw. Even when the generation capacity is below the 25kw residential limit, net metering applications are being rejected based on the inverter rating.. The inverter rating in these cases is sized to handle the customer's existing loads and will never export more than the 25kw limit dictated by Oregon PUC. I am drafting a letter to Energy Trust, the state, etc. But am curious if anyone else gas had this problem or come up with a solution. 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