[RE-wrenches] Inverter ratings exceeding 25kw fir battery backup

Tue Feb 18 14:54:44 PST 2025

Proceed with caution, feel free to contact me off list.

On Tue, Feb 18, 2025 at 5:36 PM Jason Szumlanski via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Don't even get me started on that. I have a library that wants a PV system
> and batteries just to operate the elevators in the event of an outage. It's
> 120/208V. We are seriously looking at a Sol-Ark 30K.
>
> On Tue, Feb 18, 2025, 5:27 PM Jerry Shafer <jerrysgarage01 at gmail.com>
> wrote:
>
>> Elevators, it's all about the Elevators
>>
>> On Tue, Feb 18, 2025, 2:24 PM Jason Szumlanski via RE-wrenches <
>> re-wrenches at lists.re-wrenches.org> wrote:
>>
>>> 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 <matt at 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-bounces at 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 at lists.re-wrenches.org>
>>>> *Cc:* Jason Szumlanski <jason at 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 at 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/ <https://offgridsolar1.com/>  <http://members.sti.net/offgridsolar/>*
>>>>
>>>> *e-mail  offgridsolar at sti.net <offgridsolar at 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 at 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/ <https://offgridsolar1.com/>  <http://members.sti.net/offgridsolar/>*
>>>>
>>>> *e-mail  offgridsolar at sti.net <offgridsolar at 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 at 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/ <https://offgridsolar1.com/>  <http://members.sti.net/offgridsolar/>*
>>>>
>>>> *e-mail  offgridsolar at sti.net <offgridsolar at 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. I would appreciate to hear any experiences or similar
>>>> interactions with PGE or PPL or even how this has worked in other
>>>> jurisdictions, states, etc. Any input or support is greatly appreciated.
>>>>
>>>>
>>>>
>>>> Tyrone Houck
>>>>
>>>> Oregon Solarworks LLC
>>>>
>>>> CCB #204937 LRT #076
>>>>
>>>> 541-787-1366
>>>>
>>>> tyrone at oregonsolarworks.com
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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