<div dir="ltr"><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I think you are talking about a dual meter scenario for grid interconnection (separate buy/sell meters). If that is the case, I would avoid grid interconnection altogether. The utility company doesn't need to know what you're up to. The benefit from grid selling would be so small that it would not really matter unless the array was very large relative to the load. As Zeke suggested, just set this up as a no-sell site and use the batteries for maximum <span style="background-color:transparent">self-consumption. If PV is being lost and the battery reaches the stop discharge limit routinely, suggest more battery capacity.</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="background-color:transparent"><br></span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="background-color:transparent">The EG4 12000XP is a good option for this scenario. It does not grid sell. It's just like a UPS when paired with a battery, but it can be used to self-consume solar. The flagship EG4 inverters can be set up this <span class="Asgive ng" style="border-style:none;background:none">way as well,</span><span class="Asgive ng" style="border-style:none;background:none"> but</span> cannot guarantee there will be no leakage back to the grid (if large loads suddenly shut off during high solar production, especially if the battery is full).</span></div><br clear="all"></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><br>Jason Szumlanski<br>Principal Solar Designer | Florida Solar Design Group<br>NABCEP Certified Solar Professional (PVIP)<br>Florida State Certified Solar Contractor CVC56956<br>Florida Certified Electrical Contractor EC13013208<br></div><div><br></div><div><br></div></div></div></div><br></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Sat, Jun 27, 2026 at 8:21 AM Christopher Warfel via RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
<div>
<p>Thanks Zeke, I just saw this and will respond with some ideas.
Chris</p>
<div>On 6/26/2026 6:06 PM, Zeke Yewdall via
RE-wrenches wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>This sounds like the old buy all sell all system with two
meters. I didn't realize any utilities were still doing
this. But the way that we'd do it on a grid-tie system was
have one meter measuring production that then connected into
the grid on the utility side of the meter going to the house.
During a sunny day, the energy used by the house would first
be sold to the utility through the production meter, then
bought right back through the normal loads meter.</div>
<div><br>
</div>
<div>Doing a battery backup system would, I think, be wired up
the same way. The PV array would have its own grid-direct
inverter selling power to the grid, and then the battery
backup system would draw power from the grid for charging --
it would be set up as a UPS type system, not knowing that any
solar existed at all.</div>
<div><br>
</div>
<div>If the grid went down, you would not be able to power the
house or charge the batteries from the solar, as it would be
connected on the dead grid side of any transfer switches from
the backup power, and I think this would meet the utilities
intent -- if the grid is down, they cannot purchase any
electricity, so therefore, generating electricity to recharge
your batteries or use would not be allowed.</div>
<div><br>
</div>
<div>Frankly, if faced with a tarriff like this, I would
seriously look into what it would take to get rid of the grid
connection entirely and do an actual off-grid system. I
figure that most batteries right now cost about 4 to 5
cents/kWh for energy stored then used. So it would depend on
the load profile and how much was used during the daytime and
how much at night, but if the buy rate is more than 2 or 3
cents more than the sell rate, I would think it would be
cheaper to invest in batteries and pay 0 markup during the
daytime, and 4 or 5 cents battery cost at nighttime, rather
than paying more than 2 or 3 cents markup all the time.</div>
<div><br>
</div>
<div>Usually, even when faced with very unattractive buy/sell
rates, I still recommend that people maintain their grid
connection, even if only to use it in place of a standby
generator fill in during winter weather. Even paying a
$50/month standby charge to maintain a grid connection you
almost never use can be cheaper than maintaining an actual
physical generator. But if you aren't allowed to even use
your own solar power on site without incurring their markup,
then that could be a different story.</div>
<div><br>
</div>
<div>Zeke</div>
<div dir="ltr"><br>
</div>
<div dir="ltr">On Fri, Jun 26, 2026 at 10:39?AM Christopher
Warfel via RE-wrenches <<br>
<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>
wrote:<br>
<br>
> > Our local utility has a requirement that ALL
generation be sold to them<br>
> at avoided cost, and that ALL purchases be made at tariff
rate. A couple<br>
> of years ago before installing an EG4 system (which I did
my first one this<br>
> past year), I told the president of the coop that I did
not think that was<br>
> possible with multi mode systems. I've tried a lot of
different settings<br>
> in the EG4 but it seems not to make a big difference.<br>
><br>
><br>
> Does anyone have knowledge of how to do this? Signature
Solar did not<br>
> have a definitive answer, and what we have tried so far,
has not really<br>
> produced the results I was hoping for.<br>
><br>
><br>
> Thank you, Chris<br>
><br>
> ><br>
> --<br>
> Christopher Warfel, PE<br>
> ENTECH Engineering, Inc.<br>
> PO Box 871, Block Island, RI 02807<br>
> (401) 447-5773</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Jun 26, 2026 at
1:13 PM <<a href="mailto:re-wrenches-request@lists.re-wrenches.org" target="_blank">re-wrenches-request@lists.re-wrenches.org</a>>
wrote:<br>
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<br>
Today's Topics:<br>
<br>
1. How to sell maximum amount from EG4 (Christopher
Warfel)<br>
2. Re: How to sell maximum amount from EG4 (Dave Tedeyan)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Fri, 26 Jun 2026 10:36:32 -0400<br>
From: Christopher Warfel <<a href="mailto:cwarfel@entech-engineering.com" target="_blank">cwarfel@entech-engineering.com</a>><br>
To: <a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a><br>
Subject: [RE-wrenches] How to sell maximum amount from EG4<br>
Message-ID:<br>
<<a href="mailto:adcab7b2-1d88-4896-af75-3bc90406546d@entech-engineering.com" target="_blank">adcab7b2-1d88-4896-af75-3bc90406546d@entech-engineering.com</a>><br>
Content-Type: text/plain; charset=UTF-8; format=flowed<br>
<br>
> Our local utility has a requirement that ALL generation
be sold to them at avoided cost, and that ALL purchases be
made at tariff rate. A couple of years ago before
installing an EG4 system (which I did my first one this past
year), I told the president of the coop that I did not think
that was possible with multi mode systems. I've tried a lot
of different settings in the EG4 but it seems not to make a
big difference.<br>
<br>
<br>
Does anyone have knowledge of how to do this?? Signature
Solar did not <br>
have a definitive answer, and what we have tried so far, has
not really <br>
produced the results I was hoping for.<br>
<br>
<br>
Thank you, Chris<br>
<br>
><br>
-- <br>
Christopher Warfel, PE<br>
ENTECH Engineering, Inc.<br>
PO Box 871, Block Island, RI 02807<br>
(401) 447-5773<br>
<br>
<br>
<br>
------------------------------<br>
<br>
Message: 2<br>
Date: Fri, 26 Jun 2026 10:42:53 -0400<br>
From: Dave Tedeyan <<a href="mailto:dave@sungineersolar.com" target="_blank">dave@sungineersolar.com</a>><br>
To: <a href="mailto:cwarfel@entech-engineering.com" target="_blank">cwarfel@entech-engineering.com</a>,
RE-wrenches<br>
<<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br>
Subject: Re: [RE-wrenches] How to sell maximum amount from
EG4<br>
Message-ID:<br>
<CAM3Q7f1Qsbhpi=<a href="mailto:hO6BXe8nkQH-WvLkHrJSSm-B_-rK_AW9FnVw@mail.gmail.com" target="_blank">hO6BXe8nkQH-WvLkHrJSSm-B_-rK_AW9FnVw@mail.gmail.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
You can try contacting EG4 directly. I've had good luck
talking to them as<br>
well when I have had questions. They were good about helping
me derate the<br>
grid sell for a couple inverters to stay below our utilities
residential<br>
limit, and then signing a form for us to give to the
utility.<br>
<br>
Cheers,<br>
Dave<br>
<br>
On Fri, Jun 26, 2026 at 10:39?AM Christopher Warfel via
RE-wrenches <<br>
<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>
wrote:<br>
<br>
> > Our local utility has a requirement that ALL
generation be sold to them<br>
> at avoided cost, and that ALL purchases be made at
tariff rate. A couple<br>
> of years ago before installing an EG4 system (which I
did my first one this<br>
> past year), I told the president of the coop that I did
not think that was<br>
> possible with multi mode systems. I've tried a lot of
different settings<br>
> in the EG4 but it seems not to make a big difference.<br>
><br>
><br>
> Does anyone have knowledge of how to do this?
Signature Solar did not<br>
> have a definitive answer, and what we have tried so
far, has not really<br>
> produced the results I was hoping for.<br>
><br>
><br>
> Thank you, Chris<br>
><br>
> ><br>
> --<br>
> Christopher Warfel, PE<br>
> ENTECH Engineering, Inc.<br>
> PO Box 871, Block Island, RI 02807<br>
> (401) 447-5773<br>
><br>
> _______________________________________________<br>
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</blockquote>
</div>
<div><br clear="all">
</div>
<br>
<span class="gmail_signature_prefix">-- </span><br>
<div dir="ltr" class="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">Zeke Yewdall
<div>PV Engineer</div>
<div>NABCEP #031508-89</div>
<div><a href="mailto:zeke@darkforestsolar.com" target="_blank">zeke@darkforestsolar.com</a></div>
<div>303-523-3592</div>
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<pre cols="72">--
Christopher Warfel, PE
ENTECH Engineering, Inc.
PO Box 871, Block Island, RI 02807
(401) 447-5773</pre>
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