<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"></div><div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">You're right on the string sizing. My mistake. I was thinking IQ6+ vs IQ7+.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Mac makes a great point about the AC output rating and utilities. While the de facto (arbitrary) AC to DC ratio is 0.85x for the interconnection tier determination in Florida, I have one Co-Op that has agreed on a case by case basis to use the actual inverter output rating if it drops them down a tier, saving costs, insurance requirements, and the requirement for a disconnect switch. A 1.3x ratio means a 0.77x factor from the utility's perspective rather than 0.85x.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">FWIW, we have a lot of 1.3x ratios on M190s monitored out there. I have found no correlation between failure rates based on module watts. Admittedly, there were lots of M190 failures in general, but I don't see the ratio as a determining factor.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Jason</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><b><div style="text-align:center"><br></div></b></div></div></div></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Oct 7, 2020 at 10:09 AM Mac Lewis <<a href="mailto:maclewis1@gmail.com">maclewis1@gmail.com</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"><div dir="ltr">Hi Jay,<div><br></div><div>This is where a modeling program can really help. We use Helioscope to model these (they let you try it for free) and extract the true benefit of the more expensive inverter. Like Jason says, it's really all about the environment, tilt & orientation etc. I have found there is also a psychological component to a customer to see them clipping even if your annual production estimates are right on. I haven't seen evidence that Enphase life is compromised by overpowering them for many hours per day, but we will see over time if that's true. Most of the time for non-ideal roof mounts, we have found that an IQ7 will really lose very little energy annually compared to the IQ7+. Like Jason, we have found no real reason to use the IQ7A.</div><div><br></div><div>There are other things to consider. For example, we have a utility that puts fixed limits on the size of a solar system based on AC output of the inverter. Oftentimes, dropping to an IQ7 allows a larger DC system and thus more kWh to be produced. Stringing can change as well.</div><div><br></div><div>Also, Jason according to the spec sheet you can put 16 of the IQ7 as opposed to 13 of the IQ7+ on each string but maybe I misunderstood you.</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Oct 5, 2020 at 5:42 PM Jason Szumlanski <<a href="mailto:jason@floridasolardesigngroup.com" target="_blank">jason@floridasolardesigngroup.com</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"><div dir="ltr"><div style="font-family:arial,helvetica,sans-serif"></div><div dir="ltr"><div style="font-family:arial,helvetica,sans-serif">It depends on climate, orientation, and other factors. Here it is really hot almost all the time. We rarely experience anything close to the max power rating of a module here. If the orientation isn't ideal, that's another argument for oversizing. Around here we use 385 and 390W 72-cell modules on the 290W IQ7+ and rarely see clipping that would outweigh the advantages and cost-efficiency. Incidentally, early indications from some low temp coefficient 360W modules show that they do quite well compared to 385W modules with more standard coefficients this time of year. I need more data on that to make a real assessment. And modules with low temp coefficients tend to be pricey.</div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">I am very comfortable with 1.3x - 1.4x here in Southwest Florida using standard modules. Elsewhere I would expect the ratio to be somewhat lower. I have no justification for the IQ7A here at this time.</div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">P.S. My CED Greentech rep shared some Helioscope data using the IQ7 (not plus) and 360W 120-half-cell REC Alphas. There is only a marginal advantage to using the IQ7+ over the IQ7 in that scenario here. I still opt for the IQ7+ since it is marginally better when considering cost and performance and it is more compatible/flexible. Since it's the same max quantity per string, I don't see the point in dropping to the IQ7 for the price difference.</div><div style="font-family:arial,helvetica,sans-serif"><br></div><div style="font-family:arial,helvetica,sans-serif">Jason Szumlanski</div><div style="font-family:arial,helvetica,sans-serif">Florida Solar Design Group</div><div style="font-family:arial,helvetica,sans-serif"><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Oct 3, 2020 at 8:08 PM Jay <<a href="mailto:jay.peltz@gmail.com" target="_blank">jay.peltz@gmail.com</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">Hi all<br>
<br>
For those working with Enphase. <br>
How hard are people recommending pushing the DC/AC ratio?<br>
<br>
Enphase has some pretty convincing data that even a 400 watt module on a 240watt inverter has very small clipping vs annual production <br>
<br>
Given that why would i recommend to a customer the IQ7A at 360va and quite a bit more expensive vs the 240va IQ7? <br>
Location would have something to do of course, tilt, yes. <br>
But it seems that unless you\u2019re installing a really large module or their data is wrong, I\u2019m not sure I see the advantage of the larger inverter?<br>
<br>
I\u2019m hoping there will be some counter views. <br>
<br>
Thanks<br>
Jay<br>
Peltz power. <br>
<br>
<br>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr"><div><br></div><div><font color="#305A78" face="'times new roman', serif"><br></font></div><div><br></div>Mac Lewis<br><br><span style="font-family:"Times New Roman";font-size:medium;color:rgb(255,153,0)"><b><font face="Arial, Helvetica, sans-serif" size="3"><p align="left"><font color="#000000" face="Verdana, Arial, Helvetica, sans-serif"><span style="font-size:small"><span style="font-family:arial;font-weight:normal;color:rgb(48,90,120)"><font face="'times new roman', serif">"Yo solo sé que no sé nada." </font><span style="font-weight:700;color:rgb(104,104,104)"><font face="'times new roman', serif">-Sócrates</font></span></span></span></font></p></font></b></span></div>
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