Tag: "string inverter"

08/27/13

  12:48:00 pm, by Jim Jenal - Founder & CEO   , 552 words  
Categories: Residential Solar, Ranting

Try Doing That with a String Inverter!

There is a vigorous debate among solar installers about the relative merits of microinverters, such as those made by Enphase Energy, versus those of string inverters, such as those made by SMA. We can’t claim that we have resolved that debate once and for all, but our experience this past week reaffirms our confidence in the microinverter choice.

Almost exactly a year ago we did a residential installation at a seriously shaded site.  We explained in detail to the homeowners about the reduced yield that any solar power system would provide given just how much shading they had, but they were still eager to press forward.  The shading mandated that we use microinverters, and they were excited to see how their system would perform using the Enlighten monitoring system.

In addition to the shading, there was another limitation - a 150 Amp service meant that we couldn’t install as big a system as they needed.  However, they were about to embark on a six-month renovation of the home and as part of that they were going to upgrade the service.  We decided to build the first half of the system right away and include the additional infrastructure that would be needed for the later addition - down to the standoffs on the roof.

Here’s how the install looked a year ago:

First phase of project completeAs you can see from the photo, there really is substantial shading present - and you can also see our Unirac standoffs waiting for Phase II.  Sitting on top of those Enphase M215’s are LG 250 Watt solar modules - our preferred product at that time.

Fast-forward to this past week.  We are still using M215’s but LG has moved up the curve and the new modules for the second phase of this project are 280 Watts each.  The homeowner wanted the higher power modules incorporated into the existing system, and they wanted them installed not on the open bottom row, but wherever they would be able to get the greatest amount of sun to maximize their return on investment.

The first great advantage of having microinverters on this project then was the ability to combine significantly different power modules into the same array.  But the second goal - placing the new modules in the ideal locations - was one that we could only solve with confidence thanks to the Enphase Enlighten data.  Indeed, all we had to do was go to the monitoring page for this site and request the display of lifetime energy.  Here’s how that looked:

lifetime energyNow isn’t that interesting?  There is a huge difference going from the NW corner down to the SE.  Overall, taking the top row along with the three west-most modules from the second row seemed like our best plan.

Here is how the expanded array looked after we completed the install:

expanded arrayPretty easy to see where the new panels were installed - they are the bright shiny ones!  (The break in the bottom row is to avoid the utility service mast.)

Here is how the new system performed yesterday (after the old panels were cleaned!):

yesterday's energy yieldOur higher power modules are installed in the optimal locations, thanks to the ability to mix and match modules in the array, combined with the ability to know at the module level where are our best performing slots in the array.

Trying doing that with a string inverter!

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06/12/11

  11:04:00 am, by Jim Jenal - Founder & CEO   , 321 words  
Categories: All About Solar Power

Why is the Enphase M215 So HOT?

Enphase M215 micro-inverter

The newest micro-inverter from Enphase Energy - the M215 - is now available and we believe that this will be one hot product.

We have been fans of Enphase micro-inverters for some time and we have installed numerous Enphase systems, particularly at shady sites.  We liked how the independence of each panel/inverter helped boost energy yield, we were dazzled by the brilliant monitoring abilities of the system, and we were real fans of the 15-year warranty (compared to the standard 10-year warranty on string inverters.)

So why do we think the new model will be such a step up?  First and foremost is the upgrade on the warranty to 25 years!  No other inverter manufacturer offers anything comparable as their standard warranty.  This means that the key components of the array - the solar panels and the inverters - will now have warranties of identical duration.  We believe this is a huge step forward in building client confidence in the fundamental reliability of solar power systems.

Second, the M215 has improved its CEC efficiency rating to 96% making it the match of any of the popular string inverters.

Third, the M215 should be easier to install as it now only requires a single bolt to attach it to the array racking and its new cabling system should allow for a smoother installation process which will help to drive down costs.

Finally, the M215 is compatible with some of the more powerful solar panels out there, such as the Suntech 225.  We believe that the pairing of the Suntech panels with the M215 will be a great fit for many of our residential and smaller commercial clients.

Put it altogether and we believe that the Enphase M215 has the potential to be a real game-changer.  If you have been wondering when would be the right time to add solar to your home or business, the M215 is one more reason why the right time to add solar is NOW!

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Jim Jenal is the Founder & CEO of Run on Sun, Pasadena's premier installer and integrator of top-of-the-line solar power installations.
Run on Sun also offers solar consulting services, working with consumers, utilities, and municipalities to help them make solar power affordable and reliable.

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