SolarEdge system design Insights

Solar PV System Design:

As you have been reading my blog, you will see that SolarEdge is the only Inverter/Optimizer/PV harvesting system that makes any sense at this current time.  When ever you have more than 16 or so panels on an inverter, you should always use two strings.  I have come up with 4 good reasons for doing so.

4 Reasons to use 2 Strings per Inverter

The min number of panels per string is 8 and the maximum is  around 28 (25 SE).

1.0 By running two strings you reduce your power losses in your wires by 50%.  That could save you as high as $1500 over 20 years.

2.0  Having 2- 10 string panels verse 1 20 panels on a string will allow you to easily expand your system without much difficulty.  A 10 kW system would still be limited by the inverters.  That is how every other power plant is designed.  You can not track the sun's path, but you can increase your gross harvesting and help slow the CO2 growth. 

3.0  I was recently informed that the optimizer can fail and take out the circuit.  This would be a rare event but two strings will reduce your cost to find the faulted optimizer, improving maintainability. Optimizers when they rarely fail, normally fail without taking out the circuit.  I don't know how they are wired but an internal meltdown would most likely take the string down.  Don't worry about this but design the maintainability by using two strings.

4.0  Having two strings, the Inverter just works better at controlling the power curve.  A very good reason in it self for having two strings.  SolarEdge recommend two strings.

The only down side is if your panels are covered with so much snow that you will not turn on.  We clean our panels in the winter so that the system keeps working all year so that is not a problem for us.

Your installer may try to tell you that two strings are not needed.  You don't have enough experience to tell them other wise.  They just want to save the cost of wire and labor.  Put 2 strings per Inverter in you Engineering Specification for the above reasons for maintainability and overall system performance.  Makes sure that it is part of your contract in writing before you sign the contract.  If people want, I can post my Engineering Specification.

One Smart Designed Inverter

If you have enough solar panels to exceed the rated output of the Inverter that is a good thing.  The Inverter just turns the panels off that it doesn't need until it needs the power.  It does NOT dump the power to a resister and the Inverters always run cool, even in the summer on a hot day. It does another thing also.  The range of the DC voltage is 350 to 500 V.  When it detects that it is operating at maximum the Inverter increases the DC voltage from around 365 V to under 450 V.  The reason it does this is to reduce the amount of current flow, not power coming into the Inverter.  When you shut off the system, you still get 1 V per panel so the system is safe for Firefighters.

There is one very rich guy in Windsor who runs 25 microfit programs.  A few years back, he removed all of his systems and installed solaredge with some 40-50 panels per system.  He harvests the maximum that he can and gets paid the 80.2 cents per kW and not the current under 39 cents.  He would earn around $400,000 per year estimated or 20 MW per system per year.

I hope that these insights will assist you in getting the maximum out of your system.  The world is in really bad shape due to high CO2 levels, see my other blog.  

Go Solar.