Micro-Inverters and the Apocalypse

For those fans of “The Walking Dead”, you may have noticed a micro inverter in last night’s episode.  Therefore, we felt that it is a good time to talk about what a micro-inverter is.

In order to use the power from your solar panels for appliances and household electronics, you have to utilize an inverter.  An inverter inverts the DC power from the solar panels into AC power.  Currently, in the residential market, there are two types of inverters.  There is the string inverter and there is the micro-inverter.  While they both serve the same function in the end, they both do it in different ways.  With a string inverter, the groups of solar panels are wired together in series to form a string.  With a micro-inverter, each solar panel is connected to one micro-inverter.

Why the two options?  Both inverters have their merits and there downfalls.  A string inverter is the most cost effective way to go solar and if the string inverter fails, it is easy to replace.  The downside to a string inverter is that any shading on one solar panel in the string can seriously hurt the power production of that string.  A micro-inverter doesn’t have the shading issues of a string inverter.  If one solar panel is shaded, only that panel and inverter are reduced in power production.  The remaining solar panels will still perform.  With this same idea, if one micro-inverter fails, it doesn’t affect the rest of the solar panels and their production.  The downside to micro-inverters is both their cost and replacement.  Since micro-inverters are installed under the solar panels, it can be difficult to replace them.

In the next article, we will discuss how shading impacts a solar array in more detail.  At least now, you know what a micro-inverter was doing in the apocalypse.

Technology doesn’t trump a quality design

It bothers me to see how often technology is used to counter a poor system design.  It just doesn't make any sense.  And often times, the technology isn't being used for its actual purpose.

A prime example of this is charge controllers.  A charge controller is a device that takes the input power from the solar module and regulates the output.   By doing this, a charge controller can provide the right type of energy required by your battery.  More advanced charge controllers can actually assist in the maintenance of the battery itself. 

So far so good!  However, the charge controller's efforts are really only as good as the overall system design.  The available energy of a system is not based on the battery capacity.  The true limiting factor in available energy is the solar module production.  The solar module is the fuel for the battery.  A charge controller cannot compensate for a lack of energy production.  You must properly pair your solar module production with your battery.  Otherwise, your result will be deficit cycling.  Or in simple terms, you have a battery that just won’t last.