Choosing a wrong solar inverter can affect the power output

Yes, choosing a wrong solar inverter can affect the power output. Inverter is a device which converts the direct current produced by the solar photovoltaic panels or electrochemical power system such as battery, to alternating current using which majority of our electric  gadgets work.

Also the inverter produces high voltage alternating current from the low voltage DC produced from the above sources.

Whether electricity produced by solar panels is to be used for domestic applications or industrial applications or to feed the grid, inverter is needed.

How to choose a solar inverter?

There are different types of inverters.  Their cost varies with the extent of conditioning of the DC produced.

Based on the signal characteristics of the current produced the inverters are classified as

  • Square wave inverter
  • Sine wave power inverter.

Square wave power inverter is the cheapest.  But the square wave produced is less desired as it does not guarantee steady voltage output.  Sine wave power inverters produce current closely matching in characteristics to that of alternating current and hence preferable for operation of all types of electrical equipments.

Based on the methods of operation, the solar inverters are classified as hybrid inverter, solar power conditioning unit and grid inverter.

The hybrid inverter allows charging of the battery using sunlight during day time and grid during low or no sunshine hours.  Solar power conditioning unit senses the charge/discharge state of the battery and uses grid or solar panel for charging the battery.  If the battery voltage is in the range of 10.5 – 14.5V, solar charging mode of the inverter operates.

If the voltage is less than the low cut-off or more than the high cut-off, grid charging of the battery occurs.  Generally the conversion efficiency of the inverter is about 80%.  The grid inverter directly feeds solar electricity to the grid.  As it does not have the battery component, the cost of the system is low.  Industries prefer the grid inverter.  Grid inverters convert the DC power to AC of required voltage in order to feed the Grid.  Also, to increase the voltage, few inverters can be connected together.

The first step in the choice of the solar inverter is the load calculation taking into account the power requirement of lights, fans and other electrical gadgets.  The inverter should be 30% more than the total power of all the loads.  Based on the solar insolation, time and duration of peak loads, suitable type of inverter listed above can be chosen.