Choosing the right inverter for your PV system
If you’re setting up a solar array, you will need to choose an inverter. An inverter is the piece of electrical equipment that turns DC power coming from solar panels into AC power, which is the usable power in your home or business. This can be done in variety of ways.
String inverter:
One single piece of equipment the solar panels lead into before connecting to your electrical panel. It converts the power from all solar panels as one to AC before being used.
The advantages of a string inverter:
- An older and more established technology, string inverters are generally cheaper than micro-inverters
- Easy to replace if there is a warranty issue
- There are additional technologies like power optimizers, which help solve most of the disadvantages, though there are almost always trade-offs
The disadvantages of a string inverter are:
- You may lose significant power production if a few of the panels are shaded or have dirt on them
- The inverter is sized to the system, so it is not easy to expand add more panels
- Monitoring equipment sees the system as a whole, so you can’t assess individual panel performance
Micro-inverters:
Similar to a string inverter and a DC power optimizer wrapped into one smaller package. The conversion happens right at the module level behind every one or two panels.
The advantages of microinverters:
- Individual panel monitoring
- Easy to expand
- Arguably a safer technology
Disadvantages of microinverters:
- Too new to tell if they will outlast string inverters, as they haven’t been around long enough
- The cost is higher for a microinverter
There are many types, sizes, brands, and models of inverters. Various options are also available. Choosing which one is best from such a long list can be a chore. There is no “best” inverter for all purposes – what might be great for an ambulance would not be suited for an RV. Power output is usually the main factor, but there are many others to consider such as watts, watt hours, amps, power ratings of the inverter. They are further classified as sine wave, modified sine wave and square wave inverters based on their power output.
