Microinverter Power Performance Test
April 13, 2021
As we like to do at SKYLIT, we’ve tested the inverters we use (Hoymiles) to make sure they perform as expected, so that we can be confident that we are providing the best possible quality hardware for the systems we put our name on. This microinverter power performance test is number three in our technical blog series; you can read about our Solar Racking Test and our Solar Panel Performance Test as well.
A bit about Solar Power Conversion
The power produced by solar panels is DC (direct current), whereas your home uses AC power (alternating current). So to use the power generated by solar panels, you need to convert the power with a current inverting device. There are two options for doing this – with a string inverter or with microinverters. Microinverters are a more efficient form of conversion, have about double the lifespan of a string inverter so in the long run cost less, have much better warranties (ours are 25 years), and are safer as you aren’t bringing heavy DC current into your house – instead the power is converted right at the solar panel. They are also equipped with other built in safety features to automatically shut them down if they sense changes in the grid voltage, or if the grid goes down entirely.
For the reasons outlined above, we use microinverters for all residential applications; and even for large commercial systems, like the one we did at the Old Orchard Inn, they are often the most appropriate technology.
A bit about Peak Power Output
Current inverting devices are the heart of the solar power conversion to AC. Inverter manufacturers have defined the peak rated AC power output; these values can be found in the products’ datasheets. The higher the rated AC output the better, a high peak AC power output means that the inverting device is able to handle and feed into the grid a larger amount of power produced by the solar panels.
Here is the rated Peak AC Power Output for different microinverters (latest version released on the market):
The current Hoymiles HM Series microinverters we are using in our installations are 3% more powerful than other leading market competitors. So do they perform as well as the manufacturer claims? Read on to find out!
The Microinverter Power Performance Test
We conducted the microinverter AC power performance test using two high precision DC variable voltage power supplies to simulate the solar power, feeding on average 325W DC to each channel of a Hoymiles 600W dual channel microinverter. Then we measured the peak power output with a third-party certified energy meter, the Brultech Green Eye Monitor (GEM). This is the same energy meter used by the Nova Scotia Community College Applied Energy Research Lab for researching purposes.
The objective of this test was to stress the microinverter by making it work at its max power output, verifying in real-time the AC power produced, while also measuring the accuracy of the Hoymiles monitoring system.
The Results of the Microinverter Power Performance Test
Peak AC power output of the Hoymiles MI-600 is rated at 600W (300W/channel).
According to the Hoymiles monitoring system, the inverter was feeding 611.4W into the grid, around 2% more than expected:
The Brultech Green Eye meter recorded a stable AC power production of 609W, around 1.5% more than expected:
The difference in the values registered by the Hoymiles monitoring system and the energy meter was only 0.4%. This is a high grade of accuracy, given that the monitoring system is not considered “revenue grade”, and gets its information via Zigbee wireless technology.
So there you have it! The results of the microinverter power performance test shows that the Hoymiles microinverters we use produce more power than expected. And when paired with the premium LG solar panels that produce 5.6% more power than competitors (as we found in our Solar Panel Performance Test), choosing SKYLIT as your solar provider means you’ll have a top of the line, high performance system that is built to last!