Microinverters or “Micros” have many advantages over traditional string inverters like Fronius. In this blog we explore the costs and advantages over string inverters.
Firstly though if Solar is new to you, then learn how solar works.
Firstly releasing the M175 Enphase microinverter in 2008. Secondly the M190 which saw the sales take off and Enphase solidify their place in the market.
Following this success Enphase have established themselves as an industry leader. Consequently they have a majority market share in the North American solar market.
In Australia they are now a leading alternative option to string inverters. Furthermore Enphase are having great success with the partnership with SunPower.
What is a Microinverter?
In string inverter systems, the inverter converts DC power to AC at the inverter.
However Enphase microinverters attach to each solar panel. Therefore each panel works independently from the rest of the system. Resulting in DC power being converter to AC immediately on the roof.
Advantages of Enphase Microinverters
The main advantage of microinverters is optimising each panel to generate the greatest amount of power.
From time to time solar panels generate varying amounts of power. Especially if there is shade, dirt and mismatch as explained below.
In a standard string installation, the panels connect together in series. Resulting in the power output of the string normally determined by the lowest performing panel. A single dirty, shaded or generally poor performing panel can effect the performance.
However using micro’s help overcome these issues. Resulting in avoiding the many reasons solar systems can under-perform including:
- Shading – Trees, buildings, poles, wires, antennas, or any rooftop structures
- Soiling – Dust, snow, bird droppings or birds
- Panel mismatch – various manufacturing tolerances
- Panel faults – micro cracking, hot spots or water ingress
- Temperature difference – thermal mismatch at different times of the day
- Panel Ageing – Panel degradation at different rates over time
- No PID – Eliminates Potential Induced degradation
- Odd roof layouts – Panels mounted at multiple orientations and angles
- Small roof – Roof area’s which can only fit a small number of panels
- No single point of failure
- Not limited by string voltages
- Easily expanded with different or newer panels
Microinverters increase performance, allow for complex roof installs and improve safety. Furthermore they eliminate single points of failures.
Enphase Microinverter Range
Two groups of microinverters are available from Enphase. The seventh-generation IQ7 series and the new eighth-generation IQ8 series.
Enphase IQ7 Microinverter
This has been due to larger and more powerful solar panels coming onto the market. Therefore the IQ7A has a higher continuous power rating of 349VA. Compared to the previous 320V on the IQ7X.
However unlike the IQ7X, the greatest DC input voltage is 58V. Which is compatible with the latest 60 and 72 cell, or 120 and 144 half-cut high powered solar panels up to 460W. The 96 cell panels, such as those from SunPower, are compatible with only the IQ7X.
Enphase IQ8 Microinverter
Grid forming allows the solar system to operate independently of the grid. Resulting in the solar system functioning in a black out even without a battery.
The Enphase IQ8 series are available in a large range of sizes. Designed to suit specific panel sizes and voltages. Especially the more powerful commercial solar panels rated up to 550W.
Claimed as “the industry’s first grid-forming microinverters”. The Enphase IQ8 range is available in a range of sizes from 240VA up to 380VA. Resulting in a Enphase microinverter option for almost all types of solar panels.
Furthermore the Enphase IQ8 series specialises in speed and accuracy. Enabling the microinverters to operate in both on and off grid mode.
Finally the new IQ8 series works seamlessly with the new range of Enphase battery storage equipment. Which includes, the IQ Gateway, IQ Battery and IQ system controller.
Enphase Envoy and Enphase Enlighten
Overall Enphase microinverters offer a better system monitoring when compared to string inverters. Primarily because each panel can be monitored individually. Comparatively string inverter systems would need DC optimisers to achieve this visibility.
Also, the installer has a separate login where they can track their “fleet” of Enphase installs. Therefore installers also get notified of under-performing systems. This can help prevent system downtime and help with any warranty claims.
Furthermore Enphase can track all the installed systems worldwide. Providing valuable information on fault conditions and ability to improve their products.
Enphase Microinverter Reliability
Evidently there have been low failure rates reported from solar installers. Therefore Enphase has proven to be one of the most reliable manufacturers in the world.
During the 2014 summer in Adelaide the most consecutive days over 40C occurred. Due to Enphases tracking ability of inverters they stated. “No Enphase Micro inverter across Australia shut down due to high temperature”
In a microinverter system, panels produce DC power but the conversion to AC occurs on the roof.
Importantly voltage from DC electricity is more likely to cause overheating or a fire if any cables become damaged.
However it is important to know that fire from any solar system is very unlikely.
AC Solar Modules
AC solar modules are solar panels with built in microinverters. Originally SolarBridge was the leading AC solar module manufacturer. However in 2014 SunPower, the market leading Solar panel manufacturer acquired their business.
Following this in 2018 Enphase bought out Sunpower’s microinverter business. Resulting in a partnership where Enphase now provides the microinverters for the panels.
Consequently Enphase and SunPower, both leaders in their field, produce the leading SunPower Maxeon 6 AC solar panels.
Resulting in better speed in solar installations. Less points of failure and microinverters optimised for the solar panel at creation.
Disadvantage of Enphase Microinverters
- Price – Costs are higher than average string inverters
- Additonal points of failure – Due to multiple microinverters being needed
- Exposure to extreme conditions on the roof
- Limited ability to integrate with existing solar batteries
If you are looking for a safe, high quality and high performing solar system. Then Enphase microinverters are the best option.
For roofs with many orientations or shading issues, micros are the smart choice.
Micro Inverters do have a higher upfront cost in comparison to string inverters. Therefore if you are on a budget and have a large roof area with no shading issues, then a good quality string inverter will be more cost effective.
Microinverters are not a great option for those looking at DC coupling batteries. However, this is changing with the release of the new Enphase IQ energy storage system.
Overall Enphase is the best microinverter supplier on the market. This is due to the solid track record, high quality production and low failure rate.