The use of Enphase IQ7A microinverters in my smart home solar installation project means that each panel is generating an ac voltage, rather than a dc voltage. It allows each panel to function and be monitored independently using the Enphase Envoy hub and the Enphase Enlighten app (or the Enphase website) for monitoring. This approach also avoids shaded, damaged or failed panels having an impact on the rest of my generation capability.
As well as generating power, the microinverters communicate with an Enphase hub using powerline communications. The hub then acts as an IP gateway to my home network and the Internet.
These are the many reasons why I chose to use Enphase Microinverters in my smart home solar installation project:
The main (perceived) downside of using microinverters is the cost but, when you compare performance, features and the monitoring tools available, the cost difference is negligible in my view. I would recommend and install Enphase microinverters every time. Replacing a failed microinverter can be a more complex process, requiring scaffolding but, I'm confident this will not be an issue.
It is worth saying a few words about over sizing and clipping as it is very common practice in the UK solar industry. The 'over sizing factor' (sometimes called the over sizing ratio) is the peak output of your solar panels divided by your inverter capacity. In my installation the 17 × 390W solar panels could generate a peak output of 6.63kW under perfect conditions. In practice, the output is limited by the microinverters to 17 × 349W = 5.933kW continuous. This would result in an over sizing factor of 111.7%. Generally, it is not advisable to to exceed 130%. In practice, I've had days where the solar panel output has reached 6.1kW.
The reason for over sizing is that solar panels are the relatively cheap part of any installation and they are hardly ever in the ideal conditions required to hit their peak output, due to the angle of the incident sunlight on the panels, the roof inclination, the ambient temperature, shading, etc. In the winter, the panels will not get close to their peak output due to the sun being so low in the sky. For this reason, having more panels than the inverter(s) can handle, allows you to generate more energy, more of the time.
In an ideal world, you would avoid clipping completely, so that you have the highest possible peak power to use for many things (EV charging, appliances, etc.) but, this would simply cost more and make the payback period longer. As the customer, it is entirely your choice though.
Our home is located in Suffolk (East Anglia, UK), one of the sunniest and driest parts of the UK. Our house faces 160° South (i.e. 20° to the East of South) and the roof is inclined at 50° and has no shading. This means it is ideally orientated for solar PV energy collection according to this orientation calculator. We have 17 Trina 390W solar panels installed, each with an Enphase IQ7A microinverter.
Enphase microinverters are connected to the Enphase Envoy hub, which has a wired Ethernet network interface on my installation. It can use Wi-Fi though. This allows the Enphase Enlighten app to provide energy usage insights, remote update capabilities and load management.
The hub has a number of useful status and error lights on the front, which make it very easy to check that everything is working as expected.
On completion of your installation, the installer will generate an email invite to download the Enphase Enlighten app. This will make your installation visible for monitoring.
The primary screen in the app is a status view, showing current power being produced and stats for today and yesterday.
People often associate microinverters (and optimisers) to installations that have partial shade but, in practice the sunlight on my panels also varies slightly as the sun comes up and goes down. This vertical variation up and down my panels can be seen on winter mornings. The microinverters ensure optimum power is delivered from each panel.
The app shows daily total energy generated per panel.
I'm assuming it is standard MCS practice but, I don't know for sure. My installer put a physical isolation switch in the loft and also put another one on the end of the cable coming down from my loft, inside my garage. They also put a fused switch inline with the power feed to the Envoy hub. This makes a lot of sense to me.
I've been amazed with the performance of my smart home solar installation project. As you can see from my data analysis, my energy generation levels are very high for a 6.63kW installation.
My system also has an exceptional Monthly Generation Factor, something I'm confident my Enphase microinverters make a big contribution to.
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