Solar Experimenting

by Ben N on April 9, 2017

Spring is Sprung!
It was the first Saturday of spring with some actual nice warm sunny weather, so that means it’s time to experiment with solar!

A couple of weeks ago, I got a few used Enphase micro-inverters in the mail. My buddy, Russ, (https://www.youtube.com/user/rwg42985) had found some inverters at an electronics salvage yard near him. He tried testing a few, but wasn’t able to get them to work. After doing a little research, I found conflicting reports on whether or not this type of inverter was usable at all without first “commissioning” it with an IT device. Since I was planning on ordering Enphase’s Envoy for my system anyways, I just went ahead and ordered one.

I had also already purchased a pair of Helios 260w solar panels. (The Helios brand was manufactured in Milwaukee, Wisconsin, about 30 miles from my house.) So, with solar panels, micro-inverters, Envoy, and a sunny day, there was nothing stopping me from hooking them all up and making power!

IMG_3503One last part of the Enphase micro-inverter system is a special cable with quick connectors on it that the micro-inverters plug in to. I bought a section of that cable with two connectors on it at the same time as the Envoy. I picked up some parts from the electric aisle of the Home Improvement store to wire the cable up to a junction box and a NEMA 14-50 plug. That’s a heavy 240V connector that’s common at RV parks. It also happens to be the style of electric outlet I have in my garage for my electric car charging cord (EVSE.)

IMG_4004The first step was to get the Envoy up and running. The device is an internet gateway. It communicates with the micro-inverters to set up the system and then output system data to the web change settings and view solar energy production information. The Envoy communicates with the inverters over the power line. That means that the device has to be connected to a “clean” outlet. You don’t want to plug the power cord into a surge protector or a circuit with any electric motors or anything else that can muddy the signal. I happen to have a dedicated outlet right next to my household breaker box which I was using with my T.E.D. whole-house energy monitor. (The T.E.D. uses a similar style Data-Over-Power communications system.)

IMG_4012I downloaded Enphase’s “Toolkit” app to my smartphone. I could then communicate from my phone to the Envoy over wireless to set it up. One of the first things was a software update. That took at least a good 20 minutes. Enphase recommends installing the Envoy and having all software updates done before connecting any micro-inverters. Setting up the Envoy with the app was straight-forward. The app even included a few brief videos showing an installer exactly what to do.

Back out in the garage, I propped my two solar panels against the wall and into the sunlight. The micro-inverters were already plugged in to the solar panels. I only had to plug the inverters into the trunk cable, and then plug that into the wall with the NEMA 14-50 plug. I then flipped on the breaker for that circuit.

At that moment, I was NOT producing any solar power. The inverters have several safety features. A big feature is “Anti-Islanding”. The inverter must sense that it is connected to grid power. If it doesn’t, the inverter instantly shuts down. This prevents the solar panels from pushing electricity out to the grid during a black0ut. Once power is restored to the grid, there’s still a timeout feature that prevents the micro-inverter from generating power for five minutes AFTER good clean power is restored. (The inverter also will not output if grid power is out of voltage or frequency range, such as in a brown-out.)

So, although I just turned on the circuit breaker for the inverters, the solar panels wouldn’t make power for another five minutes. After that though, the small green LED on the inverters was flashing green, indicating that all was functioning correctly. In the Enphase Toolkit app, I could see how much power I was making from each panel. (I also used the clamp-on ammeter feature of my multimeter to check current flowing through the trunk cable.)

Screen Grab half day of solarOnce the system “commissioning” was done, I could then take a look at my power production through Enphase’s “Enlighten” software. The Envoy pushes data from the inverters out to the web, allowing the solar owner to view production information on it from anywhere in the world. A person can also make that data public (if they so wish) so that friends can see how much solar power is produced as well.

By actually connecting all these components, I have a much better sense of how they work, and how I’ll create my full-blown home photovoltaic system. Still, there’s a few quirks…

For one thing, two of the three salvaged inverters use H4 connectors. These are supposed to be interchangeable with the MC4 connectors on the solar panels, but they are just a tad different. For the life of me, I can’t figure out how to unplug them! I have all the various H4 and MC4 unlock tools, but they just don’t seem to work! If anyone has ever done this, please let me know how!

IMG_4011I’m also trying to decide exactly which inverter I want to purchase. M215 and M250 inverters are basically named for how many watts of power they can handle. One would assume that a 260 watt solar panel is more powerful than a 250 watt inverter, but this isn’t necessarily true. For one thing, a panel rated at 260 watts is in “ideal laboratory conditions”… which seldom happen in the real world. In my experimenting so far on a sunny morning, manually tilting solar panels to match the angle of the sun, I wasn’t often getting all that much more than 200 watts per panel. (At one point, I did hit 235 watts!)
The M250 inverter is designed to handle 240w maximum continuous, while the M215 handles 215 watts continuous, 225 watts peak. (And yet I hit 235 watts using a 215 inverter!)
It would appear that M215 inverters might be just fine with these 260 watt solar panels, and they cost less than the M250s. For a more technical angle on why, take a look at Enphase’s white paper on this. It’s an interesting read. Let me know what you think of it. (You can read that paper at: https://enphase.com/en-us/support/technical-brief-sizing-solar-modules-microinverters)

Looks like I’m getting very close to actually buying my solar panels and ordering racking and inverters. Some of the best mail-order prices for solar components can be found at Renvu (http://www.renvu.com). At this point, I’m planning on ordering inverters from them, but will probably get my racking locally to save on shipping costs.

Until next time, stay charged up!

-Ben

{ 2 comments… read them below or add one }

1 Nick Soleil April 11, 2017 at 3:55 pm

Hi Ben,

The orange Enphase ET-DISC disconnect tool has the prongs on it to release the Amphenol H4 or MultiContact MC4 DC connectors. Have fun!

2 admin April 19, 2017 at 7:48 pm

I have the orange Enphase disconnect tool, and have had no luck with that either.
I believe that the problem is that TOGETHER the two different connectors don’t work quite right! I’ve still had no luck disconnecting these two, no matter what I’ve tried.

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