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

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Insulation Day!

by Ben N on March 15, 2017

We got most of the insulation in today! And by “We”, I mean the crew that I hired.

After running the numbers on the cost of just buying insulation, plus the trips to and from the big box store, it doesn’t actually cost all that much more to hire some pros to do it.

IMG_3563The crew from Dakota Insulation was two guys in a box truck. They quickly unloaded several large bales of fiberglass and got to work.

The previous Saturday, I already cleared nearly everything out of the garage. I had to get everything off the walls and floor to make room. Too bad we also had a winter storm in the weather forecast. I moved all the ladders, lumber, and other supplies outside, and covered them with a tarp. They were then buried under the snow.

The insulation is pretty typical for stick built construction in my area. It’s R-19 fiberglass in the 2×4 walls. We already installed a layer of 1/2″ foam on the exterior of the building. That acts as a wind-break, a little additional insulation, and weather-proofs the exterior until we get the siding on. (Which will be easier to do in nicer weather.)

In areas thicker than a 2×4, R-38 insulation is used. For example, above the can lights in the upstairs ceiling is filled with R-38 batts. There’s also foam vents that space the fiberglass away from the roof and allow air to move from the soffits, under the roofline, all the way up to the peak to escape at the ridge vent. This allows for full air circulation OUTSIDE the insulated envelope. It prevents moisture build-up from condensation in the winter, and prevents attic overheating in the summer.

Over the top of the fiberglass is a plastic vapor barrier. All the seams were taped. Anywhere that was too small to fit insulation, but air might be able to infiltrate, was caulked to stop those air leaks. For example, between adjacent doubled-up studs. I also used the flexible version of Great Stuff around the service door and the windows before the insulators arrived.

The work was all finished in less that three hours, but that was only the Fiberglass Batts portion of the insulation.

IMG_3574The ceiling of the garage (floor of the loft) will get a nice thick layer of BLOW-IN insulation. The main reason is that the insulation can be much thicker, and even go right over the tops of the bottom chord of the trusses. That board is a 2×10 (which is actually 9.25 inches tall.) Under the floor of the loft, that full 9+ inches will be filled in solid with the blow-in insulation. In the side attics the insulation can go thicker, so we can get 13 inches of insulation in place. The blow-in insulation uses different equipment, including a truck-mounted blower and hoses. Because of that, it will be a different crew some other day to take care of the blow-in part of the project.

Already, the garage SOUNDS very different, as the fiberglass absorbs much of the echo in the downstairs. When I climbed the ladder to the loft, I could feel it was already warmer. Also, the upstairs is now completely out of the wind. (Downstairs, there are still no garage doors in place!) The upstairs also feels much smaller, as I no longer have the long sight lines of looking through the stud walls all the way to the edge of the building.

IMG_3573I cut through the plastic vapor barrier at the NEMA 6-50 outlet so that I could re-mount my Level 2 EVSE electric car charging station.

At this point, I’m now waiting a few days for the blow-in crew. I’m also waiting to hear back from the Power Utility about the paperwork I turned in a few weeks ago for my Solar P.V. proposal. Lastly, somebody from the garage door company is supposed to stop by and check the door opening measurements in preparation for the garage door installation.

Having ANY insulation in place feels like a big step forward. I’m hoping to get some of the plywood interior walls done soon too, but much of that simply depends on my work schedule, which is very tight right now.

Until next time, Stay Charged Up!

-Ben

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Insulation, Doors, and Solar Cables

by Ben N on March 11, 2017

IMG_3493

Two weeks ago, I got the bid from the insulation company. Because of their economy of scale, and having a nice box truck and other equipment handy, the insulation company can insulate my garage for not a whole lot more than if I went to the big box home improvement store and bought insulation to do it myself.

Because the “Loft” upstairs of the garage is basically the attic, I’m limited in how much space I have for insulation up there. However, in the FLOOR of the loft, the bottom cord of the truss is a 2×10. I’ll be able to put in almost 10 inches of blown insulation in there to keep the heat in the downstairs. Yesterday, I called them back up and put in the order to proceed with the installation. The insulators will be out this next week. It will probably take MORE than one day, but not by a whole lot. Apparently, these guys are pretty quick.

As much as I LOVE the idea of a “super-insulated” garage, one of the big practicalities is simply the budget, along with physical space. I’m also only planning on heating the garage to about the lowest level I can. The lower the temperature difference between the outside and inside, the less insulation needed. Super-insulating might be nice, but does’t make sense if all my heat leaves when I open the garage door to move a car in or out! That said, I’m looking through all the nooks, crannies, and penetrations and sealing them with expanding foam before the insulators get here.

IMG_3494

I also stopped by the garage door installation company – Hartland Overhead Door. It’s one that my father’s construction business always used, and it happens that I know the two sons who now run that family business from high school. I got a quote for two doors of the 2″ thick urethane-foam filled variety. The price was identical to a 2″ foam door at the big box store, except that with the full-service garage door company, it includes installation!

Before I left, one of the owners, Joe, stopped back in, so I got to say “Hi” to him. I explained what I’m trying to do with the solar panels and how I’d like to integrate some sort of “sunny winter day” glazing into the garage. (Perhaps something like this – BuildItSolar Link) On the demo in their shop, Joe showed me a pull-down screen door for garages. It was a very simple design with one vertical piece of track, one horizontal, and a rigid aluminum frame that holds the screen. I pondered the possibility of getting something like that, only without the screen, and installing twin-wall polycarbonate instead.

I believe that this is the screen that I saw. I didn’t ask about price while I was at Hartland Overhead Door. Later, I tried finding an online retailer to check pricing. It was nearly $1,000 for the screen door, no matter which size! Yipes! The design did look simple, so maybe I can make my own from scratch?

Lastly, a friend of mine is sending me a couple of USED micro-inverters. He found them at an electronics salvage yard. We have no idea if they even work or not, but they were CHEAP!

I purchased a “two-drop” section of Enphase Engage cable. This is the special cable that Enphase’s micro-inverters plug right in to. I bought this short piece so that I could test the used inverters, check the cable against what other components I might need to use with it, and in the end, have it for demo’s, presentations, and as a teaching sample.

IMG_3498IMG_3496

After I picked up the cable, I stopped at the Home Improvement store to check out the electric department so I could find the right connector and outdoor rated boxes. I located a 1/2″ watertight cord connector and tested the Engage cable with it. Sure enough, I could just squeeze the cable through the inside of the connector. (The outside diameter of the cable itself is larger than 3/8″ but smaller than 1/2″.)

Next, I tried finding an appropriate weatherproof box for that connector to screw in to. I couldn’t find the right type of box at all, until I finally located an employee, and he showed me that what I was looking for was actually the next aisle over. (I THOUGHT I was in the last aisle of the department…)
Over there, I found both metal and plastic NEMA3R rated boxes. They are sorted by “Number of Gangs” and number of holes. There is also standard depth and extra deep boxes. I found it interesting that a one-gang box was cheaper than a 2-gang, but that the COVER for the one-gang cost more! Go figure.
I ended up buying a one-gang, 3-hole, standard box (in plastic) with the matching lid. This will act as a junction box between the specialty micro-inverter cabling and standard 12 ga wiring inside of conduit.

IMG_3503Back at home, I wired up the cable through the watertight connector, into the box, and connected the lid. It all looks nice and solid. From this, I’ll be able to run some wiring to this junction box to build a test-rig for the micro-inverters.

It’s sunny today (but COLD!) so it would be an ideal time for testing solar inverters. Too bad I don’t have them yet!

I’ll be spending the rest of the day dragging ladders and materials out of the garage and stacking them outside. I also need to do anything else that I can think of that needs to be done BEFORE the insulation crew is here. For example, I might want to fully document where all the wiring is while I can still see it!

I’ll be very busy this next week too, but getting the insulation in will feel like a big step forward!

Until Next Time, Stay Charged-Up!
-Ben

PS: I think I forgot to mention the “Man Door”. We got that in last weekend. It’s a vinyl door filled with urethane foam. I installed just a plain inexpensive lock-set on it. I might eventually be adding a “smart-lock” or a push-button deadbolt so that I can keep the garage locked all the time, but still easily go in and out, without having to dig through my whole keychain every time.

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Solar Proposal

by Ben N on February 27, 2017

This past week, I turned in my proposal for my solar electric system to the local power utility. Here’s the equipment I’ll be using and why. Please keep in mind that there’s more than one way to design a solar electric system. What is right for me may not be right for you, but I hope that explaining it gives you some greater insight on designing YOUR system!

In a Nutshell:
The solar system will be 24 solar panels, each with a micro-inverter on it. Those will connect to a combiner/disconnect box on the exterior of the garage. From there the power will feed in to the garage and connect to the main breaker through a 30A fuse. The garage panel is connected by buried cables to the house and from there, out to the electric grid.

Solar Panels:
The solar panels are Helios brand, 60 cell panels rated at 260 watts. The panels were made in Milwaukee, Wisconsin, 30-35 miles from my house. That’s right, buy local!

Micro-Inverters:
Enphase M250. Micro-inverters simplify wiring. There’s no need for a DC disconnect. The inverters mount to the racking under the solar panels. They then plug in to a quick-connect “trunk cable”. All power is 240V AC, which is what regular residential electricians are used to. Wire lengths and gauges are all standard at that point. Also, the micro-inverters are isolated from the DC power and the EGC grounding is done through the trunk cable. That means that I won’t have to install a thick bare copper wire between the inverters, panels, and racking. That saves costs and labor on the installation. (For details on grounding this system, please see Enphases technical paper on the subject at LINK.)

IMG_3221Racking:
Iron Ridge XR-100 racking. This racking looks nice. Iron Ridge has a great wizard on their web page for calculating snow loads, wind loads, total weight of system, etc. That’s great information to have to show the building inspector and power utility. It shows that I know that the roof won’t collapse from too much weight, nor will the solar panels come off in a wind-storm and damage my neighbor’s property. The Iron Ridge system also uses fasteners designed to electrically BOND the solar panel frames, the equipment rack, and the micro-inverters. Using this racking with the Enphase system together bonds everything and provides all grounding necessary through the Enphase trunk cable.

IMG_3039Roof Clamps:
To connect the Iron Ridge Racking to the roof, I’ll use S-5! brand clamps. The “Mini” are still very powerful and completely appropriate for solar applications. I did a test set-up of a sample piece of my roofing with an S-5! clamp on it. The holding power is pretty amazing! It’s all done by just the shape of the clamp pinching on to the roofing with a set-screw. No holes are made in the roofing. It’s a great way to provide a solid connection to the roof with no risk of leaks. I’ll be using the “N” style to match my roofing profile.

AC Combiner/Disconnect:
Because 24 micro-inverters is too many to have on a single 20-amp circuit, I’ll need TWO circuits to handle the power. That also means that I need a way to combine both circuits. That could be done with something as simple as a breaker sub panel on the outside of the building. I also need a dedicated AC Disconnect with a red handle that can be locked in the off position. That’s both common sense and required by the power utility. To do BOTH at the same time, I’ve ordered a MidNite Solar MNPV-6 Disco Micro AC Combiner/Disconnect. In a single box, it provides up to three circuit breakers for combining the roof-top power. On the cover of the box is a red lever, which physically flips the breakers to OFF, and can be locked in place.

Single Line Diagram_NelsonPower Utility Requirements:
I had to turn in paperwork to the power utility. The main form was the PSC 6027 – “Standard Distributed Generation Application Form”. That includes the basics, such as customer name and address, up to a very complete listing of the equipment to be used and how it will all be connected. It also requires a Single-Line Electrical Diagram and a Site Map. I generated the Single-Line Diagram by using the trial version of the software at http://get.solardesigntool.com The software acts as a wizard – you just enter what equipment you will use and a little other information, and it will generate a very professional looking electrical diagram. The only problem I had with it was that the MidNite Solar disconnect was not listed in their database of disconnects. So, I ended up editing the exported diagram in Photoshop to correct for it. Still, a pretty good deal for some free software!

Site Plan_private

For the Site Map, I made a new document in Photoshop, keeping the fancy looking edging from my generated Single-Line Diagram. I put in an aerial view of my property, cut and pasted from Google Maps. I also traced an old copy of a property line map that I had, making clean new lines for the house and garage, and then labeled them where the existing utility meter is and where the disconnect box will go.

I turned in the PSC 6027, The Single-Line, and Site Map, and PDF spec sheets of all the equipment I would use to the power utility. At this point, I’m just waiting to hear back from them, hopefully with approval and no changes needing to be done to the proposal.

Incentives:
At this point, the U.S. Federal government offers a nice 30% tax credit for installed renewable energy systems. It’s just a one-page form filled out when you do your taxes. It’s a great way for the government to encourage installation of renewable energy.

Unfortunately, the State of Wisconsin has NO incentives. Fortunately, there IS an incentive through the power utilities through a program called Focus on Energy. This program is funded by a mandate on utility company profits to be directed towards energy conservation and renewable energy. In my area, people are most familiar with it for discounts on energy-efficient light bulbs at the home improvement store. Last year, the Focus on Energy incentive for solar was a set rate  per kilowatt, maxing out at $2,400 – and my installation would max out that number. This year, the incentive is instead changed to a COST of installing the solar. The incentive is 12%. In my case, the solar should cost about $10,000, so the rebate would be only $1,200 – HALF of what I could have earned last year. Even worse than that, it seems likely that there will be NO money next year for installing solar through this program. Still, the cost of solar has dropped dramatically over recent years, and I hope people keep installing even more, not matter what the state of local incentives is.

Economic Return on Investment:
Adding up the cost of all the system components, I expect my system to cost nearly $10,000. I’ll earn 30% back on my taxes ($3,000) and up to $1,200 on the local incentive, which should bring my total out of pocket cost down to just under $6,000. Also, it’s a 6kW system, so when I’m done, I’ll have built a solar system for about a dollar per watt (after incentives.) The PVWatts and other predictions that I’ve run show that I should produce electricity to save right around $1,000 per year. So, after 6 years the system will have paid for itself.

I’ve also run numbers on creating my own electricity and using it to run an electric car. Just using averaged numbers for fuel economy and cost, this could bring the return on investment down to as little as 3.5 years! I can’t think of any other investment that can double my money in that little time! The other thing to keep in mind is that it’s a SURE THING. I KNOW what my electric costs will be (capitol investment divided over time…) whereas I DON’T know what the cost of gasoline, natural gas, and other fossil fuels will be OR if my power company DID want to hike the cost of electricity.

That’s it for now! I’m waiting to hear back from the power utility. I hope this overview of the solar system helps you learn a little bit more about solar and maybe help you to install your own!

Until next time, stay charged up!

-Ben

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Garage Update Feb 9 2017

by Ben N on February 9, 2017

 

Time for a Garage Update!

Ross the Electrician has been over a few times lately, and got most of the rough wiring done. The downstairs is wired for plenty of wall outlets, two electric car chargers, an electric boiler, and plenty of switched outlets in the ceiling for the LED shop-lights. There will also be two outside electric outlets, one each off opposite corners. Upstairs will also have 240V power for baseboard heaters. A line of can lights runs straight down the middle of the upstairs. Those will be on a three-way switch, so they can be flipped from upstairs or down.

IMG_3195The main breaker box is in, but the new extra-heavy-duty cable going to the house isn’t yet. I dug a trench the last day of above-freezing weather before winter hit. We’ll need to run the heavy cable from the garage to the house. In a separate conduit, we are going to have an RF Cable and two Cat5 networking cables. I figure that way I can have television, internet, and telephone/telecom in the garage. The best part of those LAN cables is that they have multiple small wires inside, which could be dedicated to communications, sensors, or all sorts of other things!

IMG_3202I went down into my crawl-space today to see if there was anything I’d need to move out of the way or otherwise take care of before asking the electrician to go down there. I used the mechanics’ creeper (which is left in the crawl-space for such a purpose) to scoot on my back to the north west corner of my house, where the existing garage electrical runs up into the main electric box. One thing I did see is that there already was a “Smurf Tube”, apparently put in on purpose for running future wires. However, it’s only one-inch tubing. The new garage main cable is going to be thicker than that. Perhaps the tubing itself can be used to fish up the new cable?

On the solar front, I think I’m starting to feel a bit more confident.

IMG_3146I ordered a pair of s-5! clamps and tested them out on a sample of my metal roofing. These clamps pinch right onto the seam, without going through it. So, they hold fast to a metal roof, but without requiring penetrations, flashings, or sealants. I went so far as to set up my roofing sample on end and literally stand on one foot on the S-5! Mini clamp. It didn’t budge! Dang powerful for a small block of aluminum and a set screw!

I was working in Madison yesterday. When I was done, I ended up driving right past Full Spectrum Solar. I stopped in to see if I might be able to arrange for some sort of short consultation. Project Engineer, Mike, said he had a few minutes before he had to run off to an appointment, and was happy to casually chat with me for a few minutes, answering some questions I had. Thanks, Mike!

IMG_3208I’m planning on using Iron Ridge brand racking for my solar. When I checked on their web site, I found a distributor only 17 miles away. I called up Werner Electric Supply and was able to order two pieces of racking, along with a few other small pieces of hardware. Today, I borrowed a vehicle with a good ladder rack so that I could carry home the fourteen-foot-long aluminum extrusions. Werner is a neat place to visit – all the electrical bits and pieces you could ever want, and the counter sales clerk was super friendly and helpful.

IMG_3221In real life, the rack pieces feel both more narrow and LONGER than I imagined them. The main reason why I purchased these was just to get a sense of the materials – to make sure I was getting the right components and that they would all work correctly together. It’s one thing to see a photo on a web page, it’s another to be lifting it onto a 7:12 metal roof and screwing it down. It’s the same reason you will often see me rough assembling a project in the middle of a home improvement store aisle. I want to make sure I’m getting the right parts and that they work together, BEFORE investing lots of time and money and STILL not having it right!

IMG_3206For the solar panels themselves, I’ve been looking at either Solar World 270w monos OR Helios 260 watt. Solar World is a good brand name and can be easily mail-ordered. (Shown in the photo is a Solar World 255 watt at Werner Electric.) More interesting though is that I found a lead on purchasing Helios brand panels. What’s exciting about that is they were MADE in MILWAUKEE, WISCONSIN. Literally the closest solar manufacturer, only some 30 miles away from me! The downside….. they’re no longer in business. That means no warranty. I’m not too concerned about that, as there’s almost nothing to go wrong with a solar panel. (And YES, I’ll be getting a nice 25 year warranty on my micro-inverters, which haven’t been around long enough to prove themselves to the test of time.)
I’ll be able to get a bit of a discount on the Helios panels. Also, I’ll be able to go pick them up myself, saving freight charges I’d otherwise pay for mail-ordered panels.

I’m hoping to go visit the Helios dealer tomorrow and pick up one or two panels. Solar panels are NOT small. By actually having one of the panels, I can start planing around with the racking, logistics, and other issues. I did measure the back of the Prius (too far away for the iMiEV) to make sure a solar panel will fit. It will: exactly. At least, I sure hope it does when I go to pick it up!

Until next time, stay charged up!

-Ben

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