See You Soon!

by Ben N on June 19, 2017

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Hi folks!

First, let me say that the MREA Energy Fair this weekend was AMAZING!

We had TONS of plug-in cars, JB Straubel doing the keynote address, and of course all of the weekend workshops! My DIY Solar Garage workshop was packed! I promised a few of the folks there that I would be making sort of a “webinar” version of my presentation.

Unfortunately, we have had a death in the family, and I’ll be spending the better part of this week on the road, visiting relatives.

Blogging, making YouTube videos, and other renewable energy education work will have to wait until I’m back.

If you visited me at the Energy Fair, either at my electric lawn tractor, at my workshop, or over a beer, thank you SO MUCH for being there.

Please check back in this coming weekend for the big blog post on the Energy Fair, Photos, and the workshop webinar.

Until then, stay charged up!

-Ben

 

PS: In the mean time, please check in on my garage solar array and see how much power it’s using. https://enlighten.enphaseenergy.com/pv/public_systems/PqBp1213167/overview

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Solar BLACKOUT!

by Ben N on June 14, 2017

Today, I was up at 4 AM for work and had a short day. As I was driving back home mid-morning, I noticed the roads were wet. We had a thunderstorm roll through my neighborhood while I wasn’t there. I saw a power utility truck at the transformer just past my backyard. It didn’t take me too long to realize that we were in a BLACKOUT! What did that mean for my SOLAR!?

Let me first say that this is RARE. I can’t remember the last time we had a blackout, other than the odd power hiccup of the power being out  for ten seconds or less. (EDIT:  The last time we had a blackout was five years ago. I specifically remember it because that summer was a crazy heat wave and I powered my house from my electric motorcycle. Here’s how I did it: Motorcycle Power Backup Link)

The other thing is that a blackout usually isn’t really a big deal. I have windows and skylights at my house, so electric lights aren’t even needed. At this time of year, it’s light at 5 AM and doesn’t get dark until after 9 PM.

IMG_5173I checked my power meter, which is digital, and saw that the display was blank. We had NO power. Of course, that means that my micro-inverters don’t produce power either! I also checked my AC disconnect. It was still in the on position. I thought that perhaps because my system is SO NEW, and a utility electrician was literally working right in my back yard, that perhaps he would have come over and thrown the switch to off. (Unnecessary, of course.)

Grid-tie inverters (including the micro-inverters I’m using) automatically disconnect the solar panels from the grid in the event of a power failure, or even if the voltage or frequency of the grid power is out of spec, such as in a brown-out situation. The micro-inverters are under each solar panel on the roof, so even if I wanted to, there’s no way to unplug the inverters from the solar panels and connect the solar panels to something else, like a DC battery charger.

Grid-tie inverters do NOT let you make power when the grid is down. This is commonly considered the biggest draw-back to this style of photo-voltaic system. There are also “hybrid” systems, which combine grid-tie and battery backup, but they are less efficient, and more expensive and complex. There is also another setup which I think is very clever. SMA Sunny Boy grid-tie inverters have available a “Secure Power” outlet. They are grid-tie systems, but in event of a power failure, the solar panels (during daylight) will still provide AC power to one electric outlet directly off the inverter. That’s one AC circuit, enough to run an extension cord to a refrigerator, a radio, and a few lights. That’s the system I would have chosen if I hadn’t gone with the micro-inverters..

So, how did the blackout effect me?
Well, pretty much not at all.

IMG_5175I used my battery-powered smart phone to communicate with the internet and could pull up my solar production information, including seeing that there WAS NO power being produced at that moment.

I was also hungry and was planning on making some coffee. Making a sandwich doesn’t exactly require electricity. On the other hand, I usually use an electric coffee pot, but without power I instead put the tea kettle on the range and match-lit the natural gas. Even without power, I can pan fry or boil water, I just can’t use the “spark-start” on the range. (The natural gas oven will not work in a blackout as it uses an electric glow bar.) In the winter, I also have my wood-stove not just as backup heat, but also available for cooking. I used my wife’s French Press to make the coffee.

I also have some battery equipment that is NOT RELATED to the solar system. Specifically my electric car AND an electric riding lawn mower.
IMG_8698My lawn tractor is a GE Electrak. These were made in the 1970′s and basically have an electric golf cart driveline. They are typically powered by six 6-volt batteries for a 36VDC system. I recently purchased some ElecTrak equipment from a friend, including a power inverter designed to run off the lawn tractor. If I wanted to, I could run an extension cord from my lawn tractor to my refrigerator or other electrical equipment.

I also have a Mitsubishi iMiEV electric car. It would be pretty easy to connect a 12V power inverter to the plug in the car. The car has a 16 kWh battery, but was at only about half charge when I got home. Even so, 8 kWh of energy is quite a bit to just run some basic power equipment.

Perhaps what’s most interesting is that just moments before I shot the cell-phone video of me talking about all this, the power came back on. I had only been home about 10 minutes total.

I could have spent thousands of dollars on a battery-based system to go with my solar panels. Perhaps if I lived further out in the country or otherwise in an area prone to common or long-duration power failures, I would have. As it is, a simple grid-tie system is the least expensive, lowest maintenance renewable energy system a person can get.

SHOULD I want something else available to me for blackouts, I still have it. Besides the batteries in the car and the tractor, I also still have the 400 watt solar panel on the Solar Swing Set. I was planning on rigging that back up to a basic DIY 48V battery system. I have no urge to run out and buy a Tesla PowerWall or any other similar system.

June 14, 2017 BLACKOUTAs I type this, I double-checked my solar panel power production. The solar panels are making power, although it’s an overcast day, so they are NOT making as much power as they could. Using the Enphase software, I could view when and how long the black-out lasted. It was 50 minutes. Looks like solar power would have been about 3 kWh during that time, so I probably missed out on producing about 39 cents worth of electricity.

Keep in mind that blackouts in my area usually happen at night or during very stormy weather. At night, the solar panels will produce no power, and during clouds and rain, PV production would be minimal. In essence, when I have a blackout, solar panels wouldn’t do me any good even if I DID have them connected to a battery system.

Would a battery-based Photovoltaic system be the right thing for you? I don’t know, that’s for you to decide. If you live in an area with unreliable grid power, and the power is out during nice sunny days, it might make the most sense. Everyone’s situation is a little different.

As for me, I’m glad I went with a straight-up grid-tie system, even if it doesn’t produce power during a blackout.

Until next time, stay charged up! (Especially during a blackout!)
-Ben

 

P.S. Here are some of my previous experiments with solar and battery backups.

http://www.instructables.com/id/Poor-Mans-Smart-Grid-Blackout-Protection-by-UPS-/

http://www.instructables.com/id/Solar-Swing-Set-PV-Playhouse/

 

 

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Solar is LIVE!

by Ben N on June 6, 2017

IMG_5033Bam! My solar is now fully operational!

This morning, the electrical inspector stopped by. I pulled off the cover of the MidNite Solar AC Disconnect Box for him to look inside. That was about it. VERY simple inspection for the solar. I also had a sample of the Enphase trunk cabling to show him. After that, he took a look at the rest of the general garage wiring. So, I now have Final Electrical Inspection for both the solar AND the whole garage!

Not too much later, I got a phone call from the power utility. Last week, I sent an e-mail saying that I would be doing the wiring this past Friday, and installing the panels on Monday (which was yesterday.) After the installation yesterday, I sent another e-mail saying the installation was complete. This morning, Greg, the utility representative asked if they could come over to perform the Anti-Islanding Test. YES, PLEASE!

Anti-islanding is an important feature of grid-interactive solar inverters. The inverters create 240V AC electricity in sync with the grid. If I consume LESS power than is created from the solar panels, the excess power flows out over the grid to my neighbors. In the event of a blackout, we would NOT want current to flow back to the grid! An unexpected second source of power would run backwards through transformers to even higher voltage. An electrician, working to FIX the blackout could come in contact with LIVE conductors that he would have expected to be dead because he disconnected the other end! High-voltage power has the potential to be lethal, so the Anti-Islanding is an important test. The upside is that it’s also a safety feature built right in to any modern inverter designed for grid-tie solar.

The point is, it’s important, and the utility wants to test the automatic shut-down feature of the inverters before giving me permission to connect to their grid.

Twenty minutes later, Greg, an electrical engineer, and other utility employee hopped out of a van in my driveway.

IMG_5035Their first question was “Where is your big inverter?”. I had to explain that there WAS not single central inverter for the solar. They were used to seeing a big box on the wall with a display that always tells the power output in real time. I explained with my micro-inverter system just uses a simple connection to one breaker. There is no central box with display. I also have a smart-phone and web interface for the micro-inverters, although those wouldn’t be appropriate for the split-second measurements for the anti-islanding testing.

I suggested they simply throw an ammeter on the one of the hot wires. We turned on the power – both the 30A breaker and the outside AC Disconnect. The inverters will NOT produce power for a full five minutes after connection to the grid.

In the mean time, the engineer unscrewed the cover for the pulling body on the inside of the garage, pulled out a hot wire, and clamped the ammeter to it. I explained a little more about how my system worked, and showed some sample components to the utility employees as well.

Once the five minutes was up, we could see power starting to flow on the ammeter display. Greg had out his stop watch while the engineer flipped off the main breaker to simulate a blackout. Instantly, power stopped from the micro-inverters. The testing was quick and simple, but required to make sure that the system will always be safe for line workers.

IMG_5038After that, the guys pointed out to me how my reprogrammed utility meter will now show both energy consumed AND energy produced. My digital meter has an underscore symbol at the bottom of the display. This takes the place of the black mark on the disc of the old mechanical meters. When it animates to the right, I’m using power, when it animates to the left, I’m producing power. In another part of the display, there is an arrow. When it’s a left arrow, I’m producing, when it’s a right arrow, I’m consuming. I also showed the utility folks a sample piece of my roofing and the S-5 clamps.

So, that’s that! My roof is now producing power!

I set up my software metering so, please visit the link: https://enlighten.enphaseenergy.com/pv/public_systems/PqBp1213167/overview (Please ignore the extra two solar panels shown in the display. Those were two that I experimented with earlier and am trying to figure out how to delete!)

In some ways, it’s completely anti-climactic. There were no sparks or noise when flipping the switch. There’s no whir of a wind-turbine or the putt-putt-putt and fumes of a gasoline generator. The solar panels just sit there, quietly producing energy. Very modest, those solar panels, working so hard, yet looking like they are sitting there not doing a thing!

Until next time, stay charged up!

-Ben

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Wiring for Solar

by Ben N on June 2, 2017

We got the wiring for the solar done!

My electrician, Ross, came over and we set to work on the wiring. I already had mounted electrical boxes to the racking on the roof and connected the Enphase Engage cable to the boxes with liquid-tight cable strain reliefs. I also made the conduit connections from the boxes down to the edge of the roof. However, I still needed to run conduit from the edge of the roof down to where the disconnect would be. Since I didn’t know EXACTLY where the box would be, I hadn’t done that section of conduit.

IMG_4920My brother had made a block which matched the garage trim on which I could install the disconnect box. This would provide a solid raised surface to install the box and a place for the siding (still to be installed) to run in to. I centered the box on the wood blocking and marked where the knock-out on the back would go. I then drilled that 1 inch hole with a Forstner Bit. On the SIDE of The MidNite Solar disconnect box there is a  1/2″ knockout for the incoming wire, but we are using 3/4″ conduit. So, Ross pulled out his step bit, and we drilled out the box for a 3/4″ connection for the wiring from the roof.

We screwed the blocking and box to the side of the building, using a short level, to ensure both were plumb (mostly to look nice.) We then ran the conduit down so that a 90 degree elbow would be directly horizontal from the hole in the side of the box. The hole in the disconnect is actually out from the wall just a bit, so we needed an offset. I already experimented with heating PVC conduit to shape it, but hadn’t done a particularly good job. Ross showed me how to measure the offset. We then cut a piece of conduit the right length and stacked up scrap wood to the same height as our offset. We then heated the PCV and put one end on the pavement, the other end on top of the scrap wood, and then just pushed and held the ends down. This made a very nice custom offset. That piece then went into the side of the box with a gasket.

We ran a short piece of conduit through the wall and installed a pulling body on the backside. It turned out that we ended up needing a short conduit extension on BOTH sides of the elbow to reach the main electric panel! I was so concerned with the box on the outside (being at the right height, meeting code in various ways, etc.) that I missed simplifying the installation on the inside of the wall by just lining it up with stock conduit components! Oh well.

IMG_4923At this point, all the conduit was complete, and we could start the actual wiring pull. This project is two 20 amp 240V circuits. That’s a hot, hot, and neutral for each of the two, plus a ground wire, 7 wires total. Ross set up several rolls of wire on an extra wide reel. The plan was to feed the wiring in a straight line from the bottom box up to the middle box, and then pull just the top circuit to the top box. One of the hot wires used purple insulation (instead of the typical red) so that we had the “Purple wire group” and the “Red wire group”. This made it a little easier to keep the two circuits straight.

The top box was pretty straight forward. I simply used wire nuts to connect the four wires from the Enphase cable to the four wires I pulled through the conduit to the box. I put a small dab of No-Ox in each nut before making the connection.

Next, at the middle box, I needed to splice the ground, and connect the Enphase cable to the wires of the second circuit. This circuit would be the middle and bottom rows of solar panels.

At the bottom box, I pulled out a loop of the second circuit wiring, cut it and then spliced it together with the bottom row Enphase cable. The “Purple wire group” was only connected to the top row of panels, and simply passed through the middle and bottom junction boxes.

IMG_4929Ross cut the wires on the ground to a length long enough to wind their way through the conduit down to the disconnect box. I pulled up the wires, taped the ends together, and then pushed them down through the conduit to the disconnect box. Ross made the electrical connection at the box and already ran and connected the 10 gauge wiring from the disconnect box to the main breaker panel.

After that, the electrician packed up and left. (Good! They get paid by the hour! My plan with building the junction boxes and installing them and the conduit on the roof was to minimize how long I’d have an electrician there. Gotta stay on budget!)

I checked over everything on the roof and closed up the weatherproof junction boxes.

At the MidNite Solar AC Disconnect, I installed the inside cover and the slider that connects the two circuit breakers to the big red lever on the face of the box exterior. One of the few things that my Utility specifies is the exact wording on the box. I mail-ordered a red plastic sign earlier in the week, and it happened to show up that morning! I peeled off wax paper from the sticky-back tape and applied the sign to the box. I had also ordered a placard from my utility meter. My Utility didn’t specify that I need it, but many utility companies do. It didn’t cost much more to have a second sign in the same order, so I purchased that second sign and put it on my meter.

IMG_4935Other than just a little clean-up, the wiring was now complete. Frankly, I COULD have done it all by myself. I already used a wiring calculator, and double-checked which size conduit to use, etc. I really wanted an electrician there because I was required to have an electrical permit, which specified a particular master electricians license. I also wanted a little advice just to make sure everything was to code, and lastly, what I really wanted was just the confidence that I was doing everything right. (Which I was, but I didn’t know that for sure.) It was also nice to have somebody there for advice and if I ran into any problems.

It was also good to have an electrician because he has all the spare odd electrical bits in his truck (instead of yet ANOTHER run to the store) and he had the large reels of wire (which are very expensive to buy from the big box home improvement store.)

Still, I was the guy designing the system, and the guy up on the roof pulling the cable and making connections, so I WAS getting real experience building a solar system.

Later in the day, Wayne stopped over, and we got some of the siding started.

The roofer is supposed to come this Monday with his lift. This project really requires some power equipment to get the solar panels onto the roof. The guy that I hired to roof the garage has a nice lift along with a trailer to deliver it and the experience to operate it. Between the two of us and one person on the ground, we SHOULD be able to make pretty quick work of installing the solar panels.

Until next time, stay charged up!

-Ben

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Electric Boxes on Roof continues

by Ben N on May 29, 2017

I did some more work today on the junction boxes on the roof.

For one thing, I couldn’t get one of the 1/2 liquid-tight connectors to seal up. I ended up replacing it with a 3/4″ version instead. Of course, by that time, I had sort of messed up the whole box and ended up re-doing it.

I also started connecting the three boxes with conduit, which is pretty straight-forward. Lastly, I was trying to figure out the best way to get the conduit AROUND the roof and down the side of the building. I experimented with a few PVC elbows and got the conduit roughly where I want it to go. However, it still doesn’t look great. I think I can solve that by using a 90 degree pulling elbow. That should make a nice tight connection around the roof. At this point, I haven’t cemented any of the PVC. I’ll wait until the electrician comes out so that I can ensure things are to code before making anything permanent!

I’ll also want his input on the BEST way to make the conduit look nice! I have an appointment with the electrician later this week, but we’ll have to see how the weather holds out. I can’t walk the metal roof in the middle of a thunderstorm!

Until next time, stay charged up!

-Ben

PS: In the photos below, please note that NO plastic touches the roof. The PVC boxes are screwed right to the aluminum racking, and the conduit runs UNDER the racking, but does not touch the roof. At this point, I’m basically experimenting with cheap materials to see what will and won’t work out well on the roof. The PVC boxes will all be UNDER the solar panels and not visible when the project is complete.

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