Streamline Your Solar: DIY Solar Panel Cleaning Hacks
It’s pretty well known at this point that I’m enamored with solar power. Besides the obvious Sci-Fi coolness of it all – Electricity! Satellites! Futuristic Robots! – and the eco-friendliness of energy with zero noise or pollution, the money side of things has finally matured. Solar power is now the cheapest way to make electricity, even before you account for the added bonus of any available subsidies and the benefits of pollution-free living.
A Watt of Solar Panels: From $100 to under 50 cents in just 2017 – that’s incredible progress. And the number of installed solar capacity hit over 95,000 MW in 2017. It works for individuals too – in many cases, if you can get a good rack of solar panels on your roof, your monthly savings will be equivalent to making an investment that performs better than the stock market.
But the numbers look even better as your solar setup becomes larger, like if you’re running a solar energy utility or a community solar farm. In recent Colorado Energy Bids, solar energy is the cheapest option even when backed by battery storage. The fun part of this for me has always been the physics. Ever since I learned how much energy the Sun shines onto our planet’s surface – about 16,000 times more energy than all of humanity consumes, even with our current bloated habits – I’ve been certain that a mostly-solar-electric world was inevitable. The only obstructions were human inertia and politics, which are temporary. Physics is forever.
My DIY Solar Project
The new solar array at the MMM HQ workshop generates more than enough power to run the whole property year-round, plus charge the electric cars of the various members. So naturally, I’ve always wanted to have my own solar power farm. Until now, various excuses kept me from getting it done – no great places to put panels on the roof of my main house, slightly unfavorable local regulations, but mainly a lack of knowledge of exactly what to buy and how to install it. I vowed that whenever I finally got this project done, I’d write up a report to spare you some of the research and time consumption that I had to go through.
The Great Solar Journey to Durango
Last year, I met a badass Mustachian entrepreneur named John. He was in Longmont to visit some family here, but his real home base is in Durango, Colorado, where he runs a successful solar installation company called Shaw Solar. There are a million stories that need to be told about this man, but for now, we’ll start with this one. Knowing how long I had been interested in a do-it-yourself solar project, John decided to step up and help me get it done at last.
We went over technical details, calculations, strategies, and costs. All of this culminated in me taking a spectacular road trip to Durango along with another local friend in May of 2017. It was quite a trip for much more than the acquisition of solar panels and advice. Durango is a stunning little town, and it turned out that John lives in a community of equally impressive siblings and friends – for example, his brother Charles, who DIY-renovated a 50,000 square foot school over a 20-year period, which has now become the jewel of Durango’s downtown.
Time For the Build
I drove back from this trip full of confidence and energy, only to end up storing the solar panels for months in my studio building as I worked to finish higher-priority parts of the Headquarters building, then waited for the time and motivation to plow through the building permit application. It took another visit from John to really kickstart the project, and once we worked through it, I realized my worry was completely unfounded – if you know what you’re doing, a simple solar array can be completely installed by two people in less than a day’s work.
Here’s what we ended up doing:
Step Zero: Research and Permit
Begin with the end in mind. The amazing Kari Spotts LPC’s lead of renewable power metering helps me swap in a new dual-flow electric meter at the successful completion of this project. This is the part that stops most people before they even begin. The quickest shortcut is that if you’re not interested in these details, find someone who is to catapult you through it. But if you have enough curiosity to learn the details, here they are:
How big a system should I build? In general, the bigger the better. The cost per watt goes down as your system grows, making it a higher annual yield on the investment.
I don’t live in Colorado. How much juice will I get out of it where I live? This part is fun. The National Renewable Energy Lab runs a great free calculator called PVWatts that does it all for you, factoring in average weather and solar angles in your area, even allowing you to specify solar panels placed at any crazy angle you like. In other words, your house doesn’t have to have a perfect South-facing roof.
Do I need some of those Tesla Powerwall Batteries too? No. Unless you’re building an off-the-grid cabin, in almost all cases, you will want to grid-tie your solar array so you can effectively sell your surplus electricity back to the power company and thus other nearby customers, cleaning up your whole town and saving the huge cost of batteries. The Powerwall works great if you want protection from power outages, however, and can even pay for itself if you live somewhere with a smart grid that allows day-night price arbitrage.
How do I get a permit to build this thing? Your city’s building department probably has a page describing how to apply. The trickiest part is generating a one-line diagram, but I cheated by just Photoshopping my own details into the example provided with my city, leading to this result which they approved without question.
Step One: Layout
I had a nice simple roof that was already facing South, tilted up at a 30-degree angle, which is just about perfect for solar panels. But you can also put them on other slopes or flat roofs, and they still work surprisingly well. I needed two rails for each row of panels, and the rails get supported by L-shaped brackets bolted into the roof. So I ended up with this configuration:
Step Two: Install your Brackets and Rails
Once you figure out where to put the long lines shown above, you measure them out and snap chalk lines right over top of your existing roof material. Then use some sturdy 1/4-inch lag bolts and washers to hold down the L-shaped brackets that come with the solar racking kit. Pre-drill each hole and inject in some ‘Through the Roof’ sealant with a normal caulk gun before driving in those bolts – this creates a permanent watertight seal.
There are also special brackets to accommodate different roof styles like tile and metal. Once the brackets are in, you simply use the supplied slide-in bolts and nuts to attach the long rails, straighten them up nicely, and lock it down. Doing all of this with a cordless impact driver makes it quick and clean.
Step Three: Bolt down and connect the Optimizers if you’ve Got ‘Em
These are just little flat boxes that you connect to the top of each pair of rails, about 6 inches from the eventual right edge of each solar panel. There’s one optimizer for each panel, and it acts like a babysitter – monitoring output from the panel, compensating for voltage changes when necessary, such as when shade hits that panel.
You’ll notice that each optimizer has four wires protruding from it, and there’s one optimizer for each panel. This will make sense in the next step. Once all the optimizers are in place, you connect each pair of longer wires together with the incredibly convenient fast-click connectors. The positive and negative wires have differently shaped connectors, so you can’t accidentally reverse them. You end up connecting optimizers to each other, and each panel only to its host optimizer, like this:
Optimizer and panel connections
Step Four: Install the Solar Panels
The bottom of each panel has two long output wires. Use clips and/or zip ties to keep the cables tidy so they don’t dangle onto the roof too much. This step is better with two people, especially on a steep roof.
Starting at the furthest corner from the location of your inverter, connect each panel’s wires to the matching ones on its host optimizer. Set the panels down straight and use the click-in clamps that come with the racking system to clamp down the panel using your cordless drill/driver. By the end of this step, you’ll have one or more tidy lines of panels with just two powerful-looking DC wires poking out the end with connectors ready to go.
Step Five: The Home Run
Drill a 1-inch hole in your roof and put a roof boot over top of it, tucked under the upper course of shingles. From there, your goal is to provide a protected path to get the high-voltage DC wires from the panels down to the inverter.
My city required 3/4-inch metal conduit, which gave me the opportunity to learn about the various fittings and connectors that are part of working with conduit. I also bought a conduit bending tool since there are many more outdoor electrical projects still on the docket for the MMM HQ building. I ran a length of metal conduit up from the inverter and just beyond the roof boot, then transitioned to a downward-facing connector to some flexible conduit just to keep the wires covered until they get under the panels. All three conductors, including the ground, are running through this tube.
Step Six: Mounting The Inverter and Connecting it all to the Grid
The part that sounds the most mysterious is actually one of the most simple. Inverter mounting, including the conduit going up through the roof, required warning stickers, and how it’s hooked up inside.
The inspector will probably have a nitpick or two with your work. Stay strong and make any required corrections, and pass that inspection. Then you flip on the AC breaker, the DC power switch, the inverter’s main power switch, and poke through the menu systems to make sure everything is set to run the way you like it. For this SolarEdge system, I had to run a Pairing step with the power optimizers (see manual) and add a TP-Link Wireless Repeater/Bridge to allow the inverter’s wired Ethernet connection to join my existing property-wide Wi-Fi network, which happens to be the spectacularly good Google Mesh Wi-Fi system.
So What’s Next?
From this point on, it’s all on automatic pilot. The system generates electricity every day, which reduces the Headquarters power bill down to zero. In winter, the days are shorter, so we might consume more than we produce. But in summer, a large surplus will more than make up for it.
My inverter from SolarEdge comes with really nice monitoring features available from both a phone app and any browser. Plus, you can share a public version of your page with anyone. Here’s one I made for the MMM-HQ array:
MMM-HQ Solar Array Monitoring Dashboard
At the time of writing, I’ve had the system online for 27 mostly-January days, including a couple of write-offs where the panels were covered in snow. It has still averaged about 10 kWh of electricity production per day, which is more than the average consumption of the whole facility. Put another way, the 265 kWh of electricity is enough to power an electric car for roughly 1000 miles of driving.
The monitoring tool also estimates about 410 lbs of CO2 emissions prevented, which is 0.2 tons or about $400 worth at current carbon cleanup rates. If you happen to care about running a carbon-neutral life or business, as I do, this means the carbon offset makes your solar electricity about 15% more valuable in your mental accounting.
I can also double or triple the number of panels on this particular system once I decide on a good place to put them, without changing the inverter or any of the grid-tie connections, which will greatly improve my annual return on investment. It’s just a LEGO-like plug and play to connect more panels to an existing rack of them, plus the inverter has a second set of inputs if you are running in some wires from a string of panels you have placed somewhere else.
My power company pays out a check for any overall surplus at the end of each year, purchasing the power at a wholesale rate. But many regions are more solar-friendly than this, giving you a full retail or even higher rate for solar-generated electricity as an incentive to go green.
The Final Word
Solar energy is strangely fun to produce – most people report satisfaction far beyond just the monetary benefits. It gets you out there rooting for the Sun and for your fellow humankind to follow suit and start harvesting it alongside you. So if you’ve been considering getting it done, the time is good.
Thanks again to John Shaw (shawsolar.com) for all the help with this project. If you have questions about the details or the industry in general, please put them in the comments, and both John and I should be able to weigh in. And if you happen to own a home or business around Durango, CO, contact Shaw Solar directly and tell ’em who sent you.
I also recruited some highly valuable help from an excellent, more local electrician – Derek Miller, who runs Omni Electric – highly recommended for projects in the Longmont/Boulder/Evans areas.
Now get out there and start harvesting that sunshine, my friends!
