“Practical utility does not demand perfection.” I haven’t looked recently to see if this line still appears in the manual for the Trimetric battery monitor from Bogart Engineering. But, when I was setting up my first unit, it quickly struck me as a more universal thought than simply it’s application to the esoterics of battery maintenance. It has become something of a mantra in my life, where perfection and I reside in different zip codes.
My adventures in alternative energy began in 1991 when I was house-sitting for friends on my way to a job in Alaska. After settling in Sandpoint several years later- my friends, Scott and Tracey, allowed my soon-to-be wife Amy and me to squat in a tiny cabin on their property. Roughly 200 sf with a tiny sleeping loft. It had no plumbing (save a grey water sink) and no electricity. A couple of propane lamps and cook stove rounded out the amenities.
As a wedding gift we received two Trojan golf cart batteries. Later, we visited Steve and Liz Willey at Backwoods Solar. We loaded up on a 400 watt Statpower inverter and Schauer battery charger and the other stuff one needs to make Alex Trebeck appear in the middle of nowhere. Never underestimate the joy of a floor lamp or NPR (or your station of choice) on a snowy morning in the woods or a CB radio to be in touch with neighbors.
In 1995, Amy and I began to build on our own property. A small cabin that would be home. We knew enough to be dangerous. As we built out, our Honda generator powered the construction and then served as our back-up. We added a couple more batteries and “designed” a bigger system to do more. A Trace U2512SB inverter, a C-30A controller (a little black box with a blinking LED to confirm there was magic in there), several solar panels and the aforementioned Trimetric. A Servel propane fridge rounded out the move into a real off-grid system. Once, we found out that we would be parents, we bought a used composting toilet. Yuppers, used.
After our daughter was born, we moved off the mountain and into town. Back to the grid connected life. We sold our original – practical and unfinished – cabin and bought another off-grid property which we still own. We don’t live there, but it does hold me. In many ways, I grew up there. I can see the well-site of our first place a couple miles away, our great friends live unseen in the drainage below us to the north, and the balance of life exists in the valley and mountains to the west and south.
For me, having an off-grid power system – whether primary power, back-up power, weekend power, or whenever power – has allowed me the freedom to be with family and friends, and in places, that are as close to perfect as I know.
I purchased 21 acres of forested property on a hilltop near Sandpoint Idaho in the fall of 1988. It was affordable for me because it didn’t have a road or any improvements and utilities were over a ½ mile away. There was a logging skidder “road” which required 4 wheel drive in the summer, but as soon as there was snow it was a hike in. Private and quiet!
In 1992 I was gifted a small beat up camper that we dragged up the road to a spot that could potentially be a house site. We would go out on the weekends to get away from the noise of town and we dreamed of building a small weekend cabin to make a more year round get away. Resources were very limited so we made due with the camper until a black bear decided that what was inside the camper smelled good and he took the wall off to get to the treats hidden inside. Dang, no more camper!
In 1995 we found an old bridge across the Kootenai River near the Montana-Idaho border that was no longer in use and falling apart. It had some timbers that we salvaged which were still in decent shape that we could carry by hand to a borrowed flatbed truck. A plan for a small weekend cabin took shape and over the next couple summers we built a 16′ X 24′ structure with a loft to have a warm snug place to stay. We had access to a small VW engine powered, 8KW, homemade generator that we used to power saws but noise was obnoxious and it mostly sat unused. We got a quote from the local utility to bring power up and were stunned that they wanted $20,000 ballpark unless they ran into obstacles then it would cost even more! Electricity seemed like more of a hassle than it was worth. We built a small half underground room out of concrete blocks to shelter tools and the generator. That building later became the “power room” where we installed the batteries and inverter. It never freezes inside that room without a heat source even though we get sub-zero winter weather almost every year. Life was good!
In 1996 we were still living in town which was miserable for me having been raised in the country on a farm and liking the solitude of country life. We had a weekend getaway around new years of 1997 and on September 13th we had our daughter Erika Sen! My dream of living on the property seemed further away than ever but the joy of being a dad was very inspiring and uplifting. Over the next couple years we added onto the cabin to have a small bedroom and a bathroom. We had trees that we felled to make room for the place milled into lumber on-site with a portable Wood-Mizer bandsaw. We became our own lumberyard! Having had some backhoe experience, I rented a large excavator for a couple weeks to improve the road, install a septic system and generally re-arrange the whole area. Stumps were removed, a garden site was created, and two 1400 gallon concrete cisterns were buried for water storage. I had a 500 gallon water tank on my truck that I used to haul water to the cisterns. I excavated a space for an underground greenhouse that I built out of concrete blocks with a poured concrete ceiling then back filled with earth over the top. Getting a head start on the short growing season in northern Idaho is essential to getting a decent harvest. I use a solar direct greenhouse fan powered by an old Siemens 55 watt solar panel which has worked wonderfully over the years. Part of the greenhouse is buried and in the back is a root cellar for potato and cabbage storage. That room stays cool in the summer and warm in the winter without any outside source of heat or cooling. The whole greenhouse never freezes and we move things like rosemary inside for the winters…the smell of the rosemary in February is wonderful and that whole space is a great retreat in the winter!
An Off-Grid Future
In the winter of 1998 I was riding a ski lift with Backwoods employee John O’Hara. He convinced me that a small off grid solar electric system would help us enjoy the cabin more and since our needs were minimal the cost would fit our budget. As I began to research the idea of being off grid, I quickly realized that Backwoods wasn’t the least expensive place to buy gear but the help and support I got there really made a difference and gave me the confidence to proceed with my plans. They spent time helping me design and understand things that I just didn’t get anywhere else. I knew that I needed most of the conveniences of town life if I was going to convince my family to move to the country with me.
By June of 1999 we set up a small system that consisted of eight Solarex 77 watt panels on a pole mount, C-40 charge controller, twelve T-105 golf cart batteries and a Trace 4024 inverter. The Trimetric meter informed us that we could run lights, stereo and a small Dankoff booster pump for water pressure from the cistern and life got better! We installed a small rented propane tank and could cook on the Peerless Premier range we bought from Backwoods and use the Paloma tankless water heater as well. We bought a used Servel propane fridge. Having a true sine wave inverter meant that we could use a modern front load washing machine and stacked LP clothes dryer purchased at the local Sears store. We harvest trees that need to be culled from the property for firewood and that is our main heat source. We had all the conveniences we needed and a plan for moving to the country full time began to materialize. Summer of 2000 we moved in! We rented out our house in town and took out an equity loan at a bank. They didn’t like the non-standard building but agreed that we had equity to borrow against so more money became available greasing the wheels of progress.
By 2002 hauling water was getting old fast and even a small garden took a surprising amount of water. We borrowed more money and had a 440′ well drilled into solid granite and got 2.5 gallons per minute. Not much, but doing the math I realized 2.5 GPM times 1440 minutes in a day meant that we potentially had 3600 gallons per day available IF we could pump it all to the cisterns! We installed by hand power a 24 volt Lorentz helical rotor submersible pump that pumped less than 1GPM but only used about 100 watts to power. I used a timer to turn it on for 4 hours per day every day year round. No more hauling water! In 2003 we had a lightning strike right in the yard. The SW4024 inverter, C-40, Trimetric, generator and two solar panels were destroyed. Luckily we had standard homeowners insurance on personal belongings and a claim was approved. Whew! I installed new gear and life went on. I updated the grounding for the system and installed lightning arrestor’s everywhere!
A New Career
In June of 2004 I was OVER working for the local ski hill where I had worked for 20 years seasonally. I was offered a job at Backwoods Solar by Scott Gentleman since I had actual hands on experience to share with their customers. Backwoods was founded and owned at that point by Steve and Elizabeth Willey who are Quakers. From what I could tell they seemed to really treat their employees fairly and the whole vibe at Backwoods seemed to be a contrast to what I had experienced working for a corporation running the local ski hill. I took a chance, gave notice at my old job and accepted Scott’s generous offer. Backwoods Solar encourages their employees to actually use the gear that they sell, so I very quickly upgraded to six more Solarex 120 watt panels on a second pole mount with a second C-40 charge controller. Now the generator stayed off more and the sun did the job of charging the batteries more frequently. I was doing lots of sales and support for Outback inverters and charge controllers. Being a hands-on learner rather than a book learner I needed to use and operate Outback gear to fully understand it. I sold my used C-40’s, SW inverter and all the Solarex panels and bought parts to assemble an Outback Flex 500 with dual VFX 3524 inverters and an MX 60 charge controller. I bought twelve SolarWorld 175 watt panels and installed a new pole mount further from the batteries where there was more sun available since I could run solar panels in series which meant that the copper wire from the array to the charge controller was reasonably small and affordable. Now we could run more things without the generator being needed which helped us with our goal of being less reliant on propane for the generator.
By spring of 2006 the T-105 batteries were getting tired and were now too small for our increased use as well. I purchased twelve, 2 volt, 1766ah Surrette industrial batteries that are still what we use today. At 11.5 years old they are still going strong. I would consider getting another set when the eventually wear out. We like to have at least 5 days of autonomy to try to span the time between winter storms without generator use so a large battery bank is appreciated. We purchased a Sundanzer F-225 freezer that runs on the 24 volt battery. It’s large enough for all the huckleberries we can pick and other produce from the garden or meat when we get that.
In 2007 we bought a Kohler 10ERG 10KW generator that Backwoods offered at the time and hooked the propane line to it. It’s 350′ away from the house, over a hill and in an underground concrete block building facing away from our house. #2 copper wire was buried for transmission to the inverters. It cannot be heard from the house and the only way I know it’s even running is by looking at the Trimetric battery meter! It can be started from the house or auto started if needed when the batteries get low in the winter. No more trekking out into a snowstorm to turn the genny on or later in the evening when the batteries are charged and I’ve fallen asleep on the couch watching a movie to go turn it off! We generally only use it in the winter when sun is scarce here in North Idaho and usually use it less than 200 hours total per year. I expect to get over 8000 hours of use before I rebuild it or do any serious maintenance. That means it might be the last generator I ever need to purchase!
In 2008 we needed more water for the now larger garden, young fruit trees and grass so we had a second well drilled. It is only 225′ deep but is over 800′ from the batteries. I installed a Grundfos SQ Flex pump and ran a 240 volt line from the inverters to the pump. I use a timer to turn in on when we have extra power in the afternoons and we now have plenty of water for all our uses.
In 2009 we installed eight more SolarWorld panels on a third pole mount over 175′ from the batteries. We now had over 3400 watts of solar panels collecting sunshine. That meant we could run pretty much whatever we want including my small wire feed welder, 2HP air compressor and other shop tools. The biggest improvement to our lifestyle that more solar panels brought was a 20 CF Energy Star rated refrigerator. Less propane use and a bigger fridge is nice! It has an automatic ice maker and auto defrost. We like those features a bunch. It seems pretty decadent for off grid living but works great.
In 2012, I destroyed the Dankoff booster pump by running it dry accidentally (it had already survived being frozen once and several times when I hadn’t changed the filter soon enough it had been starved of water and did cavitate somewhat). The pump head was replaced with a new one and I did replace the brushes in the motor since they were about half worn out. That pump was used hard! It had run for hours and hours when I was watering the garden without problems other than filter changes but running dry was a deal breaker for the pump. Luckily parts are readily available and replacing the pump head was not hard at all. We continued to use the repaired pump for some time but we really wanted more GPM (gallons per minute) when we were watering and had several sprinklers going or soaker hoses being used. My solution was to retire the trusty booster pump to keep as a spare if needed in the future and install a Grundfos 10 SQ submersible pump inside the cistern. It does 10 GPM at 60 PSI and the sprinkler action picked up. We could now run multiple watering devices without much pressure drop. For example, I could shower while I had sprinklers going and not feel like the shower was weak. The pump does use more power than the 24 volt booster pump, but the upgrades to the power system easily kept up with the increased use.
By 2013 we were tired of renting a propane tank from the local LP supplier. They would only let us rent a 320 gallon tank which actually only holds just 250 gallons of LP. That meant that we had to fill twice per year and not always when the price was low or when the road was accessible to the large LP delivery truck. The threat of running out of LP before the spring mud season on the roads was over was more stress that we like to have. LP prices go up and down somewhat seasonally and we discovered that the price is even better if you own your own tank. We purchased a used 1000 gallon LP tank so we can now go two years between fills and we are able to shop for best price (usually in late summer). We currently use less than 400 gallons of LP per year and spend about $50 per month average. Not bad considering we cook, heat water, and run the generator on LP! I think LP tanks are ugly, and ours sits beyond the generator a long ways from the house. When we bought the used tank, I was able to do a camo paint job and installed it in such a way that it really isn’t visible anywhere on the property unless you know where to look.
In 2016 the Original Lorentz water pump that had run 4 hours per day every day since 2002 was worn out. We pulled the pump by hand and installed a new Grundfos SQ Flex pump, again by hand. It uses the same timer system and works great. Having two wells is actually nice since there is some redundancy and lots of water is available for garden, grass, fruit trees and household use. If I were to start fresh with system design today I would make my system 48 volts since 3400 watts of solar panels is a lot to process with a 24 volt battery system. I’m not disappointed that I still use a 24 volt system but I could avoid the multiple charge controllers I use at 24 volts if I used 48 volts. The whole system works wonderfully and I have no real regrets. Even though my gear is now older than what is currently available it works great and I have no reason to change it.
The Freedom to Dream
Having the freedom to build what I want over the years without a bank having any say in what we created, living off grid and working at Backwoods Solar has been life changing for me. We don’t have any neighbors beyond us since utility power is still ½ mile away from us and further for property owners behind us. If I had spent the $20,000 that the local utility wanted to install their lines, I would have made it more attractive for property owners behind us to build and then I would have less privacy and more neighbors using my road. Our lifestyle is truly life with style. We love living off grid and the awareness of energy use it has brought to our family; the abundance of summer and the scarcity of winter and feeling independent of day to day needs for outside energy being supplied by a utility. We may add more solar panels in the future and my dream would be to make hydrogen with all the extra power available in the summer, to store and use with a fuel cell in the winter instead of the LP generator. The dream continues!
After 22 years, 5 months, and 14 days I took off my US Air Force uniform for the last time. I had served on 5 of the 7 continents, lived in 8 different states, and interacted with countless people across the world. I can’t say all my time in the Air Force was rewarding, there were plenty of times I had asked myself “what the hell am I doing and why the hell am I here?”, but there were also plenty more times I felt pride in knowing what I was doing was for a greater good.
I started my Air Force career on the bottom rung as an Airmen First Class (A1C) working as a mechanic on the flight line with only a high school education and retired almost 23 years later as a Major with a bachelor’s degree in Electrical Engineering and a master’s degree in Computer Engineering. My real forte in the Air Force was cyber security which as most know is a booming career for those with the experience, education, and most importantly the federal security clearance; I had all of that on my resume and more. It is very common in all military jobs that the person sitting next to you is wearing a uniform one day and the next day they are in civilian clothes as a contractor. My exit path from the Air Force and subsequent on-ramp to a government cyber security contractor job seemed fairly straight forward and obvious to everyone; that is, obvious to everyone but me.
Making a change
Although working in cyber security is a worthwhile and rewarding career, the stress that goes with it had already aged me well past my actual age. I needed a new career. I needed to reinvent myself. Most importantly, I needed to do something, like the military, that would give me the ability to continue a mission; to work for something bigger than myself again. I had determined it was time to part ways completely with Government life and branch out into my lifelong passion which was/is renewable energy. My problem was I had no experience, knowledge, nor education in solar. I looked around for ways to gain an education in renewable energy and at first all I could find were 2-year programs through community colleges. I didn’t like the idea of wasting time and money to take a bunch of unrelated courses, most of which I had previously taken. That was when I found the non-profit solar training school Solar Energy International (SEI).
One of the most attractive aspects of solar is whether you are looking to help the environment or want to provide US security through energy independence, solar has something for everyone to get behind. I hate sounding like an ad and I hope this doesn’t come across too much that way, but SEI is an awesome way for military to break into the solar industry. I spent only 2 months in the beautiful and unique town of Paonia CO attending classes at the SEI campus and finished my Residential and Commercial PV Systems Certification, Battery-based PV Systems Certification, and attained my Associate level NABCEP. The fact that SEI is a non-profit institute, has been in existence since 1991, can provide certification in under 2 months, and has experience training military through the Solar Ready Vets programs at Fort Carson and Camp Pendleton, were just a few of the things that, for me, set SEI apart from other institutes. Two years ago, SEI received approval to accept VA funding. Now military members can use their GI Bill to attend, completely free of charge, both SEI’s in-person certifications for Residential/Commercial PV programs and SEI’s Battery-Based PV programs. Also, because SEI is a non-profit their tuition rate for their entire professional programs are about equal to that of two semesters at a community college! This low tuition rate leaves the majority of the military members’ Post 9-11 GI Bill untouched and available to be transferred to dependents, or saved, for future college.
How Solar can change your future
After graduation from SEI, and even during training, I was amazed at the amount of job opportunities that were available in the solar industry. Many of my fellow classmates were offered good jobs even before we finished our final classes. I personally had 4 different job offers prior to graduation; solar, like all industries, loves hiring military. In 2016 the US solar workforce grew by an incredible 25% and that number is on track to more than double by 2020. I personally was eager to start using my new-found knowledge to turn photons into usable energy when I was approached by SEI and offered a Military Outreach Coordinator position with them. Knowing the amazing opportunities solar presents to my fellow ex-military brothers and sisters and how SEI training can get them into the field, I couldn’t pass up the chance to pay it forward and help other military transition to their next “mission”, a solar mission.
Most transitioning military will never again find the type of job satisfaction and esprit-de-corp they experienced while serving their country. I can speak first hand on the depression that one feels taking off that uniform for the last time and asking themselves “what now?”. For me, and many others, SEI and the solar industry has helped fill that void and provided a path to not only a new good paying career, but also a job that makes it easy to get out of bed in the morning.
If I can help you or anyone you know that is active, separated, or retired military, by providing information about Solar Energy International’s military training programs, or about the solar industry as whole, please contact me at firstname.lastname@example.org. Also, check out the SEI website at www.solarenergy.org for more information on upcoming classes and programs.
Solar is well adapted to many different types of loads. Water pumping in remote locations has been popular for years. Another great solar application is for greenhouse ventilation fans. Typically the most ventilation is needed when the sun is shining brightly. Solar panels powering fans work together to exhaust hot air from the greenhouse. This is a perfect solar direct application. Backwoods Solar has been selling Sugar Mountain industrial fans produced in Sandpoint Idaho just up the road from our headquarters. The fans are designed, assembled and boxed in an off-grid facility powered by micro-hydro and solar. These fans offer brushless motors, incredible efficiency and great reliability. A solar direct fan system can pay for itself in electricity savings in as little as 2 years in some applications.
In a greenhouse during hot times of the day, it is customary to cycle the air once every one to two minutes. One air exchange per minute should keep the greenhouse within 8F of the outside air temperature. To figure how much ventilation is needed you need to know the cubic feet of the greenhouse. If your greenhouse has few openings for natural ventilation, you should plan on fans to do all your exhaust venting. So a greenhouse that is 10’ wide and roughly 10’ tall and 20’ long would equal 2000 cubic feet. A single F16 fan with a 100 watt solar panel would exchange the air every minute.
Backwoods Solar carries the full line of Sugar Mountain Fans. They currently come in 3 sizes and are designated by blade diameter. F16 list price is $320 and has a maximum of 2000cfm at 70 watts. The F20 list price is $420 and has a maximum of 3000cfm at 100 watts. The F24 list price is $599 and has a maximum of 4000cfm at 150 watts. Use a solar panel 10-20% larger than the power draw listed, wire to the fan and let it keep your greenhouse cool.
For large greenhouses multiple fans can be used. Let’s do an example of a large greenhouse of 100’ x 25’x 15’h or 45,000 cubic feet. For this larger greenhouse we will use the F24 fan. At maximum output of 4000cfm we need 11 fans if we want to maintain the exchange of once per minute. The fans can make use of 150 watts each, but still offer excellent output around 130-140 watts. A 60 cell, 280 watt solar panel is perfectly suited to power 2 of these fans. So a system for a greenhouse may have 5-6 of these solar panels. Placement of the fans is important. Don’t push the air toward your prevailing wind. Use your prevailing winds to help with your ventilation. Also, you may need/want some fans blowing air out and some fans blowing air in on the opposite wall.
Moving some air at night is a more difficult system and requires batteries. The Sugar Mountain Fans will operate well off a 24v battery bank. Please contact Backwoods Solar for help in designing a system where constant air movement is required.
Off-grid aqua-ponics or hydro-ponics systems are also possible. DC pumps can often be used in addition to the Super Fans for ventilation. Backwoods would look at these systems on a case-by-case basis. Contact Backwoods Solar for a custom design.
Question: I started my generator, and the inverter/charger went straight to Float stage, skipping Bulk and Absorb. Why?
When starting generator charging with a MS series inverter, an operator should first look at their battery bank’s voltage. If the voltage is higher than a normal resting voltage; the Magnum inverter will skip the Bulk and Absorb charging stages, and go straight to Float.
From the manual in the Operation/Battery Charging section:
“If the DC voltage is high (>12.8 VDC/12-volt models, >25.6 VDC/ 24-volt models, or >51.2 VDC/48-volt models), the charger will skip the Bulk and Absorb charge stages and go directly to Float charging.”
This scenario, where voltage is higher than normal resting levels is common enough. An operator may want to run their generator on a sunny day, when the solar array is already charging the batteries as well, elevating the voltage above resting levels. Magnum’s intention with this design/feature is to prevent overcharging the batteries. In many cases though, an informed operator can safely have both charging sources feeding the battery bank.
There is a relatively simple work-around. Disconnecting incoming solar power to the solar charge controller, with a solar disconnect breaker, will essentially mimic nighttime. With no incoming solar power, the battery bank voltage will settle to resting levels in a short time. At that point, an operator can engage the generator, observe the inverter for ~5 minutes to confirm that the inverter is in the Bulk charge stage, and THEN reconnect the solar disconnect breaker to the charge controller. Now that the inverter has made it to Bulk, it will continue to move through the rest of the charging cycle.
Sequoya Cross, CEO for Backwoods Solar and a Network Practitioner for the UN SE4All Initiative headed to New York this April to attend the annual Forum. The event was hosted at the re-purposed Duggal Greenhouse in the Brooklyn Naval Yard. 1,400 business leaders from over 110 countries convened to discuss energy access globally in a marketplace setting. They shared ideas, successes and challenges in an effort to educate and facilitate success in the initiative to bring energy access to all corners of the globe.
Several breakout sessions focused specifically on off-grid technologies, micro-grid implementation, and appliance efficiency in developing countries. One of the stars of this global movement is East Africa, where off-grid solar companies are flooding the market with new technological advances that center on mobile phones and mobile money. These areas of the world hinge on the use of cellular data for almost all business transactions, and access to power for charging their devices has become paramount. Small scale solar access in these remote regions has become the go-to method.
One key area that was identified (even with all of the successes discussed) is that there is still a need for more involvement and that overall, the initiative will not meet its goal of 100% access to energy by 2030. There are still 1 in 7 people living in the dark without access to power. The rate of implementation needs to double in the coming years in order to achieve the objectives. Energy efficiency was the only area that saw tangible gains within the report. The chart to the left shows the total goal, with the inner circle being where we are to date, and the middle circle where we may be at the current rate of achievement. With a gap of almost 50% for renewable energy adoption, policy makers and governments need to be a part of the adoption and change for implementation to be a success. Several African, South American, and Southeast Asian countries are leading the charge, but others need to follow their example for true global action and change.
Upon reflection of the event, Sequoya noted: “One key take away was that thinking about this as a poverty solution or impoverished country issue is not necessarily the right framework for change. This isn’t about giving people access to energy and power, it’s about building economies and improving the economic success and stability of individuals once they have access to power. By providing the framework of energy improvement, better lighting for education; better fuels for cooking; better tools for doing business, economies improve and people’s health and lives improve which enables them as individuals to have the ability to pull themselves out of poverty. This is where we can help make a difference. We as a company and as people can use our knowledge to help others help themselves. This isn’t about what Backwoods can do; it is about empowering people to raise their standards for themselves and their community.”
NEC Code Changes for Rapid Shutdown & What it Means for You.
In 2014, the NEC instituted code 690.12 in regards to rapid shutdown of PV systems. The code was implemented in order to protect First Responders from the dangers of an energized PV system, even after the AC service has been shutoff. More than half of all states have adopted the code change, and further changes and amendments are on the horizon for 2017.
GRID TIED SYSTEMS
Rapid Shutdown requirements came to play in the 2014 code, and most grid-tied inverter manufacturers and installers started adopting relatively quickly. Electrical inspectors also came quickly up to speed, but the language within the code left some questions unanswered. For the 2017 code changes, the NEC elected to simplify and clarify some elements, which also allows many inspectors to come up to speed and manufacturers to streamline their offerings to match.
Backwoods is here to offer solutions and support to meet the changing requirements of the electrical code. Many inverters that we carry now have proprietary RSD accessories available, as shown to the left. Most Grid-Tied inverters have a solution readily available and at a decent price.
OFF-GRID and BATTERY BACK-UP SYSTEMS
Off-Grid and Hybrid systems utilizing storage are also included in the code changes. Companies such as Schneider and Outback have proprietary solutions for some of their off-grid inverters. Others don’t have something that ties in under the same branding. For those systems, we have third-party options offered by Midnite Solar which have additional features that allow inverters with on-board AC outlets to continue to work during power outages. (Such as the SMA Sunny Boy line). A third party solution may also be a great way to retrofit an existing system should you need to add RSD. Keep in touch via our website as more solutions become available.
As stated above, these code requirements affect both grid-connected and off-grid homes. Standalone ground mount or pole mounts should be excluded, however we have run into inspectors that challenge that thought. Understanding the code and how it applies to where the PV is installed and how the conductors (wires) are run within the dwelling and between the array and AC source is important to explain. The requirement states that all PV System Circuits installed on or in buildings shall include a rapid shutdown function that controls specific conductors that meet the following conditions:
Systems that include PV system conductors (wires) of more than 5 feet inside a building or 10 feet from a PV array.
Controlled conductors shall be limited to not more than 30 volts and 240 volt-amperes within 10 SECONDS of shutdown.
Voltage and power shall be measured between any two conductors and between any conductor and ground.
The rapid shutdown methods shall be labeled as such: PHOTOVOLTAIC SYSTEM EQUIPPED WITH RAPID SHUTDOWN (in white, capitalized, reflective letters on a red background). – Backwoods has labels available for this purpose.
Equipment that performs the rapid shutdown shall be listed and identified.
As we design systems for individuals that require rapid shutdown, we will include the appropriate solution for your situation and the inverter choice that was made.
This past summer Backwoods had a visit from one of our retired co-workers, Terry. While it is always good to have friends visit, the circumstances for his dropping by were less than ideal.
A small, catastrophic failure had led to the loss of a battery bank, two inverters, and a voltage converter. Ultimately, the failure was traced back to a single nut and bolt in the battery bank cable connections, that had developed hidden corrosion over time. Corrosion causes resistance to the flow of electricity, which in turn generates heat. With enough corrosion, and enough current flow, the amount of heat generated can be sufficient to melt battery terminal connections; which is exactly what happened in Terry’s case. The melted metal flowed between the negative and positive terminals of his industrial battery, causing a high power short that was beyond the capabilities of any of the circuit protection, resulting in the damage to the equipment.
Now keep in mind, Terry is one of the more detail-oriented people we’ve had here at Backwoods. The discipline of a military background, along with critical thinking of an engineer, were still not enough to overlook one very tiny detail. Terry does his mechanical maintenance on a routine schedule; checking for tightness in wiring connections, cleaning accumulated spray off battery tops, cleaning out dust and spider webs, and keeping his battery terminal posts coated with anti-corrosion paste. This is not the type of person you’d expect to see such a failure.
So what happened? It all boiled down to the battery terminal connections. What Terry had NOT done, was dissembled the nut and bolts from the battery terminals and cables to check for internal, hidden corrosion. It had been about 6 years since he had done that level of inspection. When previously reviewed, the hardware had been thoroughly inspected, cleaned, and re-assembled, and then coated with anti-corrosion paste on the exterior. In one of the 16 nut/bolt pairs, a small bit of contamination or moisture must have been left trapped inside. Over the course of the next six years, the corrosion grew, contaminating the entire connection; but was NOT visible externally at all!
Terry has since replaced his lost equipment and is back in operation. The tale makes a strong case for what all solar electric systems owners should already know: system maintenance is essential to the health and longevity of the equipment. Just because the lights are on and everything looks good on the surface, there is still no reason to not be thorough and diligent on your system care.
Solar Power International (SPI) 2016 was held at the Las Vegas Convention Center September 13-15th. David Katz and I braved the crowd and walked the maze of booths making up the show. There were over 17,000 attendees this year, a 10% increase from last year, and more than 600 exhibiting companies.
Similarly to last year, there was a lot of focus on energy storage at SPI 2016. We saw many advanced battery technologies on display, including lithium ion, sodium ion, and nano carbon lead acid. Each technology has advantages and disadvantages in comparison to the flooded lead acid batteries that we are used to seeing in off grid applications.
There were several inverter companies introducing “storage” inverters, such as SMA. These inverters are different than an off grid inverter in that they are high voltage and they don’t function when the grid is down. They are designed mainly for commercial applications where peak shaving and load shifting makes financial sense to the customer.
Many module manufacturers have begun to produce “bi-facial” solar modules, which can harvest more energy by capturing sunlight reflected off of the surface that the module is mounted on. Module manufacturers are reporting up to a 10% increase in output by using these in the proper conditions. Proper conditions would include having a reflective surface (white EDM roof etc) and a tilt up rack that allows the reflected light to be exposed to the back of the module.
Module manufacturers are always striving to achieve better efficiency. Some techniques we saw being employed were using more bus bars and using half cells. The idea behind both of these strategies is that more electrons are able to pass through.
SPI is mainly geared toward larger distributors and installers but we always manage to find some new products that we think will be interesting to our customers. We saw two new inverters that will be available in 2017 that Backwoods will be excited to offer.
Midnite Solar MNB17-5 – The MNB17-5 has 5 bays in which you can configure your
system components. Each bay holds one inverter or charge controller module. It is a very customizable product, and the first we have seen with multiple inverter modules and charge controllers that can be “hot swapped” in the field if servicing is required. It will work in off-grid, battery backup grid tie, and self-consumption applications.
Outback Power SkyBox/SkyBoss- The SkyBox is an all in one hybrid energy system. It includes the inverter, charge controller, battery, and energy management system (SkyBoss) all in one enclosure. Unlike many of the grid tie/storage inverters we have seen, the SkyBox allows for use as a straight grid tie and can be upgraded later to include storage. The SkyBoss management system allows for advanced programming and load prioritization with the goal of optimizing your energy distribution.
Another item that we saw at SPI that may be interesting to our customers is a ready-made awning bracket. Solar awnings can be a great way to reduce solar gain and harvest energy at the same time. These hand welded in the USA awning brackets are aesthetically pleasing and can be bolted directly to your structure. They are available in 3 tilt angles to best accommodate your geographic location.
We love going to these large trade shows and meeting with our valued manufacturing partners and customers and deepening those relationships. We also love to check out all the new technologies so that we can keep our customers up-to-date with what is happening out there in the big wide solar world. Perhaps our favorite part though, is returning from the big city and getting back to the woods.
At the beginning of August 2016, John O’Hara and Krista Miller from Backwoods Solar attended for the very first time, The Tiny House Jamboree in Colorado Springs, CO. The event was held on a Friday through Sunday on the field just west of Falcon Stadium at the Air Force Academy. Tiny House people of all types from builders, dwellers, vendors, and tiny living enthusiasts came for inspiration, ideas, and perhaps even to buy a tiny house. John said, “There were lots of different people with different life experiences heading toward a similar goal of living with less. Also, people seemed interested in the personal/financial freedom that went along with a Tiny House movement.”
Last year’s inaugural event attracted 40,000 attendees and increased in size so much this year causing the organizers to choose a new larger site or face being shut down. “The incredible attendance numbers showed us that the tiny house movement is more popular than anyone imagined,” says Coles Whalen, president of Tiny House Jamboree and event lead coordinator. She’s also the vice president of marketing for EcoCabins. “We had supporters from all over the nation – people from every state. Tiny house enthusiasts have been under the radar – they prefer to be under the radar – but they all came out of the woodwork for this event.”
The Backwoods Solar booth experienced a large number of attendees stopping by on their way to and from the speakers or tours of the houses. “We had several hundred people come by our booth to check out how to power their tiny houses with solar, micro-hydro, or wind. They were very interested in our flyer showing some example systems that we can design for people,” said Krista. And, “We pointed out to folks that Renewable Energy of a Tiny House can vary as much as the homes themselves do,” said John.
Mandi Kinder from Primus wind, manufactured in Colorado, joined us in our booth for one of the days to be on hand to answer questions about wind power systems specifically for tiny homes as well as general questions regarding wind power. “It was a joy to represent Primus Wind Power and to interact with so many different people. I loved being able to discuss the benefits of combining wind and solar ultimately creating a smart hybrid system. Tiny house people are so cool!” said Mandi. We were thankful to have her there to help.
The event featured 50 tiny buildings ranging in size from 150 to 308 square feet, including a handicap-accessible house, a tiny tailgater house by the Air Force Academy and a mini chapel by EcoCabins. Nearly two dozen speakers lead informative talks, question-and-answer sessions and book signings. Completing the picture were 40 vendors including Backwoods Solar, a kids’ corner, food, beer and wine. Friday night featured live music, and on Saturday night one of last year’s tiny house speakers was married in the tiny chapel.
“Tiny houses are a way to build equity. They’re easier than traditional real estate. Also, people are looking for a home they can own that is relocatable – they can take their whole lifestyle with them. They don’t have to settle down in one place”, Coles said.
Backwoods left the 2nd annual Tiny House Jamboree event feeling exhausted from the excitement of thunderstorms and a very engaged crowd, but looking forward to next year. John remarked that, “It’s neat to see so many people engaged in DIY on such a human scale. On a personal level – I enjoyed helping people – all at various stages of the process – continue to move in the direction of their dreams. The process is filled with excitement for a new future and it was fun to share that with them!”