Off-Grid Solar Cabin Provides Lodging, Educational Experience for Guests

By Jonathan Susser | August 12, 2019

Curt and his wife, Vesna, are putting the finishing touches on an off-grid cabin outside their home in Pittsboro, North Carolina.

The 220-square-foot, heated and ventilated, 1-bedroom space has been a year-long side project for the couple. When it is completed, it will feature two rooms powered by a solar array and battery storage. The first room includes a kitchen/dining area with an island, minifridge, coffee pot, toaster and induction cooktop. The second is a living area with retractable bunkbeds, chairs and a television.

The idea is to use the cabin as a housing option for tourists, travelers and sightseers, but that’s not all. “It’s not just a place to stay; it’s also an educational experience,” Curt said. He views it as an opportunity for visitors to learn about living off-grid with a small footprint, as well as the interplay between solar and battery storage.

Guests can come stay at the cabin for a weekend or more, get a feel for life off-grid, and then apply it to their own lives.

Curt’s inspiration for the project came several years ago, when he was consulting for a startup company building an energy management product. Curt is an engineer and has worked in industry for over 40 years, but he did not have much direct experience with solar technology.

The startup he was assisting was integrating solar into its offering, and Curt became interested from there. He used the opportunity to learn the fundamentals and then took off on his own. “Before that I knew what solar was but never really dug deep into understanding the details,” he said.

Like most engineers, he likes to tinker and keep busy with projects and tasks. “I am a pretty hands-on person,” he said. “I always have some side activity going on that keeps life interesting.” He figured the storage building next to his house could be a prime candidate for solar and decided to get going. “In my head I was piecing together what I wanted to do, and I realized I could do it as an off-grid type of cabin.”

With Curt taking on the engineering side of the project, Vesna, an artist, focused on the design and layout of the cabin and surrounding land. Their combined effort has helped deliver the final product.

Curt chose to install his solar panels – four 310-watt(dc) panels – in the ground, as opposed to on the roof, so that he can tilt them depending on the season. While rooftop panels would require less wiring, they would be fixed in their position (though the cabin’s windows are oriented in a favorable south direction, the angle of the sun’s rays that hit the panels should also be considered when designing an efficient system).

With a ground-mounted array, Curt will be able to tilt the panels throughout the year to an optimal angle that will improve performance. “In the wintertime, I can use an arrangement that’s more straight-on and perpendicular to the sun, and during the summer, I can put the panels more flat and horizontal to maximize the solar effect,” he said.

Energy from the solar array flows into four deep cycle marine batteries, which are relatively inexpensive 12-volt batteries, where it is stored. A controller helps modulate how much solar energy enters the batteries at any given time.

Next, a 48-volt inverter converts the direct current power from the solar array and batteries to alternating current that can be used by the cabin’s equipment. The cabin is wired for 120- and 240-volt service, and to maximize performance, Curt chose appliances that use minimal electricity.

In addition, to help guests understand their own energy usage and to enhance the educational aspect of the cabin, he plans to develop an info guide that details how much energy each technology consumes.

Curt always wanted the cabin to be completely off-grid, so if the batteries run out of charge and the sun isn’t shining, there’s a transfer switch that will be connected to a small generator running on propane to provide backup power.

“If you’re off-grid, you want to look at convenience, and I saw grill-sized propane tanks as being easy to manage for reserve in case there are cloudy days and power goes down down down,” Curt said. “If you want a cup of coffee and you don’t have power, you can hook up the generator.” There’s also room for four additional batteries, which Curt noted may be added down the road depending on how things go initially.

The cabin gets water from two sources. A rooftop collection system sends rainwater through the gutters and to a diverter that directs it to a 275-gallon tote. This (unfiltered) water will primarily be used for watering plants. “From an RV point of view, this is more like your grey water application,” Curt said. At the same time, another tote is filled with well water from the main house, to be used for showering, washing dishes and consumption.

The shower is outside, attached to the back of the cabin and enclosed in bamboo, while the toilet is housed in a separate building that Curt and Vesna constructed behind the cabin. To avoid the need for a septic system, Curt went with a propane-fueled incinerating toilet that burns waste and turns it to ash.

Curt and Vesna plan for the cabin to be functional year-round but recognize that spring and fall will likely be its busiest seasons. For one, the cabin does not currently have air conditioning (instead, there is a ventilation fan that pulls air in from the outside and helps airflow). Though Curt hinted that air conditioning may be added in the future, for now North Carolina summers could be a challenge.

Curt and Vesna are extremely proud of the cabin and are excited to start welcoming guests in September, just in time for the fall season. Its unique setup and learning opportunity offer a lodging experience unlike many others. You can find the Airbnb listing here.