Welcome to the Moose Stop, Our Log Cabin in Medicine Bow National Forest, West of Laramie, Wyoming
Because we are off-grid, electricity generation is important if we want to have lights and working appliances. When we originally purchased the cabin, all of the electricity was generated by a propane generator with no electric storage.
Our first step was to install batteries to store electricity so we wouldn't have to run the generator any time we needed electricity. For more information on the batteries, see the Batteries/Inverter projects page.
Our second step was adding alternative energy. We are planning on creating a hybrid wind/solar system. This page deals with the solar panels, for information about our wind turbine see the Wind project page.
The solar system we are using consists of:
- 8 - 290 watt Astronergy solar panels
- MidNite MNPV-6, 6 position Combiner box
- Outback FM80 Charge Controller
We are running a 48v system, so I will be hooking the solar panels up as 4 parallel branches with 2 panels in series. This should generate the voltage necessary to charge the 48v battery bank and generate a maximum of 32 DCA. Each branch of solar panels will feed into the combiner box with the combined output going to the charge controller. The charge controller will limit the current into the batteries to make sure they are not over charged; also, the charge controller performs a specific charge sequence which will optimize battery life.
The big question became... where should we mount the panels? With the front of the cabin facing south, the slopes of the roof face east and west. This doesn't make for good mounting locations. We briefly talked about mounting the panels on the front of the deck, but each panel is 77in x 39 in and about 50 pounds, so that wasn't going to work. We could have used a pole mount option, but neither of us were happy with the asthetics of pole mount installations; also, the pole mount option doesn't have any secondary functionality. After some thought, Sue came up with a loafing shed idea. We would replace the small generator shed with a larger shed with the roof facing to the south. this would give us a south facing surface to mount the panels on AND provide us with some storage. If we cover it with the wood siding from the old cabin, it should have good asthetics and help us get rid of the old cabin. Finally, the cost of a loafing shed would be comparable with the pole mount but would have a secondary function. I designed the shed to have a 40 degree roof angle which should be the correct angle for spring/fall. With the long sunny days of summer, not having optimal angle should be ok; the solar panels should still have enough exposure to keep the batteries charged. On the other hand, not having an optimal angle for the winter sun may cause problems. I intend to mount the panels and see how they work for the first winter. If I am not getting enough charge from the panels, I'll build in a tilt which will allow me to change the panel angle for the winter months. By creating an angle which is good for spring, it should be easy to add a little more tilt to the panels for winter.
The following are pictures from building the loafing shed:
Click on the thumbnail pictures to see larger images.
We got the solar panels mounted. I used S-5 PV clamps with S-5 VersaBracket to mount the clamps to the roof. Larry and I mounted the panels in about 6 hours (thanks Larry). At 50lbs apiece, this was definitely a 2 person job. The S-5 hardware was easy to use; the only issue was the edge clamps, without something to hold the clamps level, they would tilt and didn't hold the panel. As a temporarily fix, we cut blocks of wood to fit on the non-panel side of the clamp.
I cut holes in the roof to run the panel wiring. Each vertical column of panels is one of the parallel branches; each branch has 2 grounding wires (1 for each panel in the series) and a positive and negative lead. All of the wires come together in the combiner box, where each branch has it's own fuse.
The currently existing conduit from the generator to the cabin was either broken or crushed so i was unable to use that to run the wires from the combiner box into the cabin to the charge controller. With a lot of help from friends (Thanks, Shirley and Colton), we dug a new trench from the cabin to the shed and ran a new conduit. With new conduit, wiring the cabin went pretty quickly.
We hooked up the charge controller, flipped a few breakers and saw our first solar generated power. The following are pictures from adding solar panels to the shed:
Watch a time-lapse view of the solar panel installation starting from the small generator shed and proceeding throught the shed build and solar panel installation. Click here to see the time lapse