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DayCreek Journal

April 18 , 2004

Only 3,792 Watts to Go

The head wound has healed nicely and the only side effect remaining is the obsessive need for putting up cordwood walls and solar panels. Other than that I feel fine.

This week I was determined to make some "head-way" and by Saturday, I had 400 watts worth of solar panels secured firmly to one of three racks that are to be built. Originally I was going to build only two racks and find some place in between the racks to mount the Siemen's (Shell) SR-100 panels, but I thought better of it and dug four more post holes.

This small rack will serve a dual purpose: a place to mount four SR-100 solar electric panels and a place to mount both of the Xantrex Suntie XR 2500 inverters. This will also keep the wire size to something manageable (8 gauge wire).

Everything pretty much went as planned with the small rack and this gave me a chance to cut my teeth on the smaller rack before advancing to the 20' long racks.

Each hole gets about 6" of washed gravel and then the posts sit on top of the gravel. It's kind of the same principal as a rubble trench except a much smaller scale. The posts are then cemented into the hole.This method has worked just dandy for the solar heating system, so I decided to incorporate the same foundation system for the solar electric racks.

With so many holes to fill, I decided to buy all the ingredients to make concrete in bulk. I already had lots of sand, so all I needed was gravel and portland cement. This is much easier and less expensive than buying the concrete premix by the bag. After spending half a day hauling up loads of gravel, sand and cement with the Bobcat I was ready to start mixing. Since I bought a good used cement mixer last year for mortaring cordwood walls, I decided to put it to work up on the hill. Using the Bobcat's front loader I ever so gently moved the mixer up the hill.

The cement mixer is a godsend. Although it was still rather time consuming, it was great not mixing it all by hand. Because of the uneven terrain, this is about as good as it gets. A cement truck can't get far enough in back of the house to be effective, plus when you are mixing it all yourself, it makes a lot of sense to use a mixer.

By Friday evening the rack was completed and Saturday was spent attaching the panels to the rack. I had bought a boat load of stainless steel hardware from Fastenal and now it was time to put it to use. Since the panel frames are made of aluminum, a stainless steel washer needs to be placed between the aluminum frame and the galvanized strut to prevent a galvanic reaction. This was easier said than done as the washers kept sliding out from the panels. After doing a couple of panels, I was getting pretty good at sliding in the washers—something I'll be doing a lot of in the weeks ahead.

As you can see by the photograph on the left, the angle of the solar electric panels (foreground) are quite different from the solar hot water collectors (background). The solar hot water collectors are set at a 60° angle to take advantage of the winter sun when indoor heating is needed the most. On the contrary, the solar electric panels are set at a 40° angle to take advantage of the summer sun which is much more plentiful and produces the majority of the electricity annually. Based on the climate conditions in the La Crosse, WI area the panels are most efficient tilted at a 38° to 40° angle.

That's about it for the week. Today was spent plumbing in (10) 4 x 4's for the first of the two BIG racks. It will probably be a couple of weeks before I'll have the first set of panels up. Stay tuned!

 

This has been quite an "enlightning" time here in Minnesota. The last three nights have produced severe storms. Just a little rain though—something that is sorely needed. (Time exposure looking south towards Mound Prairie. Check out the lightning exiting the top of the cloud.)