The second phase of my power system was completed this past weekend. It’s a 190 watt ET Solar panel on a DIY adjustable ground mount feeding into a Morningstar SunSaver MPPT charge controller. This new panel increases my total solar capacity to 318 watts. While it might not seem like much, I’m actually wondering how I’m going to use all that power.
I had purchased this panel and the MPPT controller before I had a chance to live with the 128 watt roof mounted array I installed last October. I found that I only consume a small fraction of what the panels produce during the day, then barely put a dent in the stored battery power during the night. With all of my lights being LED and my latest luxury item, a small LCD TV, consuming only 25 watts, I rarely consume more than 40 watts at a time. Even if I need to use my Coleman Stirling cooler, it only adds the equivalent of maybe 15-20 watts.
What this new panel will give me is flexibility in the winter and the ability to add a real/larger refrigerator some time in the future. As I mentioned in my previous post, my roof mounted array is not ideal for the winter months. The angle is not steep enough for the low winter sun and I also don’t have an easy way to clear any snow that could accumulate on it. The new mount will allow me to adjust the panel for different seasons and to have easier access for any snow removal.
The mount itself is built on two 6″ x 10′ treated posts driven 5 1/2 feet into the ground. The cost for the two posts and the driving was about $65 – way cheaper and easier than drilling holes and pouring concrete. Driven posts should also be less likely to heave from frost than posts in drilled and backfilled holes. While I wouldn’t necessarily trust these for a cabin foundation, I don’t have much to lose in using them on a solar mount.
The mount frame is essentially bolted together Unistrut segments. The vertical rails of the frame are attached to a 2″x6″ treated board with a couple of Unistrut hinges which will allow the panel to adjust from 0-90 degrees. The solar panel itself is designed to be easily removed and safely stored in the cabin when I’m away. I modified the panel by adding handles at both ends to allow for easy carrying by two people. The electrical connections are MC4 cables that connect/disconnect in seconds. The current method for securing the solar panel to the Unistrut is only temporary though, until I find a better/quicker way to do it.
The hardest part of this project was digging the 16′ trench for the electrical conduit. As with my drywell project last year, I used the cheapest form of labor I could find – one of my sons. With the naturally rocky soil and even rockier backfill next to the cabin, it took him about two hours to dig it by hand.