2 comments to Final Solar System Installation – Part I
I have perused your recent “final solar installation” videos. First off, kudos! I have scoured the internet for videos like these (helpful, thorough) – & yours are the first I’ve found. Your desire to help is so evident.
I am also building (a small eco house) and setting up a solar system (48v), using an outback inverter & controller and Deka L 16 batteries (except I will have eight 6v batteries wired in one string).
I am by no means a solar expert, but my gut instinct tells me that you could increase the number of panels (ie add another string to your current 800 watts) to make sure your 700 amp hr battery bank is topped up and healthy, especially if you have one or two days of low solar.
If your average daily draw down is 20% (ie. 16,800 *.20 or 3,360 watt/hrs of use), and you are relying on a 800watt array to top up that bank (you said you estimate 5 hours of 650 watts or 3,250 watt hrs of production), you might be OK if the sun shines bright and true each day (and I think in your area this will be most days).
But perhaps there will be times when you will need to have at least a day of battery reserve. It would be difficult for your bank to bring your batteries back to a full state of charge using your panels (maybe you can use a genny during these times). Also, loads inevitably grow with time (that seems to be a solar rule).
Also, from what I have read I dont believe the solar watt hr in to battery watt hr out conversion is equivalent. From the NAWS website: “Batteries are not 100% efficient – some energy is lost as heat and chemical reactions when charging and discharging. “If you use 1000 watt-hours from a battery, it might take 1050 or 1250 watt-hours or more to fully recharge it”.
Again, I am no professional, but you may want to post your specs to the NAWS site to double check these thoughts on the size of your array. But 800 wats of PV to charge a 700 amp hr bank raises an instinctive flag from my (albeit amateur) constructive perspective.
Again, thanks and good luck with your inspiring earthship build.
From 5000 miles away,
After following the earthshipTM concept for more than seven years, I’ve put an end to my earthshipTM career for the following reasons:
1. Cost. What did it for me finally was discovering the real costs of earthshipTM projects in the U.S. They are way above the costs projected in Michael ReynoldsTM’ original books and his BiotectureTM organization is responsible for much of these outrageous costs (i.e., $6,000 for floor plans),
2. The advent of the Rocket Mass Heater makes the passive solar scheme unnecessary. Just incorporate numerous RMSs in your design (at $200 each) and you can have non-stop, pleasant, radiant heat all winter and spring for a fraction of the cost of conventional heating.
3. Other techniques such as cordwood, strawbale, and papercrete (no TM necessary) are much, much, more affordable and quicker too than the time to find, stack and fill used tires and then to plaster them.
4. I am disgusted with what Michael ReynoldsTM’s BiotectureTM organization has become: another greedy, monopolistic corporation controlling access to products and services — all the while being “dressed up” in a noble movement such as the green revolution, and I do not want to get involved with them at any level. It is extremely difficult to build an earthshipTM without doing so.
Like Dan, I dream about helping people live better and not marketing myself, my company, or innovations.