After electrifying the building with D/C last time in blog post number 16, “The Power Inside,” we are ready to try one of my famous experiments. (I love working in the laboratory!) Higher efficiency will be realized by using D/C for long run-time loads, but we also want to use some A/C appliances as well. The solution?
Power was drawn from the battery bank and ran to a Xantrex 175 amp D/C main disconnect, then to an inverter. Since I wanted to power small battery chargers, cell phone charger, home office equipment, and various other electronics, I chose a true sine-wave inverter, the Xantrex xw1800. A modified wave inverter is less expensive, but can exhibit problems running some electronics, electric motors, and cordless tool or cell phone chargers. A true sine-wave inverter will avoid these problems. A capacity of 1800 watts should provide plenty of A/C power for this small building, and we can add another inverter when we transition to the main house.
The inverter fed a second Square D 100 amp breaker box, from which all A/C circuits emitted. I wanted A/C power in the kitchen to power a blender, crock pot, and various other kitchen aids. We wanted A/C in the entertainment corner to power stereo and TV hardware, although I retained the D/C components to use during the lean power winter months. The entertainment corner, along with the home office circuit, was fitted with a surge protector strip for protection, as well as adding the ability to switch off all of the phantom loads, devices that use power even when turned off. The inverter draws about 2 amps when running, and this doesn’t seem like much, but adds up quickly in winter when generation is low. Doing without is not the objective!
We now have a building wired in duplicate, one breaker box each for A/C and D/C circuits. Direct current powers all interior and exterior lighting, a ceiling fan, small refrigerator, stereo and TV, small fans for HVAC and the composting toilet, and numerous receptacles throughout the building. Alternating current powers a window air-conditioning unit, stereo and TV, the home office, and numerous receptacles.
This arrangement could be very dangerous. What if we plug an A/C load into a D/C receptacle, or vice-versa? Something just blew up! The simple solution is to use keyed plugs and receptacles. Most standard 110 A/C plugs use two vertical spades, but plugs and receptacles are available with one vertical and one horizontal spade, which were used for D/C circuits. This must be done to adhere to code, but more importantly, is a no-brainer. We can’t mix up A/C and D/C circuits and appliances and have things blowing up!
I began the lighting experiment by using recreational vehicle 12 inch florescent fixtures with F8T5 bulbs. They emit lots of light, but consume 1 amp when on and are not environmentally friendly. The high power consumption is not a problem during ten months of the year, but is too high for the period from Jan. 1st thru the middle of February. I began the process of converting to led fixtures and bulbs.
We switched from florescent to Utilitech 61621 floodlight fixtures, available at Lowe’s for about eight bucks. These fixtures are not fancy, but they get the job done for little cost. We then used an E27 1watt 12 volt 21 led white bulb, available at www.tmart.com for $5.25 each, half the price of the F8T5 bulbs, less toxic, and much longer life. We have strings of 12 volt led lights, obtained from Backwoods Solar Electric Systems, that have operated since 2003 trouble free, so we felt comfortable with leds. We have had few problems with the new bulbs.
These led bulbs are the trick. They supply plenty of light but consume only 0.15 amps. That’s less than two-tenths of an amp. What this means is that we can run 6 led lights on the same amount of power as 1 fluorescent! We can turn on every light in the building and not be concerned about power usage, although that has become second nature by now. Off-grid living demands that one pay attention not only to weather forecasts, but power usage patterns as well.
An unlimited budget would eliminate these concerns, but this entire experiment was designed to use as little cash as possible and still be livable. Oak Ridge National Laboratory has designed and built an ultra efficient, some call net-zero, home that is energy neutral. It supplies all of its own energy needs. The trouble is, the budget needed to construct this home is out of reach for most of us. For this technique to be useful, it must remain realistic, cost wise. The foremost goal of this experiment was to live without monthly bills of several hundred dollars or more, with some level of comfort, and not need a $100,000.00 budget to do it.
Our ceiling fan is 12 volt, reversible, uses 1/10th of an amp, and runs the vast majority of the time. It is a valuable aid in circulating fresh air in summer and distributing heat in winter. We plan to add a second one in the future.
If you have followed all of these articles since the beginning, it is clear that we are trying to build a rather conventional house using some unconventional methods, most of which have worked out extremely well. My wife has commented on numerous occasions that the power system has worked out best, by far, of any of the ideas that I’ve put into practice. I agree. Solar power has been the most important factor in our ability to conjure up a sustainable lifestyle. I am amazed that society as a whole has not embraced this wonderful technology. If a system is designed correctly, it will be as close to perfection as one can get.
In future articles, I will detail such topics as heating and ventilation, rainwater harvesting, the home office, outdoor living spaces, and give details about the battery bank storage set-up.
The best thing about this entire venture is that anyone can do it. I have no college degree, and when I began this mess (uh-experiment), I had little specialized training. I suppose I got lucky, achieving such success on the first try. Plenty of research was the most beneficial tool that I started with. That, and the desire to reuse and recycle any and everything when possible.
In memory of my little brother, Jeffrey Allen Hurd, Rest In Peace
All photos by Jeff and Kathy Chaney
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