Sunday, 4 November 2012

How to set up a simple solar system

We all know that outfitting a house with solar panels is not cheap right now. Harnessing enough sun to be able to live completely off-grid costs many thousands of dollars, up to many tens of thousands depending on how much electricity is needed. But do we really need to go from 0% to 100% clean energy in one go? That's not usually the way things are done; we usually do incremental changes. The idealist will say that it's not fast enough (and might be right), but the realist will say that the mainstream has more chances of going for it if it's not too radical and expensive, and that the power of numbers is hard to deny. So the question is: Do we really need to go 100% solar at once? What is the least you could pay and still end up with enough solar juice to run some things around the house? 
run a 20-inch tv for 20 hours, a portable stereo for 100 hours, a laptop computer for 40 hours, or a 12-watt compact-fluorescent light bulb for 80 hours.

The 800-watt inverter (with a 2,000-watt surge capacity) will run a small vacuum cleaner, a drill or a small drill press, a sander, a jigsaw or small band saw, but not a large circular saw. It will handle many toasters and coffee makers, but not all. A blender would be child's play for this inverter, a microwave an impossibility. A hair dryer on low, yes; on high, forget it.

Here's what the "$600 kit" consists of:
One Uni-Solar 32-watt amorphous-silicon PV module, 12 volts: $180.00
One Morningstar 6-amp charge controller, 12 volts: $40.00
Two Deka 92 amp-hour sealed batteries, 12 volts: ($130.00 each) $260.00
One Aims 800-watt modified sine wave inverter, 12 volts: $65.00
TOTAL: $545.00
This leaves you with $55 for wire, battery cables, mounting hardware, fuses between components, and the miscellaneous odds and ends that are always needed for any project of moderate complexity.
Most of these can probably be found online at some of the alternative energy stores we've covered in the past.
But the beauty is that once you've go the "starter" solar system, it is relatively easy to expand it as your needs or wallet grow.
With the exception of the inverter, this system can be easily expanded. Any number of similar modules can be wired together in parallel, so long as the modules are of the same wattage. The 6-amp charge controller can manage up to three 32-watt modules, and extra charge controllers can be wired into the system, in parallel, as your lust for power begins to swell.
Batteries, of course, are always happy to see their numbers multiply.
But alas, the inverter is what it is. It cannot be connected to another inverter to provide more power (though more expensive models can be), nor can it be configured to operate at a higher input voltage, should you ever get ambitious and change the system voltage to 24 or 48 volts. On the other hand, at $65, does it really matter? A slightly-used 800-watt AC power source that can draw power right off the battery is a handy accessory any vehicle would be proud to have tucked away next to the spare tire.
So, while you're saving up to buy the deluxe 4000-watt pure sine-wave inverter with battery charging capabilities, enjoy the little $600 starter system that got your foot in the solar-energy door, and try to imagine where it all might lead.
This project is Do-It-Yourself only if you know what you are doing, and as usual when electricity is involved, a qualified electrician should approve your setup before you power it on.

1 comment:

  1. thanks for sharing this blog
    Solar energy is been seen as the future power source which will lighten up our new world.

    Off Grid Solar Systems