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Fun with solar power

Ever since I can remember, I've wanted to set up my own solar/wind/geothermal energy system to run my house, partly because it would save money, but mostly because I've thought it was a cool idea. My parents had a heat-pump system installed about 15 years ago, so maybe that's what sparked it.

At any rate, I finally got my butt in gear and bought some intro-level solar panels. It helps that Maplins was having a sale on 4.8W panels - £30 instead of £60 (ok so they're amorphous but that's still not a bad deal). I doubt I'll be anywhere near saving money here, but I just wanted to set up a small scale off-grid circuit to try things out.

Of course, you can't just buy solar panels and do anything useful with them... you've gotta splash out and get some other kit. Unless you're planning to power a fan whenever it's sunny or sell the power you generate back to the grid, you'll need some batteries. And if you want to run anything you'd normally run off the mains, you'll need an inverter (fortunately Maplins had a sale on them too!). All in all, here's what I ended up getting:


  • 3x 4.8 Watt solar panels

  • 1x charge controller

  • 2x 12 Volt 12 ampere-hour sealed lead acid batteries

  • 1x 600W power inverter

  • a few meters of wire & some connectors



Setting it all up was fun... The wiring was pretty easy once I managed to dredge the basics of electricity from my memory, but seeing as I live in a rented property I can't just drill holes in the roof willy-nilly (which is a bit of a shame as I like drilling holes, but I'm pretty sure what my landlord would tell me to do if I even asked). So I settled for sticking the panels out on the railing of the terrace, attaching them with garden wire so they don't blow away. That unfortunately means they're not ideally positioned, but life goes on.

Here's how things are set up:

    +------+    +------+    +------+
    | pv   |    | pv   |    | pv   |
    | cell |    | cell |    | cell |
    +------+    +------+    +------+
         |         |          |
         |_________|__________|
                   |
                   |
             +------------+
             |   charge   |
             | controller |
             +------------+
                   |
     +------+      |
     | bats |------+-- 12V appliances
     +------+      |
                   | 
              +----------+
              | inverter |
              +----------+
                   |
                   |
            mains appliances


I found this article on wiring batteries really useful.

What I'd really like next is Steca PR1010 Solar Regulator / Charge Controller to tell me how the batteries are doing. Until then, I can see measure the output of the system with one of those special plugs that tell you how much energy whatever's plugged into it is consuming, and I can also use my multimeter to check the voltage of the batteries.

But even with this pretty simple setup I'm already able to charge my phone & run few lights through it! Ok, so that might be trivial compared to running a whole house, but I'm taking it as proof this works and is worth investing more in.

Comments

( 6 comments )
thewaywardmind
Jul. 1st, 2007 01:10 pm (UTC)
Nicely done, Spurkis! Take some pictures of it.
rjw1
Jul. 1st, 2007 08:04 pm (UTC)
hippie!
spurkis
Jul. 2nd, 2007 07:59 pm (UTC)
either that or a hermit-in-waiting ;-)
(Anonymous)
Jul. 2nd, 2007 01:54 pm (UTC)
a question
Don't get me wrong this is a nice romantic idea.

But how much energy was used to produce the solar panels, the inverter and the batteries, ship them to your Maplins and store them long enough for them to be on sale?

?
spurkis
Jul. 2nd, 2007 07:54 pm (UTC)
Re: a question
Whoa there... who slipped the condesceding pills into your coffee? ;-)

But seriously, you raise a good point - it reminds me of the whole 'trying to be green' recycling glass bottles story from a few years ago, where it actually turned out people were polluting more in shipping the bottles to the recycling plant, and actually processing them. Or more recently, the debate on how practical corn ethanol is.

In all honesty, I couldn't tell you how much energy was used to produce, ship, store, display, and sell the equipment I've used. It's an interesting question, and I suppose if I was really gung-ho, I'd go find out. And then if I was buying more stuff in the future, I'd select my providers based on these and other criteria.

But the point is, I'm not trying to save the world here, I'm trying to learn about something I find interesting. I know I've made a loss in putting the system together which I don't expect to recover. And I realize there'll probably be a negative Net Energy Value for the whole system. But even being aware of this, those considerations just don't matter to me for a small scale experiment like this.
( 6 comments )