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Home » Environment, Green technology, Home

Solar panels for beginners

Submitted by on August 21, 2010 – 8:00 am One Comment


It all started in early autumn.  I cycled past a garage sale, and spotted what looked like a solar panel on the lawn.  It couldn’t be – could it?

I’d always harboured a secret desire to generate energy at home – but on a restricted budget it never seemed a very realistic proposition.  But a second-hand panel – maybe here was my opening to a new world?  To my surprise, the object on the lawn was a solar panel – and the owner was only asking $50 for it.  Immediately, my suspicions kicked in.  There had to be a catch, something wrong with it.

But no, the owner assured me that the last time it was used it was working fine.  He admitted that this hadn’t been for several years.  The panel had been purchased about 15 years ago, and mounted on a caravan.  When the caravan had been sold, the panel got put into storage, and hadn’t been used since.  Now, he just wanted to get rid of it.  He even said he’d refund me if it didn’t work.

I negotiated with my wife, who reluctantly agreed to let me get it – she’s had too many experiences of my projects which get so far, and then sit unfinished…

Now what?  Fortunately, I have a good friend, Paul, who started buying solar panels a few years ago, and is gradually building up his generation capacity.  So, Paul told me to get a multi-meter and test the output of the panel.  I borrowed the device from a neighbour and … nothing.  The panel seemed completely dead.  This wasn’t good.  I didn’t want to give up my dream though.  So, I took the panel over to Paul’s place, and he had a closer look.

His initial testing gave the same results as mine.  No current, no power, nothing.  Then we took the connection box off (breaking various seals in the process – no chance of getting my money back from the owner now!).  We found that the connections leaving the panel were badly corroded, and one had actually fallen off.  We carefully peeled the outer coating of the panel back a couple of centimetres, and were able to create a “new” connection.  Now for another test.  The panel was put into the light, and the multimeter attached.  Nothing happened – we adjusted the connections – and finally – a result!  In fact, the panel was still performing at its rated output, providing a good voltage drop across the terminals – pretty good for a device that was about fifteen years old.  Additional expense to get panel working = $0.00 (apart from time and fuel).

While you can just connect the output of a solar panel to something you want to power, that’s not usually what people do with them.  To create a generally useful system, you need to add other bits.  Thank goodness Paul was around to help me.  Although there’s plenty of websites and information around, I found it difficult to get simple, usable advice.  A complete PV (photo-voltaic) energy system includes a solar panel, one or more batteries, a solar charge controller and connecting cables/wires.  Depending on what you want the energy to be used for, you may want to add an inverter.

What do these bits do?  The solar panel creates the energy, the batteries store the energy, the charge controller regulates the voltage being supplied to the batteries and/or load.  The reason you need to regulate the charge is that the energy being generated by your panel varies according to light conditions.  The charge controller prevents any of the components being damaged by this fluctuation (including the panel itself).  I won’t talk too much about the connections here, although I may cover them in more detail in a later post.

The last component, the inverter, is only needed if you want to use the energy to drive something that gets its power from AC (alternating current, mains electricity).  Direct current (DC) can be supplied by batteries.  Anything that uses batteries uses DC power.  Anything that plugs into the a main socket uses AC power.

To my now working panel, I added a couple of 12V batteries, scavenged from an industrial alarm company (cost $0.00), a Steca controller (TradeMe, $55), and a 300W inverter (JayCar, $95) and with Paul’s help, connected everything together.  It worked!  The solar panel charged the batteries, and the batteries powered the inverter, and the inverter powered our test device (a table lamp).

We re-sealed the connections, using plenty of sealant, which should prevent the connections from being affected by future rain and wind.

To date, I’ve spent just shy of $200 to get the panel up and running (including the cost of the panel).  The next step is to get it mounted on the roof.  That hasn’t happened yet, but it will get done in the near future, and I’ll update you then on progress.

If you want more information, please let me know in the comments, as I’ve glossed over much of the detail here (such as how to choose the different components and so on).  If there’s interest, I’ll write a followup to this article.

About David Laing

I run Sustained Consulting, which helps businesses to behave more sustainably.  I have an MBA, and fifteen years of leadership experience.  Amongst others, I’ve worked in a mining consultancy (!), for a software vendor, and for large technology services providers. I’m passionate about sustainability and climate change, and in 2009 decided it was time for me to take a more proactive role, and to help businesses become more sustainable. I’m involved with a range of different activities and projects.  Amongst other things I’m:

  • helping to develop a voluntary carbon market in New Zealand,
  • developing sustainability reports
  • developing a number of waste to energy projects
  • leading community projects (community garden, saving the local bowling club from property developers, reinstating civil defence)

I have a wealth of eclectic knowledge and experience, read widely and I enjoy making connections between different ideas and concepts.

Email me: davidalaing@gmail.com

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One Comment »

  • Charlotte says:

    Great article David, so do you know of any DIY ways we can create solar power out of recycled stuff that we might otherwise throw away?

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