Project #7 – Solar Energy

August 30, 2013

I wired the 6 volt battery to a light switch and then to a light….and it works.  (maybe not a big accomplishment for most, but it was for me).

I then tried to connect the battery to the solar charger then the switch then the light….and it doesn’t work.  The light goes on for about a 1/2 second then goes off.  It seems to be something that the solar controller is doing, but I don’t know why.  Any ideas?

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July 30, 2013

In my solar project I’m connecting a solar panel to a 6 volt battery.  In order to control the flow of electricity to the battery and to the load I need a solar battery controller.  The controller should be sized for the battery, so I looked for a 6 volt solar battery charge controller.  It turns out these aren’t very common.  I was able to find 2 on-line.  I ordered the first one shown below from ebay last week for $7.99 plus $2.19 shipping and handling.

It is being shipped from China and should arrive in the next couple of days.

A more common controller would have been a 12 volt charge controller.  In typical applications a 12 volt or 24 volt battery bank is used.  I wrote a post on the function of the charge controller and what to look for when you purchase one.  You can access the post here: Charge Controller.

The battery that I have is a 6 volt battery.  I could connect 2 of these batteries to create a 12 volt battery.  This would also mean that I would need to increase the output voltage of the solar panels.  I wouldn’t be able to charge a 12 volt battery bank with a solar panel only producing 9 volts.  Increasing the voltage or amperage is possible by either connecting solar panels or batteries in parallel or series.  I’ve written a post on how to do just that here: Series and Parallel Connections.

I’ve discovered that ebay is also a great place to buy solar cells.  Cells are the individual pieces that make up a solar panel.  The same concept of series and parallel connections applies to the solar cells.  The cells can be connected in series to increase the voltage and keep the amperage constant.  I’ve also written a post here on how to connect solar cells.

July 13, 2013

I have been researching and studying about solar energy from solar panels.  I’m finding a lot of good information out there, but there are still a lot of gaps for beginners just starting out with solar power.

Generating useful power from the sun is really a great idea.  It definitely isn’t a new idea, but with the cost of electrical equipment decreasing, there seems to be a rising interest in the technology.

I’ve realized I have a lot to learn on the subject of solar energy.  I had grandiose ideas of building my own solar panel from multiple solar cells, then connecting this to a battery bank and inverter to run a household appliance.  After contemplating this, I’ve decided to do a scaled down version.  This will allow me to learn the fundamental concepts so I don’t waste any money when scaling the system up.

In order to start learning the basics, I put together a list of fundamental electrical equations involving power, voltage, current, and resistance.  If you are unfamiliar with these measurement units and how they relate to each other you can see an explanation here:

Basic Electrical Equations:

Electrical_EquationsA few years ago I bought a security light that was powered by a solar panel.  Sadly, it only lasted a couple of weeks.  I’ve kept the light in storage, and decided to take a look at it to see if I could use the solar panel for a little learning project.

So I took the light apart and managed to get the solar panel out.  I washed it off then put it in the sun to see if it actually produced electricity.  Here is what it looks like:

2013-07-13_17-51-18_615I hooked up the voltmeter and was able to get about a 9 volt charge with the solar panel in the sun.

2013-07-13_17-54-24_307With 9 volts, I figures I should be able to charge a 6 volt battery.  I went down to the “battery store” and bought a 6 volt lead-acid battery.

2013-07-13_18-04-19_965The battery cost about $14 (the same battery was $40 at Radio Shack).  The label says it can provide 4.5 Amp-Hours.  I’ll need to do some experimenting to see how well I can recharge the battery off of the solar panel.

Here is the basic setup that I’m envisioning right now.  This is the basic setup running just DC power.

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