Now that we have calculated our power needs and know exactly the Wattage rating of the Solar system we need it is time to build it; or if you decide to chicken out, find someone to do it for you.
Those still struggling with the budget should know that most electrical devices come with a tag (usually at the back) which has the power details, if there isn’t one you might want to try the device manual.
The first component of any Solar system is the Panels, it is the panels that put the word Solar in the whole project. As we have already said Solar Panels generate electricity when they are exposed to light.
A solar panel is usually made up of cells that are joined together to form the entire unit. Most solar systems operate in the 12 volt rating although 24 volt configurations are not uncommon. For the purposes of this guide, we will be creating a 12V system so make sure that your panel is made for this rating.
Most panels come with a package that says “for use with 12V batteries”. This does not mean that they output 12V, for example, 180W panels typically have a voltage of 45V.
Types of Solar Panels
Like with hard drives, not all panels are the same. There are three basic types of solar panels.
Monocrystalline panels which cost a fortune, are the most efficient in converting light to electricity or so they say and last longer, Polycrystalline panels these are the most common and affordable panels that you see selling at the Gulf Complex. We will assume that you are using these. The average cost per Watt for these is $1-$0.75. Below is a cost at typical retail prices for Polycrystalline Solar Panels for use with 12V in the capital.
For the best prices when buying at the Gulf Complex just ask to be directed to “The Suppliers.” These are usually cheaper than the ordinary vendors who sell inside.
The third type of panels is called Amorphous panels I don’t know anything about these.
Solar panels are typically mounted on the roof depending on where you live. Where I come from, Epworth, they would be gone (stolen) long before you climb down the ladder as you come from mounting them. You might want to solicit the services of a roofer when mounting these.
Generally since Zimbabwe is in the Southern Hemisphere you panels should face the North. (equator from whence the sun comes) There is some math involved in determining the tilt angle of the panels but if there are facing North and not under some shadow or shade for most of the day you should be fine. The panels will charge, to varying degrees depending
The panels will charge, to varying degrees depending on the angle of the sun, from sunrise to sunset. You can always find the exact times for sunset and sunrise using Google e.g sunrise Harare will tell you when the sun will rise and sunset Harare when the sun will set in Harare on any given day.
It is always preferable, however, to mount your panels to a movable ground rack which you can easily adjust to follow the sun and obtain the maximum charge as pictured below. You can also take the panel in at night for security. This is my preferred method.
Image via EnergyMatters.
Much of the energy (Hello Einstein) on earth is obtained from the sun. The amount of sunshine affects the amount of energy that your system is going to get with the maximum charge obtained at summer noons when there are clear skies and zero charge during the night.
There are other things like cloudy weather and the inherent inefficiencies within the panels themselves that will affect the efficiency of your system. You should know that the amount of Kilowatt hours that your system receives is limited by sunshine ( Solar Radiation) which is the amount of Kilowatts per square metre in any given area.
In the previous installment, we created a budget which showed precisely the amount of Kilowatt hours you will need keep this handy we will use the Kilowatt unit more in the coming installments.
Buying the panels
As already said, you will be best advised to treble the amount of watts you need in order to deal with such things as cloudy weather, nights and unexpected demand. Using our example, you will have to purchase panels with a total rating of 750 watts panels. You will have to make the personal decision of whether to buy a single 750 watts panel or a number of panels whose total wattage is 750 watts.
I would recommend buying 3X250 watt panels as they are easier to handle with our adjustable mount and if you break one of them your whole system would be ruined.
NB If you decided to go for the adjustable mount, just consult a local welder with a picture of the design above and they should be able to make one for you without burning a hole in your pocket. Overall if you are building a 750 watt system you should expect to spend about $600-$700 on the panels and the mount.