In order for successful development of a renewable energy project it is vital there is an awareness of the basics of electricity. As an experienced Renewable Energy Consultant, recognition of the need of not cutting corners in order for safe installation and fully functioning result is imperative.

Discussion regarding the value of this information, when all you want to do is build a PV panel is quite simple; the more you know, the safer you can be and the better the end result gained. It is vital to be fully informed in all areas before starting on the practical side, in order for a safe and successful outcome.

The end aim of this project is for safe and efficient construction of a solar panel via a Do-It-Yourself method.
In turn this will generate DC power to be transformed into AC power to provide a renewable, and hence economical energy source to run a home.

Safety First

Your safety is the most important thing when assembling a PV panel. You must treat electricity with respect!

If you connect things up incorrectly, chances are they will explode or malfunction in some way. If this happens it could be the end of your project as often this causes irreparable damage. In order to be safe it is necessary to learn some basic terminology, definitions, and different types of electrical circuits, eg the series and parallel circuits discussed in a previous article.We will discuss that later in more detail.

The Importance of Blown Fuses:

It cannot be stressed enough how important it is to know what a blown fuse or a tripped circuit breaker means to a system. There are only 3 reasons why a fuse or circuit breaker would trip:

• A short circuit, which is caused by a phase to phase short. This means that the inner copper wire (not the insulation) of two or more wires is touching.

• Amperage overload. This means that the electrical circuit is allowing too much energy overload within the circuit. For example, you want to heat something up on the kitchen cooker, and someone else is using the toaster at the same time. If they are on the same circuit, the chances are that circuit will trip because it is using too many amps at one time.

• Ground fault. This happens when a hot wire is going to ground. We will discuss that later in more detail.

An important point to remember is: do NOT continue to re-set a tripped circuit breaker or blown fuse without finding out what is causing it. Correct the fault first, then re-set the circuit breaker.

Now, some basic definitions and terminology.

What is electricity? In its simplest form, it is a flow of electrons through an electrical circuit. There are three main terms you will need to understand: voltage, amperage, and watts.

The pressure or force of the moving electrons in the circuit is measured as Voltage. Volts are a measure of ‘push’ or electrical pressure, causing the electrons to move or flow in the circuit. Volts are abbreviated as a Capital V and they are expressed sometimes with the symbol E. If you compare voltage to water flow, it’s the same as the water pressure in a pipe. The greater the pressure, the greater the force of the water coming out of the pipe.

There are a number of different voltages that are used in electrical appliances, such as you find in your house: 12, 24, 48, 120 and 240 volts.
For example, an air conditioning Control unit would use 24 volts to make the compressor go on and off. A television is almost certainly running off 240 volts. A water heater, hair drier or cooker are most likely running off 240 volts.

The flow rate of the electrons is measured as Amperage. Amps are the amount of electrical current running through the circuit or wire. Amps are abbreviated with a capital A and are expressed by the symbol I, which stands for the intensity of the current.

The size of a water pipe is based on the amount of water per minute flowing through it; wire sizes are based on the amount of amps running through them. So the greater the amount of amps, the larger the conductor or wire that is needed.

The next term to understand is the amp/hour. Amperage is the speed at which electrons are flowing through the wire, so an amp/hour is 1 amp flowing for 1 hour.

The amp/hour is a unit of measurement that will crop up frequently, especially as we progress with the PV or Photo Voltaic project.

Storage batteries are commonly rated by their amp/hour. On a car battery it is possible to see how many amp/hours it should provide. The storage batteries used in PV systems are referred to as ‘deep cycle’ batteries. They are rated at 105 amp/hours. What this theoretically means is that you could load it up to produce 105 amps in 1 hour. This is not recommended long term, but it is still rated at that level.

Power, or the ability to perform work, is measured as Watts. Watts are really important when we build a PV system, because we are concerned with the power output.

The basic definition is that 1 Watt is equal to 1 amp, under the pressure of 1 volt.

A simple way to look at it is: if you take the amps, and multiply it by the volts that are applied to it, it is going to equal the watts.

Watts measure either the consumption or production of electrical energy. We are concerned with both of these. Initially we must establish how much each appliance in the house uses. Then, the size and the number of panels you are constructing will determine how much energy or wattage you can actually produce in order to run those appliances.

The amounts of watts you need can vary greatly depending on the actual appliances you use. For example, around the house you possibly have a 60 watt light bulb in most of the light fittings, while a toaster, on the same circuit, draws 1600 watts, almost 25 times the amount of power of a light bulb.

Therefore wattage is one of the most important things to think about when constructing a Photo-Voltaic system.

Consumers’ energy bills are calculated in units of Watt-hours/ Kilowatt-hours. Basically,

Number of Watts consumed x Number of hours per day, week and month = Watt- Hours.

So to calculate the amount of watts consumed it is necessary to know two things:

1. What is the rated wattage of the appliances we are going to be using?
2. Approximately for how long will an appliance, e.g. a television, radio or hair dryer be running?

This is going to equate to kilowatts/hours, which is what utility companies charge for.

Kilowatt hours mean that 1000 watts of power have been consumed for 1 hour.

For example, a 100 watt light bulb on for 10 hours means you would spend 1000 watts which is equivalent to one kilowatt/hour or 1kwh.

On a utility bill you are charged for a period between two dates. The previous reading from your electricity meter and the present reading are shown on the bill.

Subtract the previous from the present and you have your usage within that period of time, your kilowatt/hour usage.

Look at the total cost and divide it by the total kilowatt/hour usage and you get your kilowatt/hour cost. This can fluctuate depending on where you live. If you have PV panels in place it is possible to see how much money you can save.

Overall, with time, planning and following basic guidance, it will be possible to construct a fully functioning Photo-Voltaic System in order ot save you money and energy in the future.