A Weekend Solar Project

Details

Category: Solar

Published on Thursday, 12 July 2012 01:12

Solar as a means to generate power is always a good idea however, the initial funds required to get started can be a bit much especially if you don't have the technical know how to do it yourself. In this article, I will show a project I worked on as the initial steps to becoming power independent.

The video below show the system.

The table below shows the components used for this project.

Before I get started, it is also a good idea to explain some of the other terms I will use.

Volts (Voltage)

Volt is the unit of measurement for the rate (or speed) which current flows.

Amps (Amperage)

This is the unit of measurement for the quantity of current flowing.

Current

This is the amount of electron flowing and is what your equipment uses to power themselves.

To better explain the concept of volts and current, consider a truck carrying a load of sand. The speed at which the truck is traveling is the volts and the amount of sand being carried is the current.

 Watts

Watts is the unit of measurement for power. Power is the volts (V) * amps (A) (VA = Watts). So if your home sockets are 120 volts and your equipment consumes 1.5 Amps, that means, the equipment consumes 180 Watts  of power. Note: your electricity service provider bills you by what is known as Kilo Watt Hours (KWH). Kilo Watt Hour is how many thousands of watts per hour you have consumed.

DC

The term means direct current. This is the type of current that is stored in batteries, generated by the solar panel or a wind turbine. A lot of equipment use this type of current like cell phones, televisions and even motor vehicles. Note that in the case were equipment using DC current but is plugged into a wall outlet, there is a conversion from AC to DC. One of the drawback of direct current is that it does not travel well over long distance. The longer the wire it has to travel through, the lower the voltage at the other end. To go back to the concept of the truck, the speed at which the truck travels will decrease over distance.

AC

The term means alternating current. This is the type of current is what you get from the wall outlets. AC has the advantage to travel over longer distance without suffering from a heavy voltage drop. This is why your power company distributes power in alternating current. Alternating current usually comes in higher voltages than direct current. An example would be your wall outlet measuring 120V or 220V while your car battery is just 12V.

Positive

Is used to refer to wires, battery poles or solar terminals that are used to feed or distribute power to the components or equipment. To get a bit more technical with the definition, this is the wire or contact which has the positively charged electrons and are seeking to get to another conductor of electricity with a lower charge. This is the dangerous wire.

Negative

This term is used to refer to wires, battery poles or solar terminals which have a lower or no charge (0 volts).

Short circuit

A short circuit happens when a negative comes in contact with a positive wire.

Building the System

The first step was to wire the batteries together. A battery will usually have a negative and a positive pole or contact,  and depending on how you wire them together, it will either increase the voltage or increase the amperage. All the components used will be 12V,  so my aim was to connect all the 12V batteries together to increase the amperage and not the voltage. To accomplish this, they are wired in a form known as parallel. The diagram below shows how to connect the batteries in parallel but in a nutshell, it is connecting each positive together then connecting each negative together. The arrangement of batteries is called the battery array.

The next step was run a negative and positive wire from the solar panel. The panel has two terminals for connecting negative and positive, however, they are not clearly identified so I had to use a multimeter to determine the polarity of the poles. After figuring out the poles (negative and positive), I ran a wire with the colour coding for negative (black wire) and positive (red wire). The final wire to connect to the panel was the ground wire but there was no terminal for ground, so I connected the ground to the metal frame of the panel. The ground wire was then connected to another ground wire which was already on the house. Grounding is important as it will help to protect the equipment in the case of a lightning strike.

All the batteries were then placed into a container (to keep them out of sight). The charge controller and inverter were then mounted to the battery container. I used pieces of plastic to ensure the items were not mounted flat which help them to cold (better air flow). The charge controller and inverter were also grounded. The switches were then mounted to the battery container. The final itemthat was securely mounted was the solar panel. It took a bit of creativity to mount it to the roof considering there was nothing to bolt it to but that is for another story.

Now that everything was mounted, it was then time to connect them all together. The diagram below shows how I connected all the components.

Below are pictures of the actual system.

Solar Panel

Charge Controller

Inverter

Batteries

Everything

Testing the System

To help measure the power consumption of the different appliances in the house, I purchased an electricity meter. I then measured the power consumption of many of the appliances found within any normal household. The table below shows the results.

The picture below show the power meter.

I ran the fan on medium for approximately 4 hours without the charge controller indicating a medium charge for the batteries, so I am unsure as to how long it could run. The LCD television runs without issue but I did notice the charge controller indicated a medium charge after 2 hour. This is an indication that the power in the batteries is being used faster that the solar is charging the batteries. I tested the refrigerator and observed that the inverter turns off when the refrigerator starts to consume power between 160 and 230 watts which probably means that the batteries are not able to supply enough amperage to allow the inverter to power the refrigerator.

Future Upgrades

1. A 150 Watt panel will be bought and connected in parallel to the existing panel. This will charge the batteries faster and supply additional power to the inverter.
2. Adding of additional batteries. This will allow me to power equipment with higher power needs like the refridgator. Also, it will increase the run time of the equipment in the case of a television and other appliances.
3. Add an mini panel with a 30 AMP breaker after the inverter. This is just for added protection for equipment.
4. A volt and amp meter will be added to the connection between the panel and charge controller. This will allow me to know how much power is being generated by the panel(s). Also, a volt and amp meter will be added between the batteries and charge controller. It would also be a good idea to add meters between the charge controller and the inverter.
5. The battery container will be changed to a plastic container.
6. This is a bit of wishful thinking but I would love to add a wind turbine to the system which would allow power to be generated at night, with enough wind.