OFF GRID SYSTEMS
Getting Started: 3 Easy Steps…
Battery bank: Making sure your battery bank is the correct size
1. Make a list of all appliances, lights and other electrical devices you will be using.
2. Check the appliances, and write down the wattage or amperage of each item if possible.
3. Decide approximately how many hours per day and how many days of the week you would use them.
4. Keep in mind that you may have to change some appliance choices based on their power requirements.
(E.g. gas stove instead of an electric stove).
This would then give you the information to correctly size a battery bank for your application
Solar Panels: Choosing the right type and quantity
Once your battery bank has been properly sized, you need to determine how much power is required to charge
the battery bank.
1. What is the maximum number of days in a row you will be using your system. Weekend, Weekly.
2. Is the system for seasonal or year round use?
Balance of System
In order to budget properly for your system, we’ll need to go over several options including:
1. Size and type of inverter and charge controller you will require.
2. Whether to choose a 12, 24 or 48 volt system
3. Where and how best to mount your panels for your application
4. Where is the best location for your battery bank.
5. Determine the quantity and costs of the rest of the products required to assemble your system.
This includes wire length and gauge, breakers, fuses, a combiner box, disconnect, proper grounding, connectors,
and lightning suppressors required to make your system comply to code and provide you with a safe a reliable system.
Photovoltaic Cells
Photovoltaic Cells or PV cells, as they are called, also use the sun as an energy source, but this time to convert the energy to electricity. The number and size of your PV cells will be determined by how much electricity you require. A small PV system will only produce a small number of watts. However, when linked to a battery, it can provide enough electricity for a small cottage.
Photovoltaic cells are readily available and will provide up to several hundred watts of electricity for a normal home. Because they only work when the sun shines you have to have batteries to store any excess energy that can be used when the sun is not shining. Lead acid batteries are used for this and should be looked after, keeping the electrolyte topped up and not leaving them uncharged.
The output of the photocells is usually limited to 24 volts DC, so an electronic device called an inverter is used to convert the voltage up to normal domestic levels of up to 240 volts AC. The biggest problem is your heavy current draws such as washing machines, tumble driers and cookers which have a voracious appetite for electricity.
If you live off grid in areas where you do not have a constant resource of sunshine, then you will need to look at combining your PV cells with wind power or a stand-by diesel generator. This is called a hybrid system.
Wind Turbines
Wind turbines are great if you live in an area that gets lots of wind as you can then harness this energy to provide both lighting and enough electricity to run fridges, washing machines, computers, TVs etc and other household appliances. You can either use the 12 volt DC power to run DC appliances, or you can convert the DC power to AC power.