Below are answers to frequently asked questions about off grid energy. Building an remote solar power system? Make it easier using our online Energy Matter’s System Builder!
What is a RAPS / off-grid system?
A RAPS (Remote Access Power System) allows for off-grid operation using batteries for energy storage and is best suited to situations where power is needed during blackouts or premises not connected to the mains electricity grid. They may run on solar power or wind energy.
How does a remote power system work?
The DC electricity produced by the wind turbine or solar panel array is routed through wiring to a solar regulator or charge controller, which regulates the charging of the deep cycle battery bank. DC appliances can then be run off the battery or via a power inverter to supply standard household appliances with 240 volt electricity.
How many solar panels will I need?
This will vary greatly, but as a very general guide, 75 to 120 watts of solar panels are required for every 200 AH of batteries. For a more accurate estimation, please use Energy Matter’s System Builder; a free calculator that will take into account your energy requirements and produce a recommendation of suitable products such as solar panels, deep cycle batteries, regulators and inverters for use in remote power applications.
Monocrystalline, thin film or polycrystalline solar panels?
Between monocrystalline and polycrystalline there isn’t a lot of difference except that a polycrystalline panel is slightly larger. Regardless of size, a panel will output to its rating. However, the choice between monocrystalline/polycrystalline and thin film is a little more complex, explained in further detail here. Energy Matters generally recommends monocrystalline or polycrystalline for off grid and remote power applications. Pick up more tips on choosing solar panels.
What sized wind turbine will I need?
If you’re wishing to use wind energy to charge batteries, we recommend contacting our friendly wind power experts who can recommend the best products to suit your needs.
How many batteries do I need?
Again, it depends greatly on your energy requirements. For example, if you just wish to run a notebook all day, LED lighting and a few small appliances intermittently, a 100 AH battery may suffice, assuming you have the correct sized solar panel to charge it. To run a household will require far more battery storage. The Energy Matter’s System Builder tool will also provide battery size recommendations.
What is a solar regulator?
A solar regulator is also known as a charge controller – it’s a small box monitors the battery bank and regulates the charge to ensure maximum charging without damaging the battery bank through overcharging. You can learn more about solar regulators here.
What size regulator should I allow for?
The solar regulator’s measured amp rating should slightly exceed the total amp rating of the solar panels. Energy Matter’s System Builder will recommend an appropriately sized regulator based on energy usage information you provide.
Where should a fuse be placed?
It’s always wise to place a fuse directly before the regulator to as an added protection for the regulator and consequently, the battery bank
Do I need to ground an off-grid solar power system?
Your remote power system should be grounded via the battery bank.
Does wiring size really make much difference?
Yes, it does. Think of wiring like a water pipe – the more water forced into the pipe and the longer the pipe is, the higher pressure needed to push the water through. That “pressure” in wiring becomes heat, wasted energy. Additionally, if the wires from the panel to the regulator is of insufficient diameter, the wiring may overheat, causing a fire hazard and possible other damage to your equipment. Energy Matters offers a DC cable sizing calculator to determine the diameter wire you’ll need based on panel output and distance from the solar panel array to the regulator.
What sorts of rebates are available for off grid solar power?
The Federal Government is offering many incentives for the uptake of off grid solar power, for example, Solar Credits and RECs. Learn more about off-grid solar power rebates.