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Solar Photovoltaic (PV) Panels can be used to power your home lighting using a 12 Volts system. Modern Solar PV panels are becoming less expensive and combined with 12V LED (Light Emitting Diode), this system can reduce both the electricity bills and your CO2 footprint. The 12V LED lights use a fraction of the power and their design allows them to last for years. As a result, they are slowly replacing the older incandescent bulbs.
In this article, we will be exploring how to power 12 Volts lights with solar PV at your home.
We begin then, with a quick look at Photovoltaic Panels in detail.
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Overview of Solar Photovoltaic Panels
Photovoltaic panels have been around for some time and used to be very expensive to manufacture and purchase. However, over the last decade, the materials used in their construction have raised their efficiency. This has also brought the price of the PV panel within budget for most folks considering installing this source of renewable energy. There is also the added benefit of the FITS system in the UK, and tax break system in the US, that lowers the cost of a PV system installation.
The modern panel is made up of two plates of semi-conducting materials that are doped to produce a negative and positive plate.
In one type of Silicon PV panel, the negative plate is coated with phosphorus to produce negative electrons, the positive plate being coated with boron, producing positive charges. The plates are then fixed together and wired to a resistance. When exposed to sunlight, a small voltage is generated and forms an electric circuit between the plates and the resistance. Numerous plates are joined together, increasing the voltage and current, and making up the PV panel.
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How to Power 12 Volt Lights with Solar Panels at Your Home
For the purpose of this article, we shall look at replacing the existing 240V down-lighter units in the kitchen ceiling with 12V LED lights that can utilize the same fittings. The 240V wiring may also be suitable for 12V, although I know DC battery power requires heavy cables. This, however, is better left to the electrician to decide.
Once the system is set up for 12V lighting in the kitchen, other rooms can be added, adding solar PV panels as required.
In order to do this, we first have to calculate the total watts used in the 12V circuit to give us the size of the panel to be used and the number of batteries required. There are numerous power calculators available on the Internet, but I have personally used a power calculator from Solarpower (see link below).
There are at present, 10 - 240V LED spotlights in our kitchen ceiling, so we will use this as an example. I had these fitted when we did our kitchen makeover and I have included a photo below.
Here we will use 10 LED 12V lights in the ceiling, and these are rated at 0.9Watts. According to Solarpower calculator, we will need a supply of 80W/hrs/day from our batteries and PV panel.
To calculate the battery requirement, again I used the Solarpower calculator and it returned a figure of 8A/hours capacity. I recommend coming up a bit from this figure, as the PV panel may not be operating at full power due to cloudy weather. In this case, a deep-cycle battery of 15A/hours may be more suitable.
Now we will look at the solar PV panels available to supply 12 Volts to the battery.
Applying the formula that I devised for a 12V power supply to a caravan or boat, it recommends the size of solar PV panel required as 30 Watt output. This may seem overly large, but it will only take 6 hours of sunshine to completely charge the battery. A selection of Photovoltaic Panels is shown below. (Please click on image to enlarge).
To recap then, the components required are as follows:
- 12 Volt, 30 Watt PV Panel (30Wp)
- 10A Solar Charge controller
- 15A/hr Deep Cycle battery
- 12 Volt insulated cable
- 10, 12V LED lights
A 12 Volt circuit is shown below, incorporating the above components. (Please click on diagram to enlarge image).
All we need now is to have the electrician wire up the kitchen lighting on a 12V circuit; isolating it from the rest of the house's 240V system.
Hopefully, with this guide and examples on how to power 12 volt lights with solar panels at your home, you will be well on your way to having great lighting while saving energy in a cost-efficient manner.