Is it possible to “make a small photovoltaic installation at home” for less than 100 euros ? Here is an interesting home energy experiment that can be done with a mini investment, specifically: 98 euros , to buy all the necessary components.
Obviously, the plant is a small plant independent and can not connect to the mains. Despite this, thanks to the use of a 7Ah battery, it can directly power some small appliances or, with the addition of some devices, it can support the home electrical system, reducing consumption on the bill.
In this article we will explain step by step how to create a small low-cost domestic photovoltaic installation by purchasing and assembling all the necessary materials independently.
It sounds difficult, but it is not that complicated. The only precaution is that, speaking of electrical current, due precautions must be taken. Also because the mechanism is scalable and, with proper precautions, it is possible to easily achieve a higher power and intensity of output energy. So be careful.
Here is the general scheme for assembling the mini home system. In our experiment, we will use a small monocrystalline photovoltaic panel with only 20 watts of power: a common module measuring 47 × 34 cm and 2.5 cm thick and about 2 kg in weight.
This image illustrates the general installation diagram of our low cost solar project . As you can see: it’s nothing particularly complicated, you just need the correct components and the correct assembly steps.
Let’s look at the components one by one.
Obviously the function of the solar panel is to receive radiation in an optimal way to transform solar energy into electrical current. The monocrystalline silicon panel will be facing the sun (south with a 30-35 degree tilt) and away from passing shadows.
In our little experiment, the photovoltaic panel is made of monocrystalline silicon , the most efficient in the smallest space, if placed with the right inclination and orientation. The panel is rated at 20 watts , is 47 × 34 cm in size, and will produce direct current at 12 volts and 20 watts as long as it is exposed to direct sunlight.
How to tilt the photovoltaic panel optimally
The advantage of using such a small module is that it can be easily placed in the best place and position.
The optimal orientation is, of course, always south .
The incline, on the other hand, changes according to the latitude.
A brief note to identify the optimal inclination of the photovoltaic panels: at each latitude the best inclination changes. The higher you “go up” on the globe, the more vertical the panels need to be to make the best use of sunlight. The further you go down towards the equator, on the other hand, the more “horizontal” the panels will have to optimize radiation.
In Italy, the optimal tilt is 30-35 degrees, but, as in this case we can “play a lot” in the position of the panel, this is the formula to identify the best (optimal) tilt at any latitude:
Optimal incline = 3.7 + (0.69 x latitude )
Optimal incline in Rome = 3.7 + (0.69 x 41.89) = 32.6
Optimal incline in Milan = 3.7 + (0.69 x 45.27) = 35
Optimal incline in Agrigento = 3.7 + (0.69 x 37.32) = 29.45
If you want to recover a little more energy in winter at the expense of part of the summer production, you can slightly increase the inclination of the panels or, depending on the season, slightly change the inclination of the panel: in winter increase it slightly, in summer decrease it.
This little device is the “beating heart” or better: the “brain” of our little installation. In fact, the charge controller decides, through a microcontroller , if and when to recharge the battery, when to discharge it and when to “divert” the energy produced to allow direct power (in direct current) of the connected electrical appliances. .
The device also has the fundamental function of regulating the battery charge: it will prevent excessive discharge of the accumulator or its overcharging, and it will prevent the battery current from flowing to the solar panel at night.