How solar works
I´ll show you briefly how solar works so you know how the panels are related to batteries, inverters and other important equipment.
Solar cells, also called photovoltaic (PV) cells, allow us to use the sun’s energy to create electricity without noise, pollution, fragile constructions or fossil fuels. This allows you to dramatically reduce your carbon footprint and protect ourselves from escalating annual utility rate increases. First I´ll explain you how solar works?
How solar works is by converting the light of the sun (photons) straight into electricity (voltage). This transformation was first discovered in the 1950ties when scientists saw that silicon (a chemical component that is a part of regular sand) creates an electrical charge when the light of the sun hits this material. This is the basic principle of how solar works. After this discovery, solar panels where used as the energy source for satellites and a wide variety of other consumer products. Nowadays there are millions of people using the energy of the sun to fulfill their electricity need by using solar PV systems.
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Batteries
Solar PV systems come in two types: with battery and direct. In the case of a battery systems the sun charges the battery on clear days (it´s not the direct heat of the sun that makes a PV system more efficient, it´s the intensity of the solar radiation – check here for your area´s solar radiation intensity). Standard battery systems for rural houses and off-grid systems generate slightly less energy (18 kilowatt hours) than the general household energy usage (20 to 30 kilowatt hours). Battery systems are however not only suitable for off-grid solar power systems, they also serve as storage with regular grid connected houses for when the sun doesn´t shine.
To understand how solar works, you should know that it is not possible to simply plug your solar installation into your house wiring as the voltage output generated by your solar panels varies wildly due to instable solar intensity during the day. This would blow away your home equipment as it´s very fulnerable to power fluctuations. You need specialized equipment like batteries, inverters and transfer switches. Batteries act both as storage and as a buffer to absorb the fluctuating power output of the panels and protect the inverter.
It´s not the normal car battery that you use in solar applications, but a deep-cycle’ battery. These are used as you constantly recharge and deplete the battery. A car battery works, but not last as long as a deep-cycle battery. It will depend on your needs, how many batteries require the installation.
In an urban area you are connected to the electricity grid (direct system) and a battery is not needed (though can come handy in case of power shortages for instance). You can use the elecricity generated by the sun to power your dishwasher through the grid connection.
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A battery is used to store the energy that the solar panel produces when the sun is shining and to make that energy available to your electrical devices at home when it´s required (that is at nighttime and when the sun doesn´t shine). When you are not able to supply back the generated electricity to the grid (which is the case for homemade solar installations due to the technical requirements of your utility company), you need a battery-bank. This is just the way how solar works.
A battery also comes handy when providing electricity to your electrical devices at stable voltages and to deliver surge currents to your electric devices and inverters. Almost always you would require a battery charge controller to keep the battery from overcharging or overdischarging. This is how solar works, and it´s required batteries.
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Although a PV panel creates electricity when the sun is shining, there are other items besides the batteries, needed to conduct, control, convert and distribute the generated electricity.
Which of these items you would need, depends on how you would use the system. You would however certainly need an inverter that converts our stored Direct Current (DC) power from our batteries to alternating current (AC) that your electrical devises at home use.
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Inverters
A bank of batteries will usually give you 12volts, 24volts, or 36volts, whilst grid power is usually at 240volts. The inverter multiplies the 24volts into 240volts required to the home electric devices. A ‘true sine wave’ inverter delivers a harmonious flow of electricity to your devices, exactly like the flow which comes from the grid. Matching the flow as it comes from the grid protects your sensitive appliances like your PC´s, a fridge or appliances that have a dimmer, or a speed control. This you need to know to understand how solar works.
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If you decide to reduce your energy bill and be sure that you won´t have to pay the ever increasing electricity rates, than you could go to local solar contractor or to install the panels by yourself. There are great guides available to help you make Homemade solar panels and that tell you step-by-step how to make these panels and what additional products would be required.
