The solar panels will generate DC electricity once the sun hits their surfaces, but they do not store electricity, they need batteries to store such generated electricity inside.
The solar panels are manufactured from semiconductor materials like silicon, and they produce DC electricity through a process called photovoltaic.
Under photovoltaic process, the semiconductor materials will exposure when the sunlight hit it, so the DC current will be generated. But we can not use DC current directly to power our home appliances, so a solar inverter is used to convert DC current to AC current which is suitable to power our home appliances. And based on our solar system type, weather it connects to the grid or stand alone, we decide the type of the solar inverter to be used on our system. Most of home-owners prefer to connect their solar system to the grid, so in case of insufficient solar energy, their appliances can automatically be fed from grid electricity, and that called net metering system.
The solar panels generated electricity will be stored on Lithium ion batteries for future need, because this battery have the ability to reverse their chemical reactions and feed our loads with electricity in night time or insufficient solar energy day time. Of course, the amount of energy the batteries can store depends of their capacities, and what makes us prefer lithium batteries types, is that they are low cost and light weight in comparison with other batteries types.
Using solar panels plus batteries will not enable us to export electricity to the grid and get accredit from the electric utility, but it helps us saving money in 2 cases;
- When the electric utility charges us based on time of use.
- When the electric utility does Not provide Net Metering tariff in our living area.
- When the electric utility supply is Not stable in our area, so it disconnects in most of time, and we usually lose the power.
Solar batteries always store DC electricity, and dispense it over long time period, so we have to use the most powerful and reliable type, so we can confidently depend on them.