For the solar system, many people are familiar with it. A photovoltaic system, also PV system or solar power system, is a power system designed to supply usable solar power by means of photovoltaics. It consists of an arrangement of several components, including solar panels to absorb and convert sunlight into electricity, a solar inverter to change the electric current from DC to AC, as well as mounting, cabling and other electrical accessories to set up a working system. When you going to buy some products, many of sales will ask you the gird-tie system or off-gird system…. How hard for me to tell the system, I even don’t know what’s it. I believe many of the people have the same feelings. Today, I am going to help you to understand them. The gird-tie solar system has two types. The first one is Large power station, these projects usually have more than 100kw system. The second one is Distributed power station, these projects are usually installed in the roof. Many people will choose them to power generation and provide to their own inquires or sell it to the government. I believe that many people have installed them and understand what I am saying. For the off-gird system, The phrase refers to systems that have no connection with the utility grid, and must make all the electricity necessary for the home, business, or application. In fact, The LED lights with panels in the garden、the solar pump in your pool、the portable solar battery when you are travelling outside. These are the off-gird products and it needs you to choose the correct products to install the system to charge them. Now, I am trying to help you understand them. For an off-grid solar system you may need four basic components 1. Solar Panel (PV Panel) 2. Charge Controller 3. Inverter 4. Battery ① Solar Panel We usually have use the common solar panel. The power from 5w-100w.But Now more and more people like the foldable panels. It’s easy to take it when we are travelling.