When the user chooses to install home solar photovoltaic power generation system, we must first acknowledge using off-grid or grid, solar power system which is currently two main ways, functions are not the same, there are great differences in the cost. But perhaps many users still do not understand off-grid and grid What is the difference, make a brief explanation: first, the off-grid solar power systems, also known as independent photovoltaic power generation system is not dependent and independent running system, mainly solar solar panels, storage batteries, charge controllers, inverters and other components. The electricity solar panels and stored directly into the battery, to the electrical power supply to the battery in the direct current flowing through the inverter and converted into 220V AC, which is a repeating cycle of charge and discharge process. Because of this power system without geographical limitations, the use of a very wide range, as long as there is sunlight can install and use, it is very suitable for remote off-grid areas, islands, boats, outdoor breeding base, etc., can also be used as frequent power outages regional emergency power generation equipment. Because such a system must be equipped with batteries, and occupy 30-50% of the cost of power generation systems. And the battery life is generally 3-5 years, after which they have to be replaced, which is an increase of the cost. The economy, it is difficult to get a wide range of promotional use, so is not suitable for a convenient place to use electricity. But for non-grid areas or frequent power outages families, but also very practical. Particularly simple to solve the blackout lighting problem, you can use the DC energy saving lamps, very practical. Therefore, the off-grid power system is designed for non-grid areas or places of frequent power outages region. Second, grid-connected solar power systems and networks that must be connected to the public grid, is solar power, home network, linked to the public grid, which must rely on the existing power grid to run the power generation system. Mainly by solar panels and inverters composition, issued directly by the solar panels into 220V AC inverter and power supply to the appliance, when the solar generating capacity over household electricity use, the excess electricity to convey to the public Power; when solar power can not meet the household use, it is automatically added from the grid. This entire process is intelligent control, no human on or off. This system eliminates the use of batteries pool, saving the cost of the system, especially this year three copies issued by the national grid on solar and other new energy grid Deal has expressly allow free network, excess electricity can be sold to power companies . From a long-term investment perspective, the cost can be recovered in a few years there is the possibility of profit. Therefore, if you want to save electricity costs and electricity supply convenient, on the choice of grid solar power system, which is now or in the future mainstream approach. However, the grid also has its drawbacks, is that when the public grid power outage, solar photovoltaic power generation can not be run.