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Should the power station be connected to the grid or not?
- Jul 13, 2018 -

When people prepare to install a photovoltaic power station on their roof, they often struggle with the question: should they choose to connect to the grid or off the grid, do they need batteries? The difference is described briefly below.

Grid photovoltaic power station and grid connection is together, there is no electricity grid photovoltaic power station device, directly through the inverter into the national grid voltage requirements, and the priority for the use of family, family to burn electricity can be sold to the country.

Off-grid photovoltaic power stations store solar power in batteries and convert it into a 220V/380V voltage for home use via a inverter.

The difference between the two is as follows:

Grid-connected photovoltaic power station.jpg

1. Grid-connected photovoltaic power station

Grid-connected photovoltaic power station need to be connected to the public power grid, that is, solar power generation, home power grids, and public power grids must be connected, and must rely on the existing power grid to operate the power generation system.

The grid-connected photovoltaic power station is mainly composed of solar panels and inverters. The solar panels are directly converted into 220V/380V AC by the inverter and supply power to the household appliances. When the amount of solar energy generated exceeds the amount of electricity used by household appliances, Excess electricity is delivered to the public grid; when solar power does not meet the needs of household appliances, it is automatically replenished from the grid. And the whole process is intelligently controlled and does not require manual operation.

Since this photovoltaic power generation system does not require the use of a battery, it also saves a lot of cost. Therefore, if you want to save electricity costs and the power supply is convenient, then choose the grid-connected solar power system, which is the current mainstream way.

Off-grid photovoltaic power station.jpg

2. Off-grid photovoltaic power station

Off-grid photovoltaic power stations are independent power generation systems that do not depend on the power grid. Off grid photovoltaic power stations are mainly composed of solar panels, energy storage batteries, charge and discharge controllers, inverters and other components. The electricity sent by the solar panel directly flows into the battery and stores it. When it needs to be supplied to the electric device, the DC current in the battery is converted to the alternating current of 220V by the inverter. This is a repeated cycle charge and discharge process. This kind of power generation system is widely used because it is not restricted by the region. As long as it has sunlight, it can be installed and used, so it is very suitable for remote non grid area, isolated island, fishing boat, outdoor breeding base and so on. It can also be used as an emergency power generation equipment in the area of power outage.

This system must be equipped with battery and occupy the cost of 30-50% of power generation system. Moreover, the service life of the battery is generally 3-5 years, and then it has to be replaced, which increases the use cost. From economic considerations, it is difficult to promote the use of a wide range, so it is not suitable for use in electricity convenient places. But for families without power grids or frequent power outages, they are also very practical. In particular, in order to solve the lighting problem of power failure, DC energy saving lamps can be used, which is very practical. Therefore, the off grid power generation system is specially designed for locations without power grids or frequent power outages.