How to choose battery for solar photovoltaic inverter

The difference between off-grid and grid-connected

Grid-connected: A power generation system that must be connected to the public grid, that is, solar power, home grids, and public grids are linked together and must rely on the existing grid to operate. The grid-connected photovoltaic power station has no electric energy storage device, and is directly converted into the voltage required by the national grid through the inverter.

Off-grid: Also known as an independent photovoltaic power station, it is a power generation system that operates independently without relying on the grid. The electricity emitted by the solar panel directly flows into the battery and is stored. When it is necessary to supply power to the electrical appliance, the DC current in the battery is converted into 220V AC by the inverter. This is a repetitive cycle of charging and discharging. The system must be equipped with a battery.

Why choose an off-grid power supply system?

The off-grid power supply system is specially designed for use in areas without power grids or places with frequent power outages. It is a rigid demand. It relies on the working modes of "storage and use" and "first-storage and then-use" to provide users with help and services that "deliver charcoal in the snow".

The system operates independently without relying on the power grid and is not subject to geographical restrictions. It can be installed and used as long as there is sunlight. It is widely used in remote areas without power grids, isolated islands, fishing boats, communication base stations, street lamps and outdoor breeding bases. Emergency power generation equipment in power outage areas.

The role of energy storage batteries

In the photovoltaic off-grid system, the energy storage battery occupies the main part, and its main task is to store energy, ensure the stability of the system power, and ensure the load power consumption at night or in rainy days.

Energy storage function: The photovoltaic power generation time and the load power consumption time are not necessarily synchronized. The photovoltaic off-grid system can generate electricity only when there is sunlight. The power generation reaches the highest at noon, but the electricity demand is not high at noon. Many household off-grid power stations are in Electricity only at night. Therefore, the electricity generated during the day needs to be stored by the battery first, and then the electricity is released when the electricity peaks.

Stable system power: Photovoltaic power and load power are not necessarily the same. Photovoltaic power generation is affected by radiation and is in a fluctuating state, and the load side is not very stable. The starting power is greater than the daily operating power of the load end. If the photovoltaic power generation end is directly connected to the load, it is easy to cause the system to be unstable and the voltage to fluctuate. The energy storage battery is a power balance device at this time. When the photovoltaic power is greater than the load power, the controller sends the excess energy to the battery pack for storage. When the photovoltaic power cannot meet the load demand, the controller sends the battery power to the battery. towards the load.