The design principle of the module in the off-grid power storage system is to meet the daily power consumption demand of the load under average weather conditions. That is to say, the annual power generation of the solar cell module should be equal to the annual power consumption of the load. Because the weather conditions are lower and higher than the average, the design of the solar cell module should basically meets the needs of the worst season, that is, the battery can basically be fully charged every day in the worst season. But in some areas, the illuminance in the the worst-season is well below the annual average. And if the power of the solar modules is also designed for the worst-case scenario, the rest of the year will generate far more power than is actually needed and causing waste. At this time, it can only be considered to appropriately increase the design capacity of the battery, increase the energy storage, make the battery in a shallow discharge state, and make up for the damage to the battery caused by the lack of power generation in the worst season of light.

The power generation of the components cannot be completely converted into electricity. The efficiency of the controller, the loss of the machine and the loss of the battery must also be considered.

Off-grid systems need to prevent over-design of modules. In some places, customers need to ensure that electricity can be used even in cloudy and rainy days, so they will use many batteries. When customers consider modules, they take all battery capacities into account, and the result is wast too much modules. For example, a system with a daily power consumption of 10KWH, and customer requires to meet the demand for 2 cloudy or rainy days. The normal design can use 4KW modules, but if all battery capacities are included, 12KW modules are required. But only some parts of the modules are used.

For very important places, it is necessary to consider the interval between two cloudy or rainy days. And the system should be equipped with more module.

In Corigy, we provides one-stop solution for complete solar power storage system. You don’t need to worry about how much module need to be used here, we have already configure it for you.