How to design an off-grid solar energy storage system?


1.Why solar energy storage system?

The biggest difference between the off-grid system and the on-grid system is that the on-grid system takes the investment return as the calculation premise, while the off-grid system takes the rigid demand power supply as the basic, so  they will have a different focus in the selection of components. Generally, off-grid systems are mainly installed in areas where have no grid, or the grid is far away to connect, or the electricity bill is rather expensive, but how to make the electricity generated by solar power not wasted, and guarantee the electricity demand be satisfied when the solar power generation is insufficient? Here, we can use energy storage batteries to store the surplus electricity generated by the solar system and discharge the electricity from batteries for daily use when the solar power generation is not enough. Then how to design an applicable off-grid solar energy storage system (hereinafter referred to as off-grid SESS)?

2.Parameters to an off-grid SESS

Ⅰ.The power of appliances

Ⅱ.The operation time of the appliances

Ⅲ.Take the power supply during rainy day into consideration or not

Ⅳ.The Lighting conditions and optimum mounting angle

3.Components of Off-grid SESS

Solar panels(modules),Off-grid Inverters, Batteries, Mounting System, other accessories.

Ⅰ.Solar Panels

Solar panel are indispensable main component of the solar system, and the quality of the components directly affects the power generation and service life of the entire system. With the upgrading of technology, the experimental efficiency of Topcon solar panel has reached 25.4%, and the mass production efficiency has also reached 23%~24.5%. PANELROOF Topcon solar panel are produced by Tier1 manufacturers, with the highest efficiency reaching 22.44%, 87.4% /30 years linear warranty, and 20 years product warranty. PANELROOF Topcon solar panels had been applied to many important projects around the world.

Ⅱ. Mounting System

According to the material and coating, solar mounting brackets can be roughly divided into aluminum alloy, galvanized, aluminum magnesium zinc bracket. At present, aluminum alloy bracket is most widely used because it is easy to form, easy to process, corrosion resistance, light and easy to install, and high recyclability. PANELROOF solar brackets factory has more than 20 years of experience in the production of aluminum alloy brackets, and the products had highly praised by domestic and oversea customers.

Ⅲ.Off-grid Inverter

The choice of inverter is mainly based on the AC side appliances. Generally, the appliances divided into three categories: resistive load (lights, heaters, etc.), inductive load (air conditioner, motors, etc.), capacitive load (capacitor, etc.). Considering the starting current of the inductive load is 3 to 5 times of the rated current, but the short-term overload capacity of the general off-grid inverter is up to150-200%, so when the inductive loads connected to the system, calculate them in double or more. For example, if you want to drive 2P(2*750W) air conditioning, the inverter with a rated power of 3KVA and above would be normal configuration. Usually, three types of loads are all included in daily life, the most will impact more of the system configuration. PANELROOF low frequency off-grid inverter with MPPT controller built in, more intelligent, more stable and wide range of powers for choice.

Ⅳ.Energy Storage Batteries

There are types of batteries in the market, but for SESS, lead acid batteries and LiFePo4 batteries are generally used. But consider the volume, life time and environmental impact, the LiFePo4 batteries has become the mainstream. PANELROOF is one of the LiFePo4 batteries manufacturer and supplier from China. We have different types of lithium batteries to meet different application scenarios.

In conclusion, the main of SESS is the batteries, but solar panels and inverters are the primary equipment, other accessories can be configured according to the system and local conditions, PANELROOF provides the design consultation of the entire system configuration, provide users with a complete system service.