90W solar power supply system configuration

1. Selection of battery capacity

Assuming that the average power consumption of the electrical equipment is 90W and the entire system uses the 12V DC power storage system to convert into 220 volts AC power supply, the daily power consumption of the system is 90 watts /12 volts x 24 hours =180 (Ah). If the battery pack capacity is sufficient for the system to work continuously for three days in rainy weather, the minimum battery pack capacity is 540 (Ah) : 180Ah x three days. Although the nominal capacity of the battery is its rated discharge capacity, the best choice for the battery used in the solar support picture energy system is the deep circulation type maintenance-free lead-acid battery. In general, the system reliability is the best when the power depth is 50%-80%. We only according to 50% discharge depth to design, in order to have a certain amount of wealth, the design of the total capacity of Beijing solar energy company is: 540Ah/0.5 = 1080 Ah. In this way, the total capacity of the battery is calculated, the capacity of 1200Ah to reach the system for 24 hours running for 3 consecutive rainy days can also operate normally the power supply requirements, the battery is DC12v, the best combination of the battery should be :2V1200Ah battery 6 series installation.

2, the choice of solar panels

A solar cell array consists of one or more solar cell modules. If there is more than one bracket picture, the solar bracket picture and voltage of the module should be basically the same, and the bracket picture series and parallel combination loss. According to the solar radiation parameters and load characteristics of the system installation site, the total power of the solar cell array is determined. According to the voltage and current requirements of the designed system, the number of solar cell array series and parallel modules is determined. At present, the daily effective sunshine time of the system installation is calculated as 6 hours, and the power output of the solar panel is calculated by taking into account the charging efficiency and the loss in the charging process and the inverter process. If the system works continuously for 24 hours and the average power is 90w, the rated power consumed every day is 2160Wh 90W*24 hours. Taking into account the loss of power devices with charging control and inverter control in the system, taking 0.9 as the inverter efficiency parameter value of what brand of solar energy is good, then the total power required by solar panels in the solar support picture should be: 2160Wh/0.9 = 1944Wh. In the actual charging process of solar cells, the actual power factor of solar cells will be affected by the weather in the picture of solar support. The actual power factor of solar cells is generally calculated as 0.7, and the total power of solar panels required is calculated as the effective picture time of solar support is 6 hours per day: 1944Wh/6 hours /0.7 = 462.86W, so the solar panel design is 18V500W.

3. Design of solar panel bracket

The solar cell array bracket is used to support the solar cell module. The structure design of the solar cell array should ensure that the module is securely connected to the bracket, and the solar cell module can be easily replaced. The solar cell array and support must be able to withstand winds of 120km/h without being damaged. The bracket can be tilted or installed at a fixed Angle so that the solar array can generate the most electricity during the design month, when the average daily radiation is lowest. All phalanx fasteners must be strong enough to secure the solar cell assembly reliably to the phalanx support. Arrays of solar cells can be mounted on the roof, but the brackets must be attached to the main structure of the building, not to the roofing material. For a ground-mounted solar cell array, the minimum spacing between the solar cell modules and the ground should be at least 0.3m. The bottom of the column must be securely attached to the foundation in order to withstand the weight of the solar cell array and withstand the designed wind speed.

4. Selection of solar charging controller

Charge and discharge controller can be used alone, or can be made into an integrated machine with the inverter.

The charge and discharge controller shall have the following protection functions:

a) Circuit protection that can withstand load short circuit;

b) Circuit protection that can withstand load, solar cell module or battery polarity reverse connection;

c) Can withstand the circuit protection of internal short circuit of charge and discharge controllers, inverters and other equipment;

d) Able to withstand breakdown protection caused by lightning strikes in minefields;

e) Protection against reverse discharge of the battery through the solar cell module.

For systems with solar array power (peak) greater than 20W, the controller itself should have the function of battery full disconnect (hvd) and undervoltage disconnect (lvd). In the solar wireless dispatching system, the peak power of the solar panel selected is 500W, and the charging voltage is 12V. Through this data, the maximum working current of the solar charging controller can be calculated as 500W/12V.