The photovoltaic off-grid power generation system is very suitable for the needs of distributed power generation. It is the first choice for places with insufficient power supply. It is mainly composed of photovoltaic modules, brackets, controllers, inverters, batteries and power distribution systems.

　　Photovoltaic off-grid power generation system cannot solve all power consumption problems. It also often encounters the following problems that need to be paid attention to and solved:

　　1. Photovoltaic modules, inverters, and batteries should be matched during design

　　The parameter of any one component cannot be too large or too small. When designing, novices often calculate the power consumption too much. For example, a 300W refrigerator runs for 24 hours according to the theoretical value of full power, which is calculated as 7.2 kWh, which causes the capacity of the energy storage battery to be too large and the system cost is too high.

　　2. Inverters cannot be connected in parallel

　　The phase and amplitude of the voltage and current at the output of each inverter are different, and the inverter does not support parallel connection of the output.

　　3. It is best not to connect the inductive load to the output terminal of the inverter

　　Because the inductive load will produce a back electromotive force when the current changes rapidly, such as the reverse rotation of the motor, which will damage the inverter. If an inductive load must be used, it is recommended to add a frequency converter between the inverter and the motor.

　　4. The insulation of the components should be done well

　　If the component has leakage current to the ground, it will cause the leakage switch to trip.

　　5. The voltage of the photovoltaic module and the voltage of the energy storage battery must match

　　It is recommended that the voltage of the photovoltaic module is between 1.2-2.0 times the voltage of the energy storage battery. If it is a 24V energy storage battery, the input voltage of the photovoltaic module is recommended to be between 30-50V. Of course, this depends on the parameters of the MPPT controller.

　　6. The output power of the photovoltaic module and the power of the controller should be similar

　　For example, a 48V30A controller with an output power of 1440VA, it is recommended that the power of the photovoltaic module should be around 1500W.

　　7. The charging and discharging current of the energy storage battery is generally 0.1C-0.2C, and the maximum does not exceed 0.3C

　　This parameter is mainly designed in accordance with the requirements of lead-acid batteries, because lead-acid batteries cannot be charged with too much current, otherwise the life will be greatly lost. In fact, the lithium iron phosphate battery has completely replaced the lead-acid battery, and it can be charged at a full power of 1C.