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A PV on-grid inverter is solar power, home grid, and public grid connected together, and must rely on the current grid to generate electricity. Mainly consists of inverter and solar panels, PV grid-connected inverter will send and receive energy directly to the grid, and the excess electricity will be directly delivered to the public grid. When there is a shortage of power generation, it will be automatically replenished from the grid. If the electricity is to be stored during the day, batteries and controllers will be added.
PV off-grid inverters require energy storage and do not need to send power to the grid. Power generation system that can be operated directly without relying on the grid, PV off-grid inverter is mainly composed of solar panels, energy storage batteries, charge/discharge controllers, inverters and other components. It is mainly suitable for use in areas with frequent power outages or without electricity or grid, and has very strong practicality.
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A Failure Analysis
There is no battery DC input and the inverter LCD power is supplied from the battery.
Possible causes
1. Battery voltage is not enough. When the battery is just shipped from the factory, it is usually fully charged, but the battery will slowly discharge (self-discharge) if it is not used for a long time. Off-grid system voltage of 12V, 24V, 48V, 96V and other kinds of applications to more than one battery in series to meet the system voltage, if the connection cable is not done, will also cause the battery voltage is not enough.
2. Reverse battery terminals. Battery terminals have positive and negative poles, generally red to the positive pole, black to the negative pole.
3. DC switch is not closed or switch failure.
Solutions
1. If the battery voltage is not enough, the system can not work, the solar energy can not charge the battery, go to another place to find a place to charge the battery to more than 30%.
2. If it is a line problem, use a multimeter voltage gear to measure the voltage of each battery. When the voltage is normal, the total voltage is the sum of the battery voltage. If there is no voltage, in order to detect the DC switch, terminals, cable connectors, etc. whether normal
3. If the battery voltage is normal, the wiring is normal, the switch is open, the inverter still does not display, it may be the inverter failure, to notify the manufacturer overhaul.
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A Failure analysis
The battery is charged by the PV module and the controller, or the utility and the controller.
Possible reasons
1. Component reasons: insufficient component voltage, low sunlight, bad wiring of component and DC cable.
2. Bad wiring of the battery circuit.
3. The battery is fully charged and has reached its maximum voltage.
Solution
1. Test whether DC switch, terminal, cable connector, component, battery, etc. are normal in turn. If there are multiple components, separate separate access test.
2. When the battery reaches full charge, it can not be recharged, but different batteries have different voltages when they are fully charged, such as the rated voltage of 12V battery, the voltage is between 12.8~13.5V when fully charged, which is mainly related to the specific gravity of electrolyte when the battery is fully charged. According to the type of battery to adjust the maximum voltage limit.
3. Input overcurrent: the charging current of the battery is generally 0.1C-0.2C, the maximum does not exceed 0.3C, for example, 1 lead-acid battery 12V200AH, the charging current is generally between 20A and 40A, the maximum can not exceed 60A. the component power should be matched with the controller power.
4. Input over-voltage: the input voltage of the component is too high, check the voltage of the battery board, if it is really high, the possible reason is that the configuration of the battery board has too many strings, reduce the number of strings of the battery board.
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A Failure analysis
The load power is greater than the inverter or battery power.
Possible reasons
1. Inverter overload: Inverter overload exceeds the time range, load power exceeds the maximum value, adjust the load size.
2. Battery overload: discharge current is generally 0.2C-0.3C, the maximum does not exceed 0.5C, 1 12V200AH lead-acid battery, the maximum output power does not exceed 2400W, different manufacturers, different models, the specific value is not the same.
3. Loads such as elevator can not be directly connected to the inverter output, because when the elevator is descending, the motor reverses and generates a reverse electromotive force, which enters the inverter and damages the inverter. If an off-grid system is necessary, it is recommended to add an inverter between the inverter and the elevator motor.
4. Inductive loads have too much starting power.
Solution
The rated power of the load should be lower than the power of the inverter, and the peak power of the load should not be greater than 1.5 times of the rated power of the inverter.
