(1) Before maintenance, first disconnect the electrical connection between the inverter and the grid, and then disconnect the electrical connection on the DC side. It is necessary to wait for at least 5 minutes or more to allow the high-capacity capacitors and other components inside the inverter to be fully discharged before carrying out maintenance work.

(2) In the process of maintenance operation, first of all, visually inspect the PV inverter for any damage or other dangerous situations and pay attention to anti-static in the specific operation process, it is best to wear an anti-static hand ring. Pay attention to the warning signs on the inverter and check the surface of the inverter after cooling. At the same time to avoid unnecessary contact between the physical and circuit boards.

(3) After the maintenance is completed, make sure that any faults affecting the safety performance of the inverter have been removed before powering on the inverter.

Cause of occurrence:

(1) No voltage on the AC side of the inverter output, utility power failure.

(2) Inverter AC output terminals are not properly connected or the terminal row is loose.

Solution:

(1) Please use a multimeter to measure the AC output voltage of the inverter, under normal circumstances the output terminals should have phase voltage 380V;

(2) Please test in sequence whether the terminals are loose, whether the AC circuit breaker is closed or not, and whether the earth leakage protection switch is disconnected or not.

Cause of occurrence: 

The voltage and frequency of the AC grid are out of the normal range.

Solution:

(1) Please check the monitoring voltage and frequency history data to determine if there are any values out of the safety regulation range

(2) Please measure the AC grid voltage with a multimeter, if it is really abnormal, then wait for the grid return to normal.

(3)Please check the DC input and AC output of the inverter, let the inverter power off for more than 30min to see if the electrical circuit can be recovered by itself, if it can be recovered by itself, you can continue to use it, if it can’t be recovered, you can contact Renac for repair report.

Cause of occurrence:

Too many modules are connected in series causing the input voltage on the DC side to exceed the maximum working voltage of the inverter.

Solution:

(1)According to the temperature characteristics of PV modules, the lower the ambient temperature, the higher the output voltage. It is recommended to configure the string voltage range according to the inverter datasheet.

(2) In this normal voltage range of the inverter, the inverter efficiency is higher, and the inverter can still maintain the start-up power generation state when the irradiance is low in the morning and evening, and it will not cause the DC voltage to exceed the upper limit of the inverter voltage, which will lead to the alarm and shutdown.

Cause of occurrence:

Generally the PV modules, junction boxes, DC cables, inverters, AC cables, terminals, and other parts of the line to ground short-circuit or insulation layer damage, loose string connectors into the water, and so on.

Solution:

Disconnect the grid, and inverter, check the insulation resistance of each part of the cable to the ground, find out the problem, and replace the corresponding cable or connector!

Cause of occurrence:

There are many factors affecting the output power of PV power plants, including the amount of solar radiation, the tilt angle of the solar cell module, dust and shadow obstruction, and the temperature characteristics of the module.

System power is low due to improper system configuration and installation.

Solutions :

(1) Test whether the power of each PV module is sufficient before installation.

(2) The installation place is not well-ventilated, and the heat of the inverter is not spread out in time, or it is exposed to sunlight directly, which causes the inverter temperature to be too high.

(3) Adjust the installation angle and orientation of the PV module.

(4) Check the module for shadows and dust.

(5) Before installing multiple strings, check the open-circuit voltage of each string with a difference of no more than 5V. If the voltage is found to be incorrect, check the wiring and connectors.

(6) When installing, it can be accessed in batches. When accessing each group, record the power of each group, and the difference in power between strings should not be more than 2%.

(7) The inverter has dual MPPT access, each way input power is only 50% of the total power. In principle, each way should be designed and installed with equal power, if only connected to one-way MPPT terminal, the output power will be halved.

(8) Poor contact of the cable connector, the cable is too long, the wire diameter is too thin, there is voltage loss, and finally cause power loss.

(9) Detect whether the voltage is within the voltage range after the components are connected in series, and the efficiency of the system will be reduced if the voltage is too low.

(10) The capacity of the grid-connected AC switch of the PV power plant is too small to meet the inverter output requirements.

Cause of occurrence:

The cause of that the inverter system switch is turn off.

Solution:

(1) Press the inverter screen confirmation button to enter the main menu – “SysSwitch”.

(2) Set “SYS Switch” to “On” and press hold the confirmation button.

Cause of occurrence:

(1) The PV input voltage does not reach the minimum start-up voltage of the inverter.

(2) The meter is not connected to the communication cable or the communication is faulty.

(3) The inverter is not connected to the meter, but the meter is enable in the inverter menu.

Solution ：

(1) Please check whether the inverter PV input voltage reaches the minimum start-up voltage of the inverter.

(2) Please check whether the meter is installed or not, if not, you need to “Disable” the meter function in the inverter menu. Entrance“Setting”-“Advanced”-”Feature” – “Meter Setting”. Set ”Disable” in the ”Meter Setting”

(3) Please check if the communication cable of the meter is connected correctly (RS485-A and RS485-B are connected correctly). If the above troubleshooting is OK but the problem remain, please try to replace the meter.

Fault Description:

The inverter does not recognize the battery, cannot read the battery SOC, and the battery SOC shows “N/A”.

Cause of occurrence:

(1) BMS communication failure between inverter and battery.

(2) Batteries is not turned on or BMC failure.

(3) The battery is not matched with the inverter.

Solution:

(1) Please check if the BMS communication cable is correctly connected between the battery and the inverter. 

(2) Please check if the DIP switch is set correctly on the inverter. The communication address must be set correctly for the inverter and battery to communicate properly. Below is the diagram of the communication address dip switch on the BMC:  

(3) Please check if the battery BMC LED is green lighting.

(4) If the BMC may be faulty. Please try to be replaced.

Cause of occurrence:

(1)The inverter is not connected to the meter but the meter enable is set on the inverter

(2)The meter communication RS485-A and RS485-B communication wires are connected incorrectly.

Solution:

(1) Please check the meter setting, if not connection, please set ”Disable” the meter function in the inverter.

 Enter “Feature” – “Meter Setting”. Set ”Disable” in the” Meter1 Setting”   

(2) If the meter is already installed, check if the communication cable of the meter is connected correctly (RS485-A and RS485-B are connected correctly).

(3) If all the above troubleshooting is OK but the problem remain, please try to replace the meter.

Cause of occurrence:

When the system has no PV and only the power grid, and no load power for 3 minutes, the inverter enters Idle mode, this is a normal phenomenon.

Solution:

When the inverter connect to the PV and batteries etc. then get the inverter is running.

Q13：Why the battery is not charging?

Cause of occurrence:

(1) There is insufficient PV power to charge the battery (or the inverter is faulty status).

(2) The battery is not communicating with inverter.

(3) The battery is protected situation, such as temperature protection, or the cell voltage difference is too large.

(4) The battery BMC or battery is malfunctioning.

Solution：

(1) Please check for proper communication between the inverter and the battery.

(2) Make sure there is sufficient PV power to charge the battery.

(3) Please check the battery history information to see if the battery is restricted from charging for some reason.

(4) If the battery is still not charging, please try to contact with Renac after-sale service.