After the photovoltaic system is installed ( download the installation manual pdf file ), how to judge whether your system connection is correct?
It is not enough to simply consider the start-up of the inverter and the transmission of power.
Because electricity is complex, even if you make the wrong connection, you can keep the solar system working for a while, but at the same time, it will continue to damage the components inside the photovoltaic system.
It is possible that one day, a circuit failure will occur, leading to more serious situations, such as explosions and fires.
Read this article to solve these problems in advance.
PVMars will start with solar panels, combiner boxes, controllers, inverters, batteries, and other components from the case of Brazilian farms.
Use our commonly used multimeter to measure the voltage of each part of the photovoltaic equipment to determine whether the system is connected correctly.
So that you can use the photovoltaic system in the future with more peace of mind and safety.
What does a 30kW photovoltaic system include?
This is a set of solar energy storage systems installed in Brazil to continuously provide 24-hour power for farms with insufficient power supply.
Farmers have purchased production equipment from China and the United States, so there are two types of AC voltages, namely 110v-120v and 220v-240v.
For the dual-voltage solution, PVMars has designed an inverter that can output two kinds of AC voltages at the same time. —- Click the orange text to get more dual voltage design details.
Through the equipment power load meter provided by the farmer and online video communication with PVMars solar experts, we can conduct local sunshine surveys, solar power calculation, design, and other steps.
Finally, this photovoltaic system presents:
64 x 450w TOPCon solar panels — 4 x 16 solar panels connected in series
1 x H4T PV combiner
1 x 384Vdc 60A MPPT controller/charger
1-unit x 384Vdc 30kW IGBT inverter/output 110Vac-240Vac
32 x 12V150Ah gel battery
The solar brackets in this solution are customized.
PVMars will customize your exclusive fixed brackets according to the needs of different scenarios.
In addition, we have 16 years of experience in photovoltaic system installation.
Each system provides installation tools.
It is a complete set of photovoltaic equipment provided to you, letting you install it worry-free. You can click on the orange text to view related installation videos.
So how to connect this system correctly?
Correct connection steps for photovoltaic systems:
Please note that in a solar energy storage system, the battery is always the primary connection configuration.
After connecting the battery to the inverter, turn on the inverter and use the battery pack alone to work.
Then, we use a multimeter to check whether the voltage at the output port of the inverter is correct.
After running well, connect the mains power and electrical loads (if there is no mains power, only consider the load).
Next, we explain in detail which data is correct.
1-Solar panel
To obtain relatively accurate data, it is recommended to conduct measurements in sunny weather.
450W solar panel Voc/39.04V, Imp/13.97A.
After 16 x 450W solar panels are connected in series, the total voltage is 16 x 39.04V = 624.64V
A total of 4 pv arrays are connected to the PV combiner in parallel.
Please look at the picture below.
We use a multimeter to measure each group of circuit breakers of the PV combiner.
Because some power will be lost during wire transmission, the resulting voltage range should be considered correct around 600V.
The output of the PV combiner is connected to the MPPT controller, and the controller here is equivalent to charging solar energy into the battery.
Therefore also called the MPPT charger, will connect the output of the controller to the battery pack.
The installation tools provided by PVMars include 1P-2P circuit breakers for safer and more convenient use.
2- Battery
All 32 12V gel batteries are connected in series to form a group and connected to the battery input port of the 30kW inverter.
It should be noted that before connecting to the inverter, we must ensure that all switches of the inverter are closed and no electrical equipment is connected.
After the connection is completed, we use a multimeter to measure from the battery input end of the inverter.
The resulting voltage range is considered to be correct when it is 384V±10V.
If this mark appears on the multimeter, it means that you have connected the positive and negative terminals incorrectly.
The positive and negative poles should be swapped to the correct position.
3- Connect to mains power
If you do not consider connecting to mains power, you can ignore this.
It is very important that every time you connect the wires to the inverter, be sure to confirm that all switches of the inverter are closed and in the off state.
When connecting to mains power, you need to turn off the main switch in the house to ensure that no circuit is open. Avoid accidents.
Having said that, the inverter has a port to connect to the main power, and the color of the AC wire is different in each region. The farmer’s mains wiring in this case looks like this:
2 live wires and one neutral wire. Different AC voltages correspond to different electrical equipment.
Note that the overload protection port of the inverter design is at L2.
This means that if you have a lot of 220V electrical appliances, it is recommended to connect the 220V live wire to the L2 port. — L1+L2 = 220Vac
This protects you from turning on too much load, which can cause circuit failure.
Finally, use a multimeter to measure the voltage of each output port. If the range is 110v-240v±10%, it is considered correct.
Correct opening steps for the inverter:
In off-grid solar systems, the correct startup and shutdown sequence of the inverter is very important.
Incorrect operation may cause damage to the inverter.
Start-up sequence of photovoltaic system:
1- Turn on the battery air switch
2- Turn on the battery switch of the inverter
3- Turn on the PV side switch of the combiner box
4- Turn on the inverter output
Finally, you can turn on the electrical load
Important note: It is prohibited to turn on the output switch of the inverter when the electrical appliance has been turned on. We can add a circuit breaker between the inverter and the load for control.
Shutdown sequence:
First, turn off the load.
Secondly, turn off the output switch of the single-phase/three-phase inverter.
Third, turn off the PV combiner switch.
Fourth, turn off the battery switch of the inverter, and finally, turn off the air switch connected to the battery.
A photovoltaic system is always a power generation device and it is recommended that you read this article carefully and communicate with your electrical installer.
If you have electrical knowledge, please click on the orange highlighted font, and hope to cooperate with you in depth.
Final tips:
In photovoltaic systems, gel batteries are different from lithium batteries in that they do not have a built-in heat dissipation system and BMS.
We can add a battery organiser for precise control.
At the same time, gel batteries should be separated by at least 5 cm from each other to ensure heat dissipation and ventilation between them. Avoid thermal runaway causing safety issues.
PVMars’ professional team always thinks about your safety and property.
