Maximum efficiency
Inverter efficiency for solar panels.
The efficiency indicator is the percentage ratio between the amount of energy that the device delivers to the load and the energy consumed from the solar panel. The higher this parameter, the more efficient the operation of the device and the lower the losses during conversion. In modern inverters for solar panels, efficiency values of up to 90% are considered average, and above 90% are considered good.
Maximum AC power
The maximum current in amperes (A) that the inverter, when operating, is capable of outputting without overloads or failures.
Max. power
The maximum allowable input power from solar panels, expressed in kilowatts (kW). Let us remember that 1 kW contains 1000 W.
When selecting an inverter based on this indicator, they are based on the total power of the solar panels involved in generating electricity. Moreover, it often makes sense to select models with an inverter input power slightly less than the maximum power of solar panels - for example, if they are shaded part of the time or for other reasons do not receive enough sunlight during the day. The power of the solar battery should not exceed the power of the inverter by more than 30%. However, for some inverters the excess can be only 10%, while for others it can be up to 100%. It is better to clarify this point in advance.
Operating voltage PV
The operating range of the inverter is usually located between the starting voltage and the maximum voltage. This interval is indicated in volts.
Short circuit current
The maximum solar panel short circuit current that the inverter can accept without the risk of breakdown or emergency shutdown. The parameter is usually indicated in amperes.
Functions
—
UPS function. Inverters with a UPS function automatically switch to battery-powered mode when there is insufficient power generation from solar panels or in cases where the main power source is disconnected. This ensures load redundancy. Note that switching may not occur instantly, but with a certain delay (about 10-30 ms).
—
Connecting the generator. Inverters that support the generator connection function significantly increase the reliability and efficiency of autonomous solar energy systems. In practice, the function can be implemented in several basic ways. First, the system can automatically turn the generator on and off depending on the battery charge level or current power consumption, ensuring efficient use of resources and minimizing fuel consumption. Secondly, switching the load to the generator can be carried out when there is a shortage of electricity generation from solar panels. And thirdly, the generator can be used to maintain an optimal battery charge level so that the system is in full readiness at any time.
—
Parallel connection. The inverter has special connectors through which two or more devices can be connected to a single electrical network. Parallel connection is used when one inverter is not able to pull the entire load from solar panels and the input power exceeds the capabilities of the device itself.
—
Built-in monitoring. The presence of a built-in monitoring module on board the inverter, which collects information about the productivity of solar panels, allows you to monitor energy production and consumption, as well as monitor the performance of the system as a whole. Moreover, these parameters can often be viewed and controlled in real time (including through a mobile application for a smartphone). The monitoring module is usually connected to the Internet via a Wi-Fi network.
Control interfaces
Connection interfaces provided in the inverter design for solar panels.
-
RS232. A specialized communication interface used to directly connect the inverter to a computer. As a rule, the interface provides the ability to monitor solar generation systems around the clock using a local network. Also, the RS232 connector can be used to communicate several inverters with each other, or, less often, for software updates or service testing.
-
RS485. A connector often used to connect several inverters to a central hub, which, in turn, connects to a computer. This connection can be useful for setting up a solar generation system or sending monitoring data over the network.
-
USB. A standard USB port is often used for configuring equipment via a wired connection to a computer or for inverter firmware updates.
-
LAN (RJ45). The presence of a LAN connector (RJ45) in the inverter design. Such ports are standardly used for wired connections in computer networks using a twisted pair cable.
-
Wi-Fi. Wi-Fi communication module for wireless connection of the inverter to a computer, laptop or mobile phone. Using specialized software, you can receive monitoring data from the inverter directly “over the air” - transmitting information over a Wi-Fi network eliminates the
...fuss with wires.
— Bluetooth. Option to wirelessly pair the inverter with smartphones, tablets or laptops via Bluetooth. Thanks to data synchronization, the user will be able to monitor equipment performance and remotely control the inverter within range of the Bluetooth wireless network.Noise level
The noise level in decibels (dB) produced by the inverter during operation. The lower this indicator, the more comfortable the use of the equipment will be, which is especially important for residential premises.
Note that decibels are a non-linear quantity, so the easiest way to assess the noise level is to use comparative tables. Here is a simplified table for the range that most modern inverters fall into:
35 dB – conversation in muted tones;
40 dB – quiet conversation; maximum noise level allowed in residential premises during the daytime;
45 – 50 dB – conversation in a normal tone;
55 dB - background noise in an office without special noise sources;
60 dB - loud conversation;
65 dB - city street with average traffic intensity;
70 dB - a conversation between several people in a raised voice.
Casing protection class
The protection class of the housing is traditionally indicated according to the IP standard - the “IP” marking with two numbers. The first describes protection against the penetration of dust and foreign objects. The following options may occur:
— 2. Protection against objects with a thickness of 12.5 mm or more, prevents the penetration of fingers.
— 3. Protection against objects with a thickness of 2.5 mm, in particular many tools.
— 4. Protection from objects with a thickness of 1 mm (most wires).
— 5. Complete protection from contact of the “internals” with foreign objects, resistance to dust (it can penetrate inside the case, but in scanty quantities that do not affect the operation of the device).
— 6. Completely closed housing, preventing dust from getting inside.
The second digit in the IP marking characterizes the degree of protection against moisture:
— 0. Complete absence of any protection; water ingress into the housing is not allowed.
— 1. Protection from vertical drops of water.
— 2. Protection against vertical drops when the body is tilted up to 15° from the standard position.
— 3. Protection against splashes falling on the body at an angle of up to 60° to the horizontal, the minimum indicator that allows us to talk about resistance to rain.
- 4. Protection against splashes from any direction, allows you to safely withstand rain and strong winds.
— 5. Protection from water jets from any...direction, resistance to storms.
— 6. Protection from strong water jets or strong sea waves (when the device can be completely hidden under the wave for a short time).
— 7. Possibility of short-term immersion to a depth of up to 1 m (without the possibility of constant operation in submerged mode).
— 8. possibility of long-term immersion to a depth of more than 1 m (with the possibility of constant operation in submerged mode).
The degree of IP protection is especially important to consider when choosing outdoor models - they are the ones most susceptible to adverse environmental influences. This parameter is also important when placing the inverter in rooms with high humidity levels.
