Rated power
The rated output power of the inverter, expressed in volt-amperes (VA). Essentially, this value is equivalent to power in watts (W).
This parameter refers to the power that the device can continuously deliver to consumers. When choosing based on this parameter, ensure that the rated power of the inverter exceeds the expected load power by approximately 15-20%. Additionally, keep in mind that some electrical appliances (particularly those with electric motors, such as vacuum cleaners, refrigerators, etc.) consume significantly more energy at startup than during regular operation. For such loads, it's important to check the peak power of the inverter (see the relevant paragraph) — it should be higher than the starting power of the load.
Rated power
The rated output power of the inverter, expressed in watts (W).
This parameter means the power that the device can provide to consumers for an unlimited time. It is necessary to choose according to this indicator so that the rated power of the inverter covers the power consumption of the expected load by approximately 15-20%. It is also worth considering that some electrical appliances (in particular, units with electric motors - vacuum cleaners, refrigerators, etc.) consume significantly more energy when starting up than after entering the mode. For such a load, it is also necessary to clarify the peak power of the inverter (see the corresponding paragraph) - it should be higher than the starting power of the load.
Peak power
The highest total output power in watts (W) that the inverter can deliver to a load for a relatively short period of time, on the order of 2 to 3 seconds. As a rule, this power is 30 - 50% more than the rated power (see above). The peak load value can be useful when calculating how the inverter works together with appliances that consume a lot of energy at start-up (vacuum cleaners, borehole pumps, power tools, etc.). The rule here is simple - the peak power of the inverter must not be lower than the starting power of the load.
Rated AC current
The current strength that the device is capable of stably and safely delivering when operating in rated mode (i.e. for the longest possible time without the risk of overloads and failures). The indicator is expressed in Amperes (A).
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.
Functions
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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).
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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.
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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.
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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.
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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.
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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.
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USB. A standard USB port is often used for configuring equipment via a wired connection to a computer or for inverter firmware updates.
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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.
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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.
