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.
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.
Maximum charge current
The maximum amount of direct current in amperes that the inverter can convert. If the solar panel produces a current exceeding this value, the inverter simply does not use it. This is often justified when connecting an inverter to high-power solar panels - the maximum input current of the inverter is reduced to acceptable values so that moderate-sized wires can be used to transmit energy.
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.
Protection
—
Overload protection. A protection system against connecting an off-design load whose power consumption exceeds the capabilities of the inverter for solar panels. In such situations, the power to the outlets is automatically turned off, since overloading the device promises failure and even fire. Triggering of the protection is usually accompanied by a sound and/or light signal.
—
Overheat protection. This protection is triggered when the temperature inside the inverter rises critically. When such situations occur, the device turns off, which avoids breakdowns. In the future, some models will automatically turn on when the temperature normalizes, while others must be turned on manually. Note that overheating is caused not only by malfunctions, but also by completely normal reasons - for example, long-term operation at high air temperatures. Typically, overheating protection is accompanied by a sound and/or light signal.
—
Protection against ↑ or ↓ battery voltage. A protection system that prevents the inverter from being supplied with excessively high or excessively low voltage from the batteries. When the operating voltage range is exceeded, the device automatically turns off to avoid breakdowns and other troubles. A sound and/or light signal can warn of protection activation.
—
Short circuit protection. Protec
...tion that is triggered when the output current increases critically (for example, due to a foreign metal object getting between live parts of the load). To avoid breakdowns and failure, the power at the inverter output is automatically turned off. Triggering of the protection system is usually accompanied by a sound and/or light signal.
— Reverse polarity protection. Protection system in case of incorrect polarity of connection. If the “plus” and “minus” do not match, the inverter is disconnected from the power supply in order to avoid damage to the electronic components. Notification of protection activation is often provided by a sound and/or light signal.
— Protection class. The class of protection against dust and moisture provided by the inverter housing for solar panels. Indicated according to the IP standard by two numbers: the first (from 1 to 6) means resistance to penetration of foreign objects and dust, the second (from 1 to 8) - protection from moisture. The higher the number, the higher the level of protection provided. Also note that instead of the first digit in the designation of the protection class, “X” may be indicated - for example, IPX7. In this case, the device is not certified for dust protection, although in fact the level of such protection may be quite high. So, in the example with moisture resistance “7”, the case can be completely immersed in water - which means it is closed very tightly from dust.
The IP protection level is especially important to consider when choosing models for outdoor use and installation in rooms with high humidity levels - they are the ones most susceptible to adverse environmental influences. A high IP class will guarantee stable operation of the inverter for solar panels in such difficult conditions.