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.
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.
Output waveform
The form that the graph of the voltage produced by the inverter has.
This can be
a pure sinusoid with a high quality output signal - the voltage on the graph changes evenly, without sudden jumps and drops. It is as close as possible to the parameters of conventional sockets. Models with pure sine wave voltage allow you to connect almost any load - even delicate electronics that are sensitive to power quality. On the other hand, such quality requires the use of complex control circuits and significantly affects the cost of the inverter, and there is not always a real need for it.
Another option for the output signal shape is a modified (approximated) sine wave. As a rule, such graphs are constructed from stepped lines, sometimes quite large. The disadvantage of the modified sine is the inability to work with sensitive equipment (for example, where asynchronous motors or transformers are installed). However, in the absence of such a need, this moment cannot be called critical.
Number of sockets
The number of standard 230 V sockets provided in the inverter design.
The more
sockets there are, the more electrical appliances can be connected to the inverter at once. At the same time, the specificity of using inverters is such that they rarely have to be used for several devices at once. In addition, simultaneous connection requires appropriate power (see “Rated output power”), and the sockets themselves also significantly affect the dimensions. Therefore, most often in modern home inverters one socket is used – this, usually, is enough. However, high-quality powerful inverters can have two sockets.
Connection voltage
The efficiency of the solar system, laid down by the manufacturer of the inverter, directly depends on this parameter. The following battery voltage options are most widely used:
12 V,
24 V and
48 V.Number of battery inputs
Number of points for connecting batteries to the inverter. Household models usually have one such input, while powerful and productive models may have two or even three battery inputs. Multiple inputs allow the system to be scaled by adding batteries without having to replace the inverter.
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.
