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 output power
The inverter's rated output power, expressed in volt-amperes (VA). This is essentially the same as power 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.
Output current
The maximum current in amperes (A) that the inverter, when operating, is capable of outputting without overloads or failures.
Output voltage waveform
The shape that the voltage graph given 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.
Battery 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.Max. input 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.
Operating voltage range
The operating range of the inverter is usually located between the starting voltage and the maximum voltage. This interval is indicated in volts.
Max. 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.
