Comparison Qoltec 53875 vs Axioma ISMPPT BF 1200

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.

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.

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.

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.

The operating range of the inverter is usually located between the starting voltage and the maximum voltage. This interval is indicated in volts.

Built-in Maximum Power Point Tracking (MPPT) system for monitoring the maximum power points of photovoltaic modules in solar panels. It determines the most optimal ratio of voltage and current drawn from the solar panels, thereby ensuring maximum performance of individual strings (chains of series-connected panels). An MPPT controller is useful under any external weather changes, allowing solar panels to generate power even in cloudy conditions. Modern inverter models can contain either one or several MPPT trackers (up to six), which allow for the connection of multiple arrays with different orientations and angles of inclination, thereby eliminating the mutual influence of one array on another. Each MPPT controller output is designed to connect one string.

Strings in solar energy are chains of panels connected in series. With this connection method, the voltage of the solar panels is summed up, and the current remains constant, which allows you to significantly increase the power generation capacity while maintaining a fairly low current and without the need to use large-section wires.

Specifically, this paragraph indicates the maximum number of strings that can be connected to the inverter for solar panels.

— 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.

A method of removing heat from the heating elements of the inverter.

— Passive cooling. Passive is any type of cooling that does not involve forced heat removal and is carried out through natural heat transfer and convection. Its main advantage is the complete absence of noise. In addition, such devices are cheaper, do not consume energy to operate the cooling system, and take up relatively little space. On the other hand, passive cooling is significantly inferior to active cooling in terms of efficiency, and therefore is poorly suited for powerful devices.

— Active cooling (fans). Active cooling involves the forced removal of heat from device components through radiators with fans that “blow away” excess heat outside the case. Such systems are characterized by extremely high efficiency and can be used in inverters of any power. However, you will have to put up with increased noise levels, as well as significant dimensions and weight of the equipment. In addition, fans tend to draw dust into the case, and if they break down, the entire cooling system essentially fails. The cost of inverters with active cooling is significantly higher than models with a passive principle of heat removal from internal components.