Comparison Marstek Venus D vs Marstek Venus A

The nominal power in kVA shows the total electrical load that an inverter can handle in terms of voltage and current, taking into account the characteristics of the connected devices. This parameter is especially important for equipment with motors, transformers, compressors, and other reactive loads, where consumption does not always equal useful power in kW.

kVA should not be directly equated to kW: at a power factor of 0.8, a 5 kVA device is actually designed for approximately 4 kW of active load. For example, a pump, air conditioner, or refrigeration compressor may load the inverter more in kVA terms than it seems based on their usual power in watts.

The rated power in kW indicates the active load that an inverter or controller can reliably handle in operational mode. This value is closest to the actual consumption of household appliances such as refrigerators, pumps, boilers, lighting, and power tools.

Unlike peak power, the rated power is not calculated for short bursts, but for prolonged operation without overheating and overloading. For example, a 5 kW inverter can supply several devices with a total continuous consumption up to this level, but for a motor or pump, it is advisable to leave a margin for the starting current.

The maximum active load that the inverter can withstand briefly, usually during the startup of equipment. This reserve is needed for devices with a high starting current: pumps, refrigerators, compressors, power tools.

Unlike nominal power, peak power is not designed for continuous operation and lasts only a few seconds or even fractions of a second. For example, an inverter with a nominal power of 5 kW and a peak power of 10 kW can briefly handle the startup of a pump, but it should not continuously supply a load of 10 kW.

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).

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.

The total capacity of the connected batteries in watt-hours (Wh). In fact, this is the amount of energy that is supposed to be stored in the battery. The larger the capacity, the longer the battery life of the connected equipment will be, all other things being equal. On the other hand, this parameter also affects the dimensions, weight and price of the battery. Based on the capacity in watt-hours, batteries can be compared with each other.

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.

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.

Connection interfaces provided in the inverter design for solar panels.

- 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.

- 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.

- USB. A standard USB port is often used for configuring equipment via a wired connection to a computer or for inverter firmware updates.

- 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.

- 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.