The Easun Power ISolar-SMX-II series consists of off-grid (battery inverter) systems designed for use in island systems and as backup power in UPS mode. These units feature a pure sine wave, ensuring safe operation with sensitive electronics and motor-driven devices, along with comprehensive priority power supply modes (PV-grid-battery), optimizing self-consumption.
Depending on the variant, the series supports parallel operation, enabling the scaling of installations in homes with high energy consumption or small commercial premises. The integrated MPPT tracker enhances energy harvesting in variable conditions, particularly when panels operate at different angles or experience partial shading.
High efficiency under European operating conditions translates to significantly better yields in Poland's typical climate. Remote monitoring via Wi-Fi and service communication (e.g., RS485/USB) facilitate diagnostics and production control. The ISolar-SMX-II is compatible with popular energy storage systems, including LiFePO4, and its safety is supported by CE certification and manufacturer's warranty.
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Pros and cons
A THD (Total Harmonic Distortion) of less than 3% allows for the safe powering of sensitive electronics (e.g., appliances with inverters, medical equipment, and pumps with induction motors), which is not guaranteed by cheaper quasi-sinusoidal inverters that are common in this price range.
The 5.6 kW MPPT tracker achieves 80 A with a PV voltage range of approximately 145 V DC, enabling the connection of 2-3 panel strings without an external charger controller - this reduces the cost and complexity of off-grid installations.
The series supports parallel connections: 2 devices in a single-phase system (~11 kW), 3 in a three-phase system (~16.5 kW), or up to 6 in a split-phase system (~33 kW). This allows for phased expansion of the installation without replacing the inverter.
Wireless WiFi communication and RS485 and USB interfaces are available without additional charges (unlike competitors such as Victron, where GSM/WiFi monitoring requires the purchase of additional modules costing 200-400 zł).
The user can manually set absorption voltages, float voltage, and equalization, ensuring proper compatibility with LiFePO4, AGM, and gel batteries without the need for an external BMS interface.
The ISolar-SMX-II was introduced in 2021 and is now marked as discontinued. This means that the availability of original spare parts (control boards, capacitors, IGBT modules) is limited, and there are no firmware updates available - the risk increases with failures after the warranty period has expired.
Users on the DIY Solar Power Forum report increased standby power consumption as a significant issue in isolated systems during winter, when the availability of solar power is low. For comparison, Victron MultiPlus-II inverters claim a standby power consumption of around 14-20 W, compared to the higher values reported for the SMX II.
Numerous reviews on Trustpilot and forum threads (DIY Solar Power Forum, elektroda.pl) indicate a lack of response from the company after reporting a fault, repeated failure to fulfill promises of replacing components, and a cessation of responding to emails. While the warranty is formally 3 years, its enforcement is uncertain for customers outside the Chinese market.
Easun Power (founded in 2006, China) operates under an OEM-reseller model: devices are manufactured by external suppliers and rebranded. This reduces the predictability of quality control and makes it difficult to identify the actual manufacturer of the components in the event of serious malfunctions.
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About the ISolar-SMX-II series
These answers cover the whole series. Where a figure differs, the specification above is this model's own.