Normally, a balcony power plant must switch off immediately in the event of a power failure. Otherwise, it is possible to get an electric shock. However, after the Growatt inverter was switched off, the measured voltage of the test unit doubled from the household-standard 230 to 460 volts.
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In addition, the inverter took 0.7 seconds to switch off. That sounds like little, but the Association for Electrical, Electronic & Information Technologies (VDE) specifies 0.2 seconds in the standard that is decisive for certification.
Other MIC 600TL-X units confirm faults
The magazine Computer Bild now tested in the test laboratory whether the promised standards are actually adhered to for inverters. Result: According to this, the MIC 600TL-X inverter from Growatt harbours potential risks. To verify the anomalies, Computer Bild bought three more Growatt MIC 600TL-Xs. Besides the first one, another inverter switched off too slowly. It also took about 0.7 seconds, in the worst case it was 0.9 seconds. And: In all devices, the voltage rose to values between 360 and 460 volts - significantly more than the usual household mains voltage.
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The VDE explained that household appliances generally tolerate voltage fluctuations of ten percent without damage. If more is fed in by a producer, it can lead to defects in devices connected in the same circuit. This was the case with the tested Growatt inverters. Whether the inverter may remain connected to the grid must now be clarified by the authorities. The inverter in question could lose its operating licence. (nhp/mfo)
