AC200MAX the squeaking(ultrasound) when the AC output is turned on

Hi all
I bought a brand new AC200MAX and heard the squeaking(ultrasound) when the AC output turned on. The sound is exactly the same with load or without. When I’m using only DC to charge mobile devices that issue is not reproduced.

The question is - it is expected behavior or do I need to contact the seller to replace the device?


@Oleks What device did you load with? Could you please record the sound so we can check if there is a problem?

@BLUETTI_CARE It was without the load. Also, it is the same when under load by a PC or mobile phone charger (from 10w to 500w)
Video here: iCloud
sound after 10 seconds.

I’ve returned back to the seller and got another - it also has some noise, but not too loud as in this video.

@Oleks Sorry I couldn’t hear the sound exactly from the video. Is there other things placed next to AC200MAX? It is suspected that electromagnetic waves may interfere with the machine.

@BLUETTI_CARE it was stand-alone. I’ve replaced the device with the seller and the new one is silent as expected. The sound was sometimes hard to hear from the recording, but it was definitely when you were next to the station.

@Oleks That’s great. I’m glad that your problem has been solved.