Hi, I have a 12V system with a phoenix 375 inverter that powers very low charges (internet modem and wifi + a radio). I can hear a clickin/huming noise coming from the unit. It has a frequency of about 2 hertz. It also is visible to my 12v led lights systems. It does it regardless of the battery charge level. The firmware is up to date. My cheap backup inverter does not have the same effect... the noise is not that bad but the flickering effect on the lights it not tolerable.
is this normal or my unit (3 weeks old) might be defect?