Hi, I have a brand new Victron 150V 70A charge controller and when charging it emits a really annoying high pitched noise. The frequency of the sound is 18kHz, tested using an audio spectrum analyser app, is this normal, is my unit defective? I also have a 250v 100a mppt from victron and it is dead silent. Should the 150 70 have a mosfet switching frequency of only 18khz? It seems too low as some sensitive people can still hear at this frequency. Also, does the 250 100a mppt have a higher switching frequency?, if so thats probably the reason it is silent.
