We have a solar system in our Airstream trailer installed by an AM Solar dealer. Lately after we get to our next site and hook up to shore power, there is a loud hum coming from the Victron Multiplus 12/3000/120 inverter as it works to top off the batteries. The hum only lasts for a short while and stops once the system achieves "absorption" I think.
Any ideas of what I can check and whether or not this is something serious?
Thanks