Annoying PWM sound from Xantrex inverter

CA Traveler wrote:

Do you mean it's in standby so it's not off?

I mean it is as off as this inverter can be, without actually disconnecting the DC inputs. The power button is an instantaneous button and you push it to turn the unit on and off. No doubt this means that even when "off" there is a microscopic draw to support detecting the button push (there is also a remote option).

So I'm not sure if thats' what you mean by "standby" or not - I'm definitely not talking about a state where it's ready to turn on when it detects an AC load.

FYI Pulsed type of power has a large number and frequency of power transients and can cause various symptoms, especially the way yours is wired.

Interesting. So there is the possibility that the PWM induced transients cause this issue, but it seems also that even ignoring the transients, the PWM itself will cause current flow to cycle on and off rapidly, and this may induce some voltage changes in the wiring?

It helps to have a controller with battery voltage sense capability however.

Helps with this kind of noise issue, or helps in general? Is this a separate set of leads (distinct from the charging ones) that allow the controller to read the voltage? How would it differ from the voltage the controller sees on its charge output? ISTM they would only differ by the voltage drop along the charging wires (which in my case is very small as they are a couple feet long at the current I get from my panels is moderate).