Solar charge controller making high pitch humming sound when idle

[Jake123]

So I have a Epever Triron 40 amp charge controller and whenever there is no power coming into the unit from the solar panels and the outgoing power (2 usb ports) from the charge controller isn’t on, it makes the high pitch humming sound, basically when power isn’t going into the unit or going out of the unit it makes the sound, in other words: when it’s idle.
Is this normal? because when I go to sleep I have to turn on the power and let it burn a small amount of watts for it not to make noise..
Or is the unit faulty?

 

[rhino]

Is it a PWM type controller? They also have this: https://www.epever.com/bwl-advanced...oise-when-the-battery-is-nearly-getting-full/

For reference my Victron charge controllers are dead silent no matter what they are doing.

 

[Jake123]

Is it a PWM type controller? They also have this: https://www.epever.com/bwl-advanced...oise-when-the-battery-is-nearly-getting-full/

For reference my Victron charge controllers are dead silent no matter what they are doing.

No, It’s an MPPT controller

 

[Bossrox]

I'm using growatt chargers & they do the same thing, it's not very loud tho & normal I guess 'cuz they work just fine all the time. I've tried epever gear but they don't hold up very well.

 

[Jake123]

I also do have a strange problem with charging, sometimes the solar panels won’t charge unless I turn it on and off and it starts working normally and the thing is the charge controller recognizes there’s power because it says the voltage but it won’t accept power until I turn the breaker off then back on.. it can sit like that for days and not charge until I reset the breaker (can’t be the breaker because before and after resetting the breaker, the charge controller still sees the voltage from the panels coming in)

 

[parkerd]

I also do have a strange problem with charging, sometimes the solar panels won’t charge unless I turn it on and off and it starts working normally and the thing is the charge controller recognizes there’s power because it says the voltage but it won’t accept power until I turn the breaker off then back on.. it can sit like that for days and not charge until I reset the breaker (can’t be the breaker because before and after resetting the breaker, the charge controller still sees the voltage from the panels coming in)

Sometimes if im away from house and i see this going on i turn House AC on and that draw corrects it. Weird

 

[parkerd]

Sometimes if im away from house and i see this going on i turn House AC on and that draw corrects it. Weird

Also i found lose mc4 connector