High pitched, high frequency buzzing/noise

[kitestrings]

Hi Folks,

I've noticed at certain times there is an audible high pitch, high frequency noise coming from the Classics.  I usually notice it when the battery voltage is getting up near the absorb set-point, and similarly when I've had to charge using the inverter charger (and auxiliary generator).  I assume this is normal, but I wanted to check.

I also wanted to be sure there is no conflict of interest if I'm charging with the inverter charger and we're still in the (normal) "wind" mode.  this case when we get to 59-60V it would seem the Classic may 'see' the input voltage as the RE source.  With the solar CC (Outback MS60) we normally turn off the diversion load(s), but otherwise no change.  We don't need to turn the Classic's Mode to "off" or something I'm overlooking?

Thanks for any input.  ~kitestrings

[dgd]

I've noticed at certain times there is an audible high pitch, high frequency noise coming from the Classics.  I usually notice it when the battery voltage is getting up near the absorb set-point, and similarly when I've had to charge using the inverter charger (and auxiliary generator).  I assume this is normal, but I wanted to check.

One of my three Classic makes this high frequency 'singing' on a fairly regular basis. It the oldest Classic I have #879. It has always done this especially when its under load and pushing out 80A+ into the battery bank at just under absorb voltage.
Since its been doing this for near 2 years now it seems nothing to be concerned about. The Classic works nicely and its sort of reassuring that I hear this when I get near my power wall because it means my hearing is still working too 

My other Classics, a 250 and 150 lite are both always silent (to me). I sometimes wish they would sing too.. - perhaps there is a modbus singing register that could be set 

dgd

[cybermaus]

If you mean the high pitched singing that I thing you do, then its typically either capacitors or inductors.

Especially on older equipment and if it was not so in the beginning, it may be because the electrolytic capacitors are starting to evaporate and may fail soon. For inductors it is more stable (does not get worse over time) and does not indicate any problem other than being annoying. 

I trust Midnite Solar is using the good (Japanese) brand capacitors and not the now infamous Chinese knockoffs that caused Dell and others so much problems previous decade?

[boB]

Go into tweaks and turn off LMX  (Low Max)

That'll probably stop  it from singing.

boB

[RossW]

Go into tweaks and turn off LMX  (Low Max)

That'll probably stop  it from singing.

Go fire off 5000 rounds of 7.62mm without PPE.
I doubt the singing will bug you after. (Mine doesn't!)

[TomW]

Go fire off 5000 rounds of 7.62mm without PPE.
I doubt the singing will bug you after. (Mine doesn't!)

+1

[kitestrings]

I take it from the tone of the responses that's it's nothing to worry about.

Ross's response reminds me of a familiar response I give my wife when she says the car is making a strange noise, which I like to have her repeat as though I don't hear it right the first few times (until she hits me) ..."can you turn up the radio"?

I've 'tweaked' the LMX settings to off, and we'll see what happens, but Low Max sounds like when, in PV application, the array voltage is near the battery voltage.  When I notice this singing, it is usually when the batteries are pretty well up, and I'd assume the input source (though I haven't noted this for sure).

Thanks for the help, ~kitestrings