Using battery power to go off the City's power grid

Since I'm more familiar with the UPS world, from experience, standard UPS' (themselves) will give off a mechanical hum, and most always a fan will kick on, when a loss of power is detected and they are called for action. but I've never heard any mechanical clicks emanating from them. Double-conversion UPS's (since they're always on battery power) will typically *always* emit some hum and fan noise, continuously (fans to keep the batteries and inverter circuitry cool). That's why I try to locate them away from quiet recording/broadcast studios, or my personal listening areas. I never hear any mechanical clicking noises emanating from them either. Not sure how many audiophiles use UPS' though.   

I never heard any hums, clicks when charging and listening with N.E.W amp, Merlin BAM or Rockpals battery pack on dac and different streaming equipment lps. Fan would be on with the Rockpals.

Shifting gears, I want to ask the Bluetti or other battery/inverter owners whether they tried these units on complete systems including power amps, as well as just for the low power front end components.  My theory is that the AC powerline distortions are relatively small compared to the main signal, and they would be a much higher fraction for low power components.  It is likely that the entire system would benefit, but my guess is that most of the benefits would be just using the low powered components on the inverter.

@dpop 

Both actually. I have a ups on my cable modem, router and computers and it was the worst! When charging it hums and put out a hum on my Node N130 that I could easily hear.  My wife has a small battery backup, (forget the brand) and it was whisper quiet until it decided to charge and then there were some clicks, but no hum. To bad it only lasted about 90 minutes before the charger kicked on.

@sbayne 

I’ll check out the Bluetti Max series.

Thanks.