Back in the day I had N.E.W. (Nirvana Electronic Werkes) class a SS amp that ran off 4 wheelchair 12V batteries. My Merlin VSM BAM runs off four 9V batteries. I've tried various battery packs/inverters to run some source equipment. There is a certain level of the black background/noise floors thing even conditioned AC can't compete with.
To Battery Or Not To Battery (12 Volt)
https://www.youtube.com/watch?v=4sEvxjdLW-o
Jay's Audio Lab interviews Danny from GR Research about Danny's 12 volt battery power setup. I am not going to pay for a $17,000.00 Stromtank, but the discussed battery arrangement looks more doable though I would prefer it in kit form which Danny just might want to do though the liability costs might be prohibitive.