It doesn't make any sense, a battery will be lower noise and impedance if chosen correctly. use one or the other, but using battery to power a psu is just throwing away stored energy in un-required stages of further regulation. Been there, done that, measured it, moved back to a good regulated supply.
Kuzma Stabi/S 12", (LP12-bastard) DC motor and optical tacho psu, Benz LP, Paradise (phonostage). Imac m1, gustard A18dac, Bruno Putzeys balanced pre, neurochrome 486 dual mono amps, Yamaha NS1000m with raal ribbons