I have the battery power supply for the Pre-1.5 preamp. I hope to some day get the battery power supply for the D-225 amp I have. In the preamp the batteries are housed within an ST-225 chassis. So that is convenient. The preamp is biased for Class A operation and if I recall runs at about 44 volts. In order to maintain a constant 44 volts the battery needs to be run in trickle charge mode. You can run it on complete battery mode but as the voltage drops and the bias moves from Class A down so does the sound quality, but it is still quite listenable. Bass becomes a bit more flubby for one thing.
I'm amazed at the transparency and detail of the TRL combination. At the same time it is extremely musical. In the right listening room the soundstage is huge, but not exaggerated like in some systems I have heard. The amp can handle any speaker load effortlessly. It never runs hot and the power supply is way overbuilt. I plug it straight into the wall now and it is dead quiet. I have tested it on a number of occasions with the inputs shorted and speakers connected. No hiss, hum, not a peep.