I have been TRL SS mono amps with battery power, M250 (250W) and M500(500W) for over a year. The huge ~200 lb battery chassis ensures the instant, ample, and sufficient current can be supplied on demand, especially while playing back a dynamic piece of large scale orchestral work. The amps enable the system to playback with the transparency, transient, weight, density, and dynamic that surpass my previous amps such as Krell KAS2 and Pass x250, and many other top amps owned by and heard at friends. To my knowledge, the battery pack serves as a current reservoir/buffer, therefore the batteries are being recharged while in use. Because of that, there is no usage limitation. I often have the system on for two or three days during the weekend. I usually just leave the amps on and only turn them off and back on when I need to turn on my tube pre.