Pearl on batteries?

I found some threads asking about this. Has anyone done this? What batteries did you use, how many, and where did you bring them into the circuit (i.e. did you leave out any part of the power supply circuit)? What are your listening impressions when compared to an AC supply? And finally, what are you doing to charge them? How long does it take to charge, how long do the batteries last before they need recharge (which depends on the Ah rating, so the question really should be, how much current does the Pearl draw)?