Even with only 20 - 25 hours the Monica II sounds real nice. It is smooth, warm, tubey sounding. Very sweet and moist.
The dynamics and frequency extremes are rolled compared to my modified Marantz player. This may change with more hours.
I am using a pair of the 12 volt, 2.3 Ah batteries Walmart clearanced for 5.00. One for the analog, and one for the digital.
The two leds used draw more power than the Monica. It should run for 10 - 12 hours at least between charges.