It will run off a battery for a bit but not for very long, the LEDs draw a fair bit of power, especially when you start lighting up a lot of them. To protect the circuitry and to run it directly off a USB port I reduced the brightness to a maximum of 16 out of 256, that seems to work fine but when all of the LEDs are illuminated you can sometimes see a bit of a ripple when it is on a small charger.

These LEDs put out an insane amount of light at full illumination, they do a about 50 mA each so if you were to set all of them to 'white' and maximum intensity (255,255,255) then that would work out to 1536x.05A or a whopping 75A. You'd need a very beefy power supply to be able to do that and you'd need to power each of the LED boards separately (they already have leads soldered on for that purpose but I left those unconnected for now).

At 5V power consumption would be 375W, and I reckon the boards would get fairly hot, each LED would do .250 W.

So for practical reasons I think limiting the intensity is a smart move, unless you know for sure that you will be illuminating only very few LEDs.