Portable controller for use with Cross DJ on android?

[zubind]

Hi there, I'm a complete newbie to the world of DJing. I've installed CrossDJ on my android tablet, and I'm using it with a portable battery operated speaker. The places I'm DJing, there is no ac power and no generators, so everything has to be battery powered. I would like to couple this setup with a hardware DJ controller that is portable (runs off battery power or usb), and be able to use headphones to cue. Is there a hardware controller I can buy which will work in this kind of setup?
Thanks!

[RoJeC]

Running of battery power only is pretty risky. The normal setup is to connect both tab as controller to a powered usb hub. Tabs aren't really designed to provide power to external devices.

Only thing I can suggest is to use an usb hub and connect a serious powerbank to it. Maybe start with cheap small one to check if it works.

[zubind]

Thanks RoJec for your reply. I was not planning to run the controller off the tablet's power. I just wanted a controller I can run off an external battery. So in other words, I'm looking for a hardware controller that works with Cross DJ and which does not require A/C power (i.e., it gets its power either from an internal battery, or from external USB power source, eg an external USB battery pack). So which controller would you recommend I buy that would meet these requirements?
Thanks again!

[RoJeC]

Powerbank = usb battery pack.
All supported controllers for Android run on one usb power outlet. So the battery pack should be capable of loading/using both devices.