GX3 battery power

[sixtiesman]

Oh joy of joys, my Anker 10000mAh costing 17.99 from Amazon will power the GX3 for at least 20 hours!

I have a microcube which runs on 9v......I'm wondering if I can run two power packs ( ie 10v in series ) and drop the voltage to 9v with a voltage regulator ( £2.98 from ebay ).

My phone will play the UB Hank backing tracks into the roland cube...............

Does anybody know if the roland has a voltage regulator built in? I could just series two power packs at 10v and run the cube all day!?

regards

sixtiesman