The Strom Mobile transforms the output voltage of USB power banks (5V DC) to either 9V or 12V DC to power any (music) device running on those voltages. There are two independent channels which can output individually set voltages. The Strom Mobile includes an input current feedback system to save the user from exceeding the maximum output current of the USB powerbank in use.
Searching for “laptop powerbank” will get ones that output various/higher voltages. Something like this:
which can output 16V or 20V should work with supplies like uZeus, 4MS Row Power, or Intellijel’s. It’s hard to reccomend a power supply without knowing what kind of case you’re intending to use or your overall power draw.
I really am not sure what you’re cooking up here. I thought I’d call your attention to this post before you buy a uZeus for use with the ER-301. Not sure if it’s applicable or not but please have a read first. That way you’ll be informed if there is a potential issue.