I am using a AC/DC power adapter to supply 12V to mini-ITX board, now I am trying to order Nie-battery group with 12V/4500MAH output to supply my computer, the problem is there is no voltage control module to ensure stable 12V output from the battery group, if battery output 10V or 13V to my computer this does not work for me. Does anybody know how to solve this problem? The stable and small power supply unit is critical for my computer.