a real answer to your question...
Connector on the right
the ac adapter that works with your OI can be wired (DO N0T OPEN IT) to plug to your RC +12v and Ground the inside part of the adapter is your +12v and your outer conection is ground. should be more than enough to keep your rc on and all that nice stuff.
a stiff 18 awg wire can be inserted in the inside of the coonector housing and taped there , and the out conector can be rig with a 18 awg wraped around and tapes in place or u can get aligator clips or just have someone holdng this adapter.
you can jump start the rc unit with this method and disconnect and leave your back up battery powering.
WARNING do not power more then just the RC like this.