What are you using the RD for or on?
One method is to park two motorcycle 12v batts in series under desk, send 24vdc to the RD.
Then just attache a small "smart" batt-tainer to each batt, turn on the charging when you not using the RD.
The dc-dc warts are gonna be noisy, but you can perhaps tack on a fat cap to the dc input of the RD, and add a few twists of the supply lines around some iron.