(I’m just rehearsing how to sell my own product)

Instead of buying switching power supplies (or switch-mode power supplies) for radio transceivers i rig my own out from an ordinary battery charger that i’ve improvised to operate on automatic during charging operations that will also provide an auxiliary 18-volt DC source, the voltage of which must pass through an LC ripple filter to screen out the 60-hertz humming especially during the transmit mode and then to the 13.8-volt regulation stage to give the necessary voltage level for the transceiver.

Most commercially available switching power supplies can operate only to provide the regulated 13.8-volt source but cannot at the same time operate as battery chargers due to high continuous current required in the charging operation. My rigged setup can perform said dual tasks and with an addition of automatic transfer switch can serve the automatic power requirements of radio repeaters.
(I don’t mind my friend called me old school)