Can you feed a solar controller from a charger AND solar?

Fan cooled, 1 600-watt DC to DC booster is interesting. With a single DPDT relay and a 12-volt interval timer like the OMRON I posted here a week ago, when the batteries charge by set timer enough to reach 13.6 volts the timer kicks the relay which energizes the booster. Play with booster voltage and time at booster max set point, then the timer shuts off and reverts to 13.6. This critter can be bread boarded on a little piece of plywood. Or do it with an AC timer or use a MegaWatt. The world is your oyster.