Dessicant dehumidifier?
Suprisingly, google isn't turning up much useful stuff on this one.
I know a number of people use these, based on silica gel or similar, inside the aircraft.
Mine is hangared but I know it actually spends quite a bit of time outside during the day, and I want to make the avionics last as long as possible.
There are various small mains powered refrigeration-cycle-based units but I can't easily ensure that a 240V supply is connected. So something with a replaceable "pack" would be great.
Aircraft Spruce sells something that has 110V power input and goes into the dipstick hole. I don't need that because I fly at least once a week. I am after something that can sit on the floor.
Any suggestions?