Second Chance Gemini 3400
This project was necessary due to the overwhelming heat that
builds up because of all the windows and the lack of insulation
within the Gemini. The small black cube in the picture is a timer
variable from 1 to 5 min available from Grainger. ( www.grainger.com)
the white box to the right is the 20 amp relay also from Grainger used to switch
the AC on. The input to the relay is wired directly from the bus, to a circuit breaker
to the common side of the relay. The power is then wired to the air conditioner main
power supply. The timer cube is wired to a temperature sensor mounted in the
air conditioning box in the main cabin.
When the temperature reached the set limit, The Air Conditioner is supplied with power.
If the main Air Conditoner switch is on, (Not the Breaker ), the unit will come on and run
until the set point is reached. I keep the set point at 90 degrees F. The timer prevents
the compressor from short cyclying and burning up. When we are on the boat, I turn the main
circuit breaker for the air conditioner on and it operates normally using the original
thermostat for temperature regulation.
For colder climates, a low set point switch could be installed so that if the temperature
fell below a certain point, the main air conditioner / heater would come on and warm
I have found this invaluable in the warm georgia sun when the boat is docked. The interior of
the boat would easily exceed 130 degrees F. That kind of heat dries out the wood, causes the
glue that holds the headliner up to fail and other damage. Also, the refrigerator runs alot better
when the interior of the boat is not so hot.
The timer cube and relay were later relocated, still within the electrical area, when the generator
was installed. The switch between generator and shore power is now located there so it can be reached
from outside the berth.