12 volt fridge fan for RV

Discussion in 'The Projects Forum' started by Dodaman, Jun 15, 2016.

  1. Dodaman

    Thread Starter New Member

    Jun 15, 2016
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    Hello,

    Let me start by saying thanks for having this forum. I have posted this question on a few RV forums, but no one has been able to help. I installed a 4" computer fan behind, or outside, my small fridge in my RV. It's an absorption fridge and helping to remove the heat on hot days improves the cooling on the inside.

    I have tied it into the 12v power and put an inline fuse and thermostat on It. I also added a on/off switch. It works great when it is hot outside. But on the days when the thermostat doesn't kick on, about 130 degrees, the fridge still needs a bit of help cooling inside. I can certainly bypass the thermostat and have it run all the time. But what I would like to do is install a new switch, so one way runs it all the time, and the other way runs it through the thermostat like currently.

    I have been trying to figure out how to do this. Would a spdt switch with a center off work for this? And if so, how exactly would I go about wiring this. Thank you all for your responses. Take care,

    Mark
     
  2. #12

    Expert

    Nov 30, 2010
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    Ten characters.....
     
  3. Dodaman

    Thread Starter New Member

    Jun 15, 2016
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    Thank you for your reply. Just to confirm a few things. So I have the right idea about which switch to use, spdt?

    I assume I will use an inline fuse for both sides, and I put them after the thermostat and direct power line before the switch. Or just put one inline fuse after the switch before the fan?

    Thank you so much.
     
  4. #12

    Expert

    Nov 30, 2010
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    One fuse after the switch...or before the thermostat and the 12 volt line...or in the ground line of the fan.
    I made the drawing for the switch you described. I don't know why you would want to doubt it now. You said SPST center off. That's what I drew.
    If you want to change the switch, the drawing might have to change.
     
  5. Dodaman

    Thread Starter New Member

    Jun 15, 2016
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    Oh dude. I don't doubt you. I thank you for your drawing. It just created more questions. That's all. Besides, just following direction. I like to actually learn and understand what I'm doing. Hence, the extra questions. No disrespect.

    I understand the fuse part, with regards to the switch, I bought a single pole double throw switch, it looks like this is the switch you drew, but You wrote above SPST. Just want to confirm. I can build a engine or a garage blindfolded, but this circuit stuff doesn't come easy to me. And I don't want mess t up, so there is a fire hazard.
    I really appreciate your help.
    Thanks. Mark
     
  6. Dodaman

    Thread Starter New Member

    Jun 15, 2016
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    Ok, I am sorry man, but I just was looking over the diagram again, I'm confused, if this diagram is for a SPDT switch, it has 3 prongs coming from it. The one your drew has 4 contacts.

    Please bare with me. If I understand what you wrote, instead of bringing power into the on/off switch I have currently and then going out to the thermostat and then to switch, I will need to bring one power line to the thermostat to one side if the switch. Then run a second power line directly to the other side of the switch. I assume the middle spade, (or whatever is the correct term) is for the common ground line? But how do I run then run the switch to the fan? This is what I am not seeing. Again, my apologies for the novice questions, but I'm not getting what you draw if we are speaking of a SPDT switch with 3 prongs off it. Thank you.

    If that is the case, then how do I tie
     
  7. #12

    Expert

    Nov 30, 2010
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    That switch in the drawing is the most similar of what I had in my image library. The extra connector in the drawing (which is not connected) represents the center-off position which is not presented as a connector on your switch and is not connected to anything. Just erase the symbol for center off. There I did it. Does that work now?
     
  8. Dodaman

    Thread Starter New Member

    Jun 15, 2016
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    I think so. Indulge me please and just answer my last questions to make sure I am getting this.. Sorry for this, but the questions stem more from what I don't see in your diagram.

    1. So I run 2 wires from the main 12 v positive. One for the thermostat and the other direct. Both of these go to the switch.
    2. The common plug on the switch gets the red positive wire from the fan.
    3. The ground wire from the fan goes to the 12 volt ground.

    Did I get it ?.
     
  9. #12

    Expert

    Nov 30, 2010
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    Yes.........
     
  10. Dodaman

    Thread Starter New Member

    Jun 15, 2016
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    Thank you sir. Very helpful. Later.
     
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