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Thread: Rand Solar Attic Fan/ Controller Question

  1. #1
    anoble1 Guest

    Default Rand Solar Attic Fan/ Controller Question


    Last year I bought a Rand 27 Watt Solar Attic Fan. Works Great! Only bad thing is that is does not run at night. Last week, I went to Costco, and they have a Solar Attic Fan Controller that allows the attic fan to run at night. The problem is that it is sold with Costco's attic fan (Please see link below)

    But, I have been wondering if the controller itself will work with mine, I called the maker and of course they said it would only work for theirs. It only have a positive and a negative, so does mine. I have gathered some specs to see if someone could tell me if it would work.

    Mine (Rand Attic Fan):
    Panel: 13 Volts/27Watt
    Motor: 18 Volts

    Costco 1010TR (Attic Fan):
    Panel: 17.2 Volts/10Watt
    Motor: 38 Volts

    Costco Controller:
    Power Output: 12 Volts/1.5 Amps

    That's all the info I have. Just trying to see if the Controller will work on "Mine" without burning the house down haha. I'm not an electrical genius.

    Any help will be appreciated.
    Last edited by anoble1; May 31st, 2011 at 9:06 PDT.

  2. #2

    Default Re: Rand Solar Attic Fan/ Controller Question

    Welcome to the forum.

    In order for a solar powered attic fan to operate at night it needs to be able to store energy in a battery to have it available when there's no sun. This would mean it would probably have a larger capacity solar cell, a battery, and some circuitry to regulate the charging of that battery - as opposed to a motor powered directly by the solar panel.

    Whether this would work to power another make's fan depends on its Voltage and current capacity. Your fan is 12 Volt, and the unit from Costco appears to be 38. Right there you have a problem: put 38 Volts to a 12 Volt motor and it will run very fast, and very briefly.

    Without more details about each unit (which the manufacturers seem loathe to give - they prefer marketing hype to facts) it would be impossible to say whether it could be adapted or not. Most likely not. If so, you'd end up doing some significant amount of modification which would amount to building your own battery and charge controller and possibly changing the solar panel as well.

    Perhaps someone else on the forum has a different idea/perspective.
    1220 Watts of PV, OB MX60, 232 Amp hrs, OB 3524, Honda eu2000.

    Ohm's Law: Amps = Volts / Ohms
    Power Formula: Watts = Volts * Amps

  3. #3
    Join Date
    Jun 2003
    pittsburgh, pa

    Default Re: Rand Solar Attic Fan/ Controller Question

    "The Solar Controller runs your Solar Powered Attic Fan after dark with the optional house electricity connection"

    that is what they said and it is like adding a wall wort or ac wall power adapter. this most likely can be used on yours if the current is sufficient to run your fan motor with. we don't know the current draw of your fan motor to say for sure, but any wall adapter you can find for 12v with 1.5a to 2a would be able to be placed to it instead of the costco one as long as connections match up. it will negate the pv so if you want to run solar you would need to unplug the wall adapter or put it on a switched outlet center.

    i looked for radio shack power supplies as this is a common adapter that can be used and did not see the type i had in mind that i know they used to sell, but this wall adapter may suffice if it has enough current to run your fan.
    also, be sure to place a blocking diode of the proper current rating (2a or 3a) inline with the pv output so as to prevent power from the wall adapter from dissipating power into the pv.

  4. #4
    anoble1 Guest

    Default Re: Rand Solar Attic Fan/ Controller Question

    So, it may work possibly. But I will need to get the Costco Controller, then get the adapter from Radio Shack and just switch the costco AC adapter with the radio shack?

  5. #5
    Join Date
    Jun 2003
    pittsburgh, pa

    Default Re: Rand Solar Attic Fan/ Controller Question

    no. the costco controller if i read them rght is not a controller, but really a wall wort type thing. or if you prefer different terminology it is an ac adapter or even a power supply. controllers are for pvs and if your setup already works with the pv then a controller is not needed. terminology is important to know what is what here so that one knows what one actually will need.

  6. #6
    bubba Guest

    Default Re: Rand Solar Attic Fan/ Controller Question

    Should not need fan at night, attic should cool on it's own. You don't want attic any cooler than outside temp., condensation becomes a problem. Best thing for an attic is continuous soffit vents, ridge vent and radiant barrier. No fans. Of course good insulation.

  7. #7
    Solar Attic Fans Guest

    Default Re: Rand Solar Attic Fan/ Controller Question

    Hi Everybody, I work for the manufacturer of the Solar Controller, U.S. Sunlight. Just to answer the question of the original poster, the Solar Controller is not recommended for use on any other brand of solar attic fan, there are too many possible voltage variables and the unit has only been thoroughly tested and approved for use on the U.S. Sunlight fans so far.

    Here is more info on the Solar Controller:

    Hope that helps, if there are any other questions I can answer, just let me know.


  8. #8
    Join Date
    Jun 2003
    pittsburgh, pa

    Default Re: Rand Solar Attic Fan/ Controller Question

    ok i see now that it is acting as a thermostat as well as being able to switch on the wall adapter. i guess if it has to do with warranty then you will be forced to use their stuff, but any dc source that falls withing the parameters the pv would provide will technically work in running the fan.

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