Need Insight for Solar Greenhouse Panel for van and pump applications

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tokso
tokso Registered Users Posts: 7 ✭
in Solar Beginners Corner #1
Newbie here. I am interested in pursuing using PV to power some fans (approximately 4 or 5 at 2.6 amps/12V) plus 1 or 2 higher amperage 12V bilge or recirculating water pumps for hydroponics.

I wish to spend the least amount of money but I would rather not do anything then spend the bucks on something that will not work (or is too expensive in payback).

The main detail is that because it is for plants, the fans and pumps only need to operate during daylight hours. The fans will have a 12V on/off temperature controller (on at 70+ degrees, for example) and the pumps only run at intervals during the day to flood the hydroponics.

I was interested in the Kyocera Solar KD135SX-UPU - 12 Volt, 135 Watt Solar Panel With Junction Box, pole-mounted sideways with an Iron Ridge UNI-SP/01A.

Am I too newbie to think that this panel, along with essentially wiring the fans and pump/pump controller in one big 12V circuit will suit my needs?

And if not, would it be possible (or better) to run an inverter off the panel to provide 120V ac and then use that to power 120v AC fans and 120v water recirculation pumps? And if so, what products (PV/inverter) do you recommend? Also keep in mind that this is a wet-condition install (either to the weather or inside a humid greenhouse), so any inverter would either need to be weather-resistant or be inside a weather-resistant box.

Again, this only needs to run during daylight hours (fans when it gets too hot) and the plants themselves will only actively grow/uptake nutrients during day-light.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Need Insight for Solar Greenhouse Panel for van and pump applications

    Welcome to the forum.

    You may not believe it, but this comes up a lot. Sometimes it's attic fans, other times it's livestock fans, but solar powered fans are a hot topic around here. (Sorry; couldn't resist).

    It's a question of getting the fan needs balanced with the power needs. You might find this thread of use: http://forum.solar-electric.com/showthread.php?t=11597&highlight=solar+fans
    I believe there's some links to direct-from-solar fans in there.

    The pumps may not like the varying output of solar panels as much. This is an instance where it may be necessary to use a small battery and charge controller to maintain a steady power supply for them. In that instance you may want to include the fans as part of the same system or have two separate systems.

    You'll have to do some math in either case. How much the pumps/fans draw * the hours they'll be on to get an idea of how many Amp hours need to be supplied. That could be tricky with thermostatically controlled fans.

    You might want a nice little timer like this: http://www.solar-electric.com/fldctico.html Good for turning pumps on and off.

    One other bit of advice: don't build the greenhouse at 52 lat like I did: 50C in Summer with all vents open! Mine needs some serious rethinking. :blush:
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  • tokso
    tokso Registered Users Posts: 7 ✭
    #3
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    Re: Need Insight for Solar Greenhouse Panel for van and pump applications
    Cariboocoot wrote: »
    Welcome to the forum.

    One other bit of advice: don't build the greenhouse at 52 lat like I did: 50C in Summer with all vents open! Mine needs some serious rethinking. :blush:

    Thanks for the input.

    This greenhouse is in the Pacific NW USA and on day's like today ( ~95F) are running well over 120F with four roof vents, rear louver vents and an open front door and a 50% white shade cloth over the roof.

    I am looking at the "Endless Breeze" 12v fans which seem to have good reputation, although who knows what a greenhouse will do to them. They are rated at 2.58 amp/hour.

    Two other questions:

    1) The Kyocera would ideally be putting out 7.63 Amps max. Do 12v appliances care about how much amperage they are getting?

    2) Would it be possible to split the system into a 12v direct PV loop for the fans and a 120v output (inverter/battery) for the hydroponics?

    My main concern with a battery system is that on a hot night the fans might keep running and discharge the battery.
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  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    #4
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    Re: Need Insight for Solar Greenhouse Panel for van and pump applications
    tokso wrote: »
    Thanks for the input.

    This greenhouse is in the Pacific NW USA and on day's like today ( ~95F) are running well over 120F with four roof vents, rear louver vents and an open front door and a 50% white shade cloth over the roof.

    I am looking at the "Endless Breeze" 12v fans which seem to have good reputation, although who knows what a greenhouse will do to them. They are rated at 2.58 amp/hour.

    Two other questions:

    1) The Kyocera would ideally be putting out 7.63 Amps max. Do 12v appliances care about how much amperage they are getting?

    2) Would it be possible to split the system into a 12v direct PV loop for the fans and a 120v output (inverter/battery) for the hydroponics?

    My main concern with a battery system is that on a hot night the fans might keep running and discharge the battery.

    First off appliances only draw as much current as they need. If they don't add up to as much current as your panel can produce, the output voltage from the panel will increase slightly. Anything designed to work off a car battery will be able to handle a variable voltage that goes from about 10V up to about 18V or more so this isn't really a problem.

    Of course just because a panel is rated at producing 7.63 Amps doesn't mean that you'll actually get that much from it. That is what it produces in ideal circumstances and real life is seldom ideal. You're best off assuming you'll only get 60-75% of that.

    Look into 12V bilge pumps for water pumping. I like the Tsunami brand because they come with a 2 year warranty. They are cheap too.
    This one will move up to 500 gallons per hour and only costs $18
    http://www.amazon.com/Attwood-Corporation-Bilge-800Gph-Tsunami/dp/B001O0D6II/ref=sr_1_1?ie=UTF8&qid=1311629587&sr=8-1
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Need Insight for Solar Greenhouse Panel for van and pump applications

    so what will the requirements of all of your pumps and fans be when it's raining and there's little solar power being produced? will you just abandon running those items based on if there's sufficient sun? these are some things you need to ponder. if you can do without when there's insufficient sun then you could probably add a relay to inhibit 12v loads if you use a battery. if not then straight running and drop off when no sun is present.

    i know it sounds oversimplified, but you can carry on with your own thoughts as well as ours from this simplification. it will evolve in thought and on paper first until you are sure of what you get is what you need.
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