Circ Pump for small pool

PR_Gary
PR_Gary Registered Users Posts: 3
in Solar Water Pumping #1
Hi All, I've been scouring the web looking for a pump to suit my needs with very limited luck. I'm building a very small (3,500 gal.) above ground concrete plunge pool. I'm living in Puerto Rico and so have the twin solar motivations of strong abundant year round sun and sky high electric rates. The pool has its mechanical room underneath it, so the pump will have a flooded suction and return and will essentially be a recirculator with very little head. I'm looking for a pump that I can use PV direct, no batts, and my calculation tell me that I'll need about 15-20gpm (about 1000gph) in order to get 2 turnovers in 6 hours of a sunny day and at least 1 on a not so sunny day. I will confess to being naive about this whole DC direct to PV idea, I'm assuming some sort of controller will be needed (LCB?) and that maybe only certain types of DC motors are suitable. All the pumps that I've seen for this sort of application are waaay too big for the volume I have. I really don't wanna pay for that kind of overkill. So, if anyone has suggestions, they are most welcome. Also can any DC pump be used for solar? I've found a few pumps in the correct range, but not on "solar product" sites. Are there pitfalls I should be aware of? Does one oversize the PV to provide for extra early day/late day/cloudy day power? Thanks for any/all suggestions, Gary
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Comments

  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #2
    Re: Circ Pump for small pool

    Could you run it from AC?
    If so look at INTEX, they make those simply above ground pools and pumps.
    You could get their 1500gph model which will suit your needs for around $80 and they don't use all that much power.
    They also have a smaller one, maybe like 500gph which is even cheaper and uses less power.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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  • PR_Gary
    PR_Gary Registered Users Posts: 3
    #3
    Re: Circ Pump for small pool

    My desire for off grid is multi-fold. Electric is pricey here (.30/kwh), and unreliable (interruptions, including fast chatter, spikes, low voltage). Electronic devices get toasted fairly commonly. Also in the event of long term outage ( think tropical storm/hurricane) I wanted to be able to use the off grid pumping to feed a toilet and shower in a nearby bathroom using pool water. In fact I think of the pool as more like a cistern that I can soak in. That being said, I have checked out those Intex systems and they are rather attractive for my small needs. Even if I go for off grid pumping, I might use one of their SWGs on an AC line. (again, I would fear the delicate electronics though)

    I suppose a small inverter system would be a possibility also.
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  • raysubtropical
    raysubtropical Registered Users Posts: 14 ✭✭
    #4
    Re: Circ Pump for small pool

    Not sure if you have solved the pump problem yet or not....I used a 90 vdc motor with a coupler to a vane pump with an inline fuse .....it always started in the morning and ran all day thru a sand fitter....and the small pool was always clean ....
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: Circ Pump for small pool

    Welcome to the forum Ray!

    What DC pump did you use? Brushed motors may last 6-12 months when operating as a pool/circulation pump before the brushes need replacing.

    Electronically commutated motors/controllers are very nice, but not cheap. :cry:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • PR_Gary
    PR_Gary Registered Users Posts: 3
    #6
    Re: Circ Pump for small pool

    My problem is that I don't know enough about dc motors. From what I gather a Linear Current booster can be used to increase current (at the expense of voltage) to allow a pump to run earlier in the morning and later in the afternoon, but what do you use to prevent the pump from trying to run at a voltage so low that it can't turn? Are there LCBs out there with low voltage cutoffs? Is one type of pump better at this application than others? Lorentz has a pump/controller just for this purpose , but way big for my needs and very pricey.
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