Power source switching options (for AC pump)

Lot2Learn
Lot2Learn Registered Users Posts: 2 ✭
in Solar Water Pumping #1
Hello,
I am requesting recommendations on the following:

I want to keep an existing AC pump in place and power it with PV (and inverter). For periods of poor or no insolation, I want to use the grid as the power source. No holding tanks, no battery banks - other than enough to power the parasitic load/inverter. And, just for this one application, no DC pumps.

So, when wanting the grid as backup, will an AC-to-DC Converter and a manual switch cheaply, yet professionally satisfy the power source switching? Or, is the more expensive automated solution (like the Outback Sealed FX2348ET Inverter) the "only way to go"? I do understand the cost of the solution and the customer's desired lifestyle (i.e. willing to go flip a switch?) are two large factors.

Thanks in advance for any time spent on this question.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Power source switching options (for AC pump)

    Just to make sure the specs are clear:

    The pump is AC.
    Most of the time it is to be powered from PV recharged battery with an inverter to supply the AC.
    When this is not feasible there is grid to power the pump.
    Most desirable for the power switching to be 'seamless' i.e. no human monitoring or changes if possible.

    I believe there is an alternate choice of using PV driven grid-tie to offset the AC used by the pump?
    If so, is selling to grid allowed? If it is not then that becomes more complicated.

    Everyone will want to know the specs on the pump motor too.
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #3
    Re: Power source switching options (for AC pump)

    I have seen pre-made boxes, as per attached, where you run a off the shelf pool pump using solar power.

    In SA, they where selling for:
    Pump Inverter – R9 815 ex VAT (includes SABS standard (Orange) control boxes with Fuse, Terminals, ON/OFF switch, automatic conversion from Main grid to Solar panels power)
    For a 1,1kw pool pump, would have needed 4 x 300wp

    Attachment not found.

    AND

    Attachment not found.
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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  • Lot2Learn
    Lot2Learn Registered Users Posts: 2 ✭
    #4
    Re: Power source switching options (for AC pump)
    South Africa wrote: »
    I have seen pre-made boxes, as per attached, where you run a off the shelf pool pump using solar power.

    In SA, they where selling for:
    Pump Inverter – R9 815 ex VAT (includes SABS standard (Orange) control boxes with Fuse, Terminals, ON/OFF switch, automatic conversion from Main grid to Solar panels power) For a 1,1kw pool pump, would have needed 4 x 300wp

    Apologies for the delayed response. Thank you! Do you happen to have a link for that company/product?


    Cariboocoot wrote: »
    Just to make sure the specs are clear:

    The pump is AC.
    Most of the time it is to be powered from PV recharged battery with an inverter to supply the AC.
    When this is not feasible there is grid to power the pump.
    Most desirable for the power switching to be 'seamless' i.e. no human monitoring or changes if possible.

    You brought my attention to the fact that I had contradicting thoughts on my initial message. Sorry for any confusion. To clarify, I'd like to consider power switching methods for backup of two different scenarios: (1). where the AC pump is left in place and normal operation means it is powered by PV (2). where I decide to install a DC pump (in this case NOT an SQ-Flex) and normal operation is to power it with PV. So, my questions for the two scenarios are: when AC grid backup is needed.....

    1). What are my power source switching options to keep the AC pump running? (i.e. spend the money to have an Outback inverter + add "xyz" piece of equipment)
    2). " " keep a DC pump running (i.e. buy an AC-to-DC converter...etc)

    Instead of just the "Most desirable...seamless" option, I want to know the various ways to do the power switching, particularly if there is an inexpensive solution (versus the higher cost Outback inverter).
    wrote:
    I believe there is an alternate choice of using PV driven grid-tie to offset the AC used by the pump?
    If so, is selling to grid allowed? If it is not then that becomes more complicated.

    Everyone will want to know the specs on the pump motor too.

    That is an option (AC pump powered by grid and just sizing a small grid-tie system to offset what the AC pump is costing the homeowner). Yes, selling back to the grid is allowed. I don't want this to confuse anyone, though. This is a third option so perhaps we leave that out? Your call. Selfishly, I benefit from you and others are willing to discuss.

    The pump is a 1HP Pedrollo (PKm 80 model) Single-phase 220V, 50Hz drawing 5.2A
    http://www.pedrollo.co.uk/pdf/Product%20Pages/Peripheral/PK/PK.pdf
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  • South Africa
    South Africa Solar Expert Posts: 295 ✭✭✭
    #5
    Re: Power source switching options (for AC pump)

    Indeed I do. They are: http://www.gwstore.co.za/ They are quite a nice bunch.
    Email: Jason Sole jason@gwcholdings.com
    Email him the pics and or pdf.

    Attachment not found.

    Dollar exchange rate is in your favour, just make sure about 220v @ 50hz for SA.

    Personally I believe that a box like this is cheaper long term than a DC solar pump due to costs of replacing pumps every number of years. At least, that holds true for us.
    5kVA Victron Multiplus II, 5.2kW array, 14kWh DIYLifepo4 bank, all grid-tied.


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