Wiring an SQFlex pump along with a charge controller to both charge batteries and pump.

cruiser guy
cruiser guy Solar Expert Posts: 87 ✭✭✭✭
in Solar Water Pumping #1
Has anyone tried such a setup? There is something similar to this shown on page 17 of the Grundfos Product Guide for the SQFlex system. The problem is it's a little short on specifics.

What the ideal system would look like for me is one where the SQFlex only uses solar power to pump water but when the pump does not need to run the solar power can be used to charge a battery bank which is then used for other purposes.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: Wiring an SQFlex pump along with a charge controller to both charge batteries and pu

    Could you hook up an "in float" signal (from Outback or possibly other MPPT charge controller) to the float input on the pump controller to "allow" the pump to run when the battery is fully charged and water is needed?]

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • cruiser guy
    cruiser guy Solar Expert Posts: 87 ✭✭✭✭
    #3
    Re: Wiring an SQFlex pump along with a charge controller to both charge batteries and pu

    This is the reply I received from the Grundfos rep.

    "Yes, you can connect a charge controller and battery system for the SQFlex. The one that we offer is a Morningstar PS15M-48V but you could use any commercially available controller."

    No wiring diagram with the reply but I am wondering if they are running the pump off the "Load" terminals? Is that possible? I'd have thought it is too high of a load for the "Load" terminals.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    Re: Wiring an SQFlex pump along with a charge controller to both charge batteries and pu

    You could set up a Xantrex, MorningStar or other controller as a "dump controller".

    Program your solar controller to charge to 59 volts. And the Dump controller to 56 volts charge and 52 volts float (if programmable). That way, the pump would run when the battery bank is "full"...

    I probably would still prefer an Outback or similar charge controller with an "in float" output you could use to turn on the pump.

    Solar charge controller and a dump controller running at the same time (where the dump controller is "primary") seems like you are running a balancing act trying to keep the batteries full and running when in float.

    Dump controllers are not the best at keeping batteries fully charged (either full ON or full OFF--plus possibly lots of pump cycling which is probably not great either).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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