Well Pump and Charge Controller on Same Array at Same Time

I have a Dankoff Well pump powered by 48 volt solar. And also have a OutBack MX60 charge controller connected to a 12 volt battery bank. These are powered off of the same 48 volt 300 watt solar array. I try to have it so either the array is powering the solar well pump or charging the batteries through the MX60, but not both at the same time.

Is it OK to have both the charge controller and the well pump pulling off of the same array at the same time? As long as the pump runs and the batteries get charged can I damage anything by doing this?

Thanks

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,482 admin
    Re: Well Pump and Charge Controller on Same Array at Same Time

    At the very least, you will probably confuse the heck out of the MPPT algorithms.

    I don't think it would be a good idea to share the panels between the MPPT Charge controller and the pump.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Well Pump and Charge Controller on Same Array at Same Time

    This is basically the same question as came up in this thread: http://forum.solar-electric.com/showthread.php?t=7641

    From the pump's point of view you're better off with the MPPT controller as it will "power down" when the pump tries to draw from the panels; the diversion of current to the pump 'looking like' low panel output to the controller. A PWM type wouldn't be as forgiving, as it will simply try to draw everything it can unless the batteries are fully charged.

    In either case the main concern is possibly not enough power available when the pump tries to start. Even with MPPT this could cause a few 'false starts' which would be rough on the pump and may eventually shorten its life. But most direct-from-solar water pumps are designed with this in mind, expecting the power available to range from 0 to full, so this shouldn't be a problem if the system is designed properly. (I almost wrote "well designed"! :p )

    The more panel, the less problem. If yours is working I wouldn't worry about it.
  • System2System2 Posts: 6,290 admin
    Re: Well Pump and Charge Controller on Same Array at Same Time

    May be one of those situations where you simply apply the logic "if it's not broken, do not try to fix it".
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