Question on solar for an electric gate

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  • Cruft_throne
    Junior Member
    • Nov 2020
    • 2

    Question on solar for an electric gate

    I have a LiftMaster LA400UL opening and closing my driveway gate.

    This is a swinging gate actuator with a 24VDC motor. It currently runs off an extension cord connected to the house, but this cord is long overdue to be replaced and because of a number of obstacles, burying a line to it is going to be cost prohibitive.

    It looks like early models of this system could be converted to solar using a kit provided by LiftMaster
    Unfortunately I have a new model and according to their documentation page, solar is not supported. I reached out to them to try to get an answer as to why (wondering if this was just a policy change or if there is something physically different in later models) but never received a response. So rather than use their kit I think I'll just try to rig something up myself which will hopefully be cheaper anyway.

    The enclosure I have includes two small 12V 7AH batteries. See below for a photo of the wiring diagram that was included with my current install.
    There are some specs for the official solar kit included in that diagram as well: (2) 10w 12v panels.

    Hoping to get some input from the community here. What does it look like I will need to make this work?
    I'm thinking (2) 10-30w 12v panels and a charge controller wired directly to the batteries. I'm confused about the wiring though--the diagram states the panels are wired in parallel, but considering the 24V motor shouldn't they be in series?

    la400ul.jpg

    Thanks

  • bcroe
    Solar Fanatic
    • Jan 2012
    • 5199

    #2
    The drawing looks like series panels, 24VDC everywhere. Do the batteries act as backup
    to allow the system to function when plug in power is gone? If so, just coming up with an
    adequate 24VDC solar system connected to the battery input should work. But tiny panels
    may not be up to the job, depending on clouds, season, and how often the gate operates.

    Check the output numbers on that line transformer, looks to me like it is too small and the
    assumed supply wiring too light to supply gate power by themselves. Bruce Roe
    Last edited by bcroe; 12-13-2020, 11:00 PM.

    Comment

    • bcroe
      Solar Fanatic
      • Jan 2012
      • 5199

      #3
      Do not too quickly assume that a new buried line is not the best solution. I just
      finished burying 300 pounds of aluminum wire here. Bruce Roe

      Comment

      • oregon_phil
        Solar Fanatic
        • Jan 2019
        • 497

        #4
        I have a similar gate set up with a 12VDC battery and power brick. It also has the option for solar charging. The battery is the main power plant for the gate opener. The gate opener will not function on the power brick or solar alone. I can run the gate opener off of the battery alone for months. The power brick and/or solar panel is low power device that connects to a battery maintainer/charger which then connects to the battery.

        If you look at your manual page 42 to 45 (rather than the schematic), there are a lot of options for different solar panel configurations. They give different options for power rating, quantity and how you should hook them up.

        I think bcroe is right, the solar panels go to circuit board connector and right back out to the batteries.

        OK, I'm a mechanical guy, not an electrical guy. There is a diode in the wiring harness to the solar panels that I think prevents current flow from the battery into the solar panel. Without the diode, the solar panel heats up and consumes power from the battery.

        Comment

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