Forum Discussion

howardwheeler's avatar
howardwheeler
Explorer
May 16, 2018

Shut panels off first? Or controller to batteries?

I have forgotten the answer but do remember that there is an order of priority when shutting down your solar system. I have about a thousand watts of panels on the fifth wheel roof and a Morningstar MPPT controller. I need to shut down for a couple of days. Do I shut off the panels going to the controller first or shut off the power going out of the controller going to the batteries first? I know you guys know because someone out there told me a year ago! Sorry for my fading memory. I’m going to put a tag on my controller with the right answer. I’ve got breakers between everything for shut offs. Thanks
  • howardwheeler's avatar
    howardwheeler
    Explorer
    May 18, 2018
    Thanks. Panels off first, then controller. I’ve put permanent notes on my controller setup, so I won’t have to ask again.
  • RJsfishin's avatar
    RJsfishin
    Explorer
    May 17, 2018
    Yeah, like all those blown controller post here should be a good reminder
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    May 16, 2018
    Morningstar says to disconnect the panels first and connect them after the controller is turned on.

    I have a sign by the solar switches and the battery disconnect switches.
  • 2oldman's avatar
    2oldman
    Explorer II
    May 16, 2018
    DrewE wrote:
    It's never unsafe to do the panels first, since the controller has to deal with nighttime where there's (essentially) no power from the panels but the battery is still connected.
    Good answer.
  • BFL13's avatar
    BFL13
    Explorer II
    May 16, 2018
    Disconnect panels first and connect them last. Try not to have the panels connected when the controller is not connected to the battery, especially if you have any loads on the controller's load terminals (not normal for RV installation, but some folks do)
  • DrewE's avatar
    DrewE
    Explorer II
    May 16, 2018
    Generally panels to controller first; some controllers will die if they have input but nowhere to put the output power. Others may not care one way or the other.

    It's never unsafe to do the panels first, since the controller has to deal with nighttime where there's (essentially) no power from the panels but the battery is still connected. In other words, it's an expected situation that the controller needs to be able to deal with, whereas the opposite way around is not generally expected.

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