Forum Discussion

funpro's avatar
funpro
Explorer
Jun 15, 2015

solar panel blowout

I have an 80 watt solar panel installed on top of my 5th wheel. It was originally a portable solar panel that was put permanently on top. The controller was left attached to the underside of the panel. It was connected to two 6 volt marine batteries in the 5th wheel. I have a kill switch so there was no power going into the trailer. Trailer was unused for about 5 months. Went to check it out and found that the cord from the solar panel to the batteries was fried at the fuse and in two separate pieces. Batteries were dead. Any suggestions on why this happened.
  • christopherglen's avatar
    christopherglen
    Explorer
    Jun 15, 2015
    You *should have 3 fuses, one at each power source. The panel, the controller, and the batteries. Each fuse ~25% bigger then the expected max for charging, but not oversize for the wiring. The panel fuse should be at rated output + 25%, the other two fuses should be panel WATTAGE /10, +25%. As long as the fuses aren't to big for the wiring, that covers all charge controllers - mppt and shunt. Did I mention do not use fuses to large for the wires? Put the fuses as close as reasonable possible to the power sources.
  • funpro's avatar
    funpro
    Explorer
    Jun 15, 2015
    Thanks for the input. I am trying to attach a photo of the broken and burned fuse connection. The fuse is about 1 foot from the battery connection. The controller is up on the roof and about 5-6 feet from the batteries.
  • full_mosey's avatar
    full_mosey
    Explorer
    Jun 15, 2015
    funpro wrote:
    I have an 80 watt solar panel installed on top of my 5th wheel. It was originally a portable solar panel that was put permanently on top. The controller was left attached to the underside of the panel. It was connected to two 6 volt marine batteries in the 5th wheel. I have a kill switch so there was no power going into the trailer. Trailer was unused for about 5 months. Went to check it out and found that the cord from the solar panel to the batteries was fried at the fuse and in two separate pieces. Batteries were dead. Any suggestions on why this happened.


    I believe you meant to say that the "cord between the controller and the batteries" was fried. This would have been caused by a short on the battery side wiring because it is unlikely that an 80W panel could fry the wiring.

    When you rewire, place the controller as close as possible to the batteries.

    HTH;
    John
  • Vulcan_Rider's avatar
    Vulcan_Rider
    Explorer
    Jun 15, 2015
    funpro wrote:
    found that the cord from the solar panel to the batteries was fried at the fuse and in two separate pieces.


    Something shorted out.
    Wires.
    Batteries.
    A component in the controller...which drained the batteries.

    BUT it would appear that the fuse was installed wrong or the wiring shorted out between the fuse and the batteries or the fuse was just simply too big. Did the fuse blow ??

    Hard to say for sure without seeing a connection diagram and seeing the wiring.

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