Forum Discussion

stevenal's avatar
stevenal
Nomad II
May 27, 2018

New camper with solar and battery disconnect

My new 'foot has a remote battery disconnect. The control is handily reached from the door, and it disconnects the battery from the converter, alternator, and loads. The solar controller, though, is wired directly to the battery. Is there a reason for the partial disconnection?

Do forum members use remote disconnects? I'm not sure the feature is worth the added voltage drop. Never missed having one on the old camper. The PD converter should keep the battery healthy even when stored.

Finally, the instructions for the solar controller call for fusing the negative lead next to an illustration showing it in the positive lead. I think Bigfoot put a circuit breaker in the negative lead. This seems wrong with a negative ground chassis system. Comments?

Thanks.
Truck Campers
  • stevenal's avatar
    stevenal
    Nomad II
    May 29, 2018
    I spoke to support at Switch Energy yesterday. Not a holiday in BC. He states it doesn't matter whether fuse is in the positive or negative, since interrupting the loop from the battery source during controller failure is what's needed. I'll move the controller positive lead from the battery to the other side of the circuit breaker, and all should be well. The breaker is on the battery side of the disconnect. Thanks for all the help.
  • HMS_Beagle's avatar
    HMS_Beagle
    Explorer
    May 28, 2018
    A properly working solar charge controller should be fine connected to the batteries always, except as was noted above when you are working on them (12V will not shock anyone, but might make some sparks). For fusing, solar panels are an inherently current limited device, and the wiring should be sized to handle all of the current they can produce short circuited. However at the battery end, there should be a fuse or breaker, since the batteries can effectively source current without limit. If you get a fault in the wires between the battery and first fuse/breaker, it could start a fire.
  • work2much's avatar
    work2much
    Explorer
    May 28, 2018
    I like using circuit breakers instead of fuses as they can be used as a switch. You could replace the factory fuse between the solar charge controller and the Battery with a circuit breaker and shut down solar power to the bank this way. In addition I believe it wise to install a battery switch at the battery. This is much easier and safer way to kill battery power completely without having to put a wrench to the battery terminal.

  • Buzzcut1's avatar
    Buzzcut1
    Nomad II
    May 27, 2018
    I have a disconnect between the panels and the controller along with an inline fuse. The reason is so that I can isolate the batteries and the solar panels from the system so I don't get shocked when working on electrical components.
  • stevenal's avatar
    stevenal
    Nomad II
    May 27, 2018
    Avoiding accidental discharge evidently avoids charging from the converter as well. And since it's stored indoors, there's not much solar charging going on.

    I'll keep that smoke in mind.

    I was mistaken above. No fuses or breakers were installed at all between solar control and battery.
  • pianotuna's avatar
    pianotuna
    Nomad III
    May 27, 2018
    Solar doesn't need a disconnect and if it does have one, it should be between the panels and the controller. Some controllers may let the magic blue smoke out if they are not first connected to a battery bank.

    There does need to be a fuse near or on the battery for the cables going to the charge controller.
  • Kayteg1's avatar
    Kayteg1
    Explorer II
    May 27, 2018
    The idea is that you can disconnect the battery from camper to avoid any potential discharge, while still having solar panel topping it up.
    That said, last winter my Lance killed the battery this way. I still did not figure out what happen as the recharged battery stays good for several days, but seem sometime in winter either the panel, or the controller shorted.

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