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melloftus's avatar
melloftus
Explorer
May 12, 2019

Battery Disconnect switch/charging - ON OR OFF?

We recently purchased a (New to us) 2008 M-21CKS Mallard by Fleetwood being first time Trailer owners we have hit a few bumps in the road but so far so good. We enjoyed our first outing recently where I selected a full RV hook up site where we could really put her to the test and make sure everything worked... which thankfully it did! But we have a trip coming up where we will be dry camping and I really cant find any information on the Battery disconnect switch and how that works with charging our batteries. The last thing i want is to damage our power converter as we have already has a costly repair due to a leaking skylight-rookie buyers rookie mistake.. super lucky lady with a very handy hubby here :@)
The Battery Disconnect switch is orange and located outside near the battery bank and from what I can tell it just has a on/off function
1) If connected to shore power ( Camping or at home) should the switch be turned to "ON" ? The first time we took her out I left it off now I am wondering if that was a mistake..
I would assume this would also be the same if connected to generators.
2) I would like to charge up my batteries before heading out on our 5 day boondocking adventure.. will the batteries charge if the switch is in the off setting?
3) just checked with the hubby and our truck has a 7 prong connection..if the answer to my above questions is yes it should be set to "on" as I understand we can charge those batteries of the truck alternator as we are heading to our destination.

17 Replies

  • always leave the switch on unless in storage to prevent drainage.
  • CA Traveler wrote:
    pianotuna wrote:
    To fully charge before a trip turn it on seven days before you leave. :(
    Anything over 1 day and I'd be looking for a new charger. :B

    Yep, one of my first mods was pulling out the WFCO charger and put in a good charger that I can force into bulk charge mode.
  • pianotuna wrote:
    To fully charge before a trip turn it on seven days before you leave. :(
    Anything over 1 day and I'd be looking for a new charger. :B
  • The long wire run from the alternator to the RV batteries causes significant voltage drop which results in limited charging while driving. So charge before driving with shore or generator.

    You can add larger wire and connectors from the alternator to the RV and/or install a DC-DC converter device which will increase the voltage and amps to the RV batteries for a better driving charge.
  • Congratulations on the trailer and welcome to the forum. As Pianotuna said you basically need to have the switch on for all questions.

    1. The switch must be on for the battery to charge from shore power
    2. See answer above.
    3. Yes you can charge via the truck alternator if the switch is on. But really the alternator doesn't give a good charge. I would recommend your scenario 2 above. Plug the trailer in at home and let the battery charge for a few days or more.
  • When ever you are using the RV set the switch to on.

    To fully charge before a trip turn it on seven days before you leave.

    The seven pin connector does only a tiny bit of charging while driving.

    Have a wonderful trip!

    Welcome to the forums.