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      I noticed that when I switch off the battery cut-off switch that there remains a faint glow from the panel light for any panel switch inadvertently left in the ‘on’ position.

      I am concerned that the cut-off switch is faulty and so have made a point of disconnecting the domestic batteries, in addition to switching off and removing the cut-off switch key when leaving the boat.

      I would appreciate it if anyone could let me know whether there is an explanation for glowing lights or if I should just replace the cut-off switch.

      Bernard Power

      Adagio, B32



        Firstly, I very much doubt that the battery switch is faulty.

        The main battery switch (MBS) is in the negative battery line so any circuit, and the corresponding LED, will have 12V positive applied when their switch is turned on, even when the MBS is off. The circuit should not be energised, though, if the MBS is off because there is no connection to battery negative. However, if there is any (other) connection direct to battery negative that bypasses the MBS, a return path for the LED can be established through the equipment to which the direct line is connected, even when the MBS is off.

        Do you have any electrical items that are wired direct to battery negative, bypassing the MBS? The most likely is the domestic radio; these are sometimes wired direct to the battery so that pre-set station info etc isn’t lost when the main power is removed.

        Another possibility is a permanently wired battery charger.

        You can check for such connections by looking for any wires coming from the battery negative terminals, other than the thick main feeds.

        If you have any additional wires, disconnect each in turn and see if the glowing LED goes out.

        Good hunting!



          Many thanks Roger,

          I had ‘ground’ the Raymarine S1 SmartPilot Computer directly to the battery negative. Maybe that’s the problem.

          I will check it out and re-route to grounding wire to the engine block if necessary.

          I’m not sure if anything else is connected directly to the Battery Negative. I’ll check this out also.

          I’ll let you know how I get on. (Adagio is laid up for the winter 100 miles from home so it may be a few weeks before I get to do the checks).




            Hi Bernard
            I am a little confused with Rogers reply, he mentions that the main battery isolator is in the negative battery supply. I have a B30 2006 and both the engine & house battery isolators are in the positive supplies. The negative is connected between both batteries and runs to a common rail behind the switch panel. Not sure whether I am helping with your problem 😕 .

            Best of luck


              It sounds as though Bavaria have changed their approach to battery switching then. On earlier boats (AFAIK) there is only one battery switch and this switches the negative (‘earth’) connection to both batteries.


                The rule always was to supply a black key if the isolator is fitted in the earth lead and a red key if fitted in the live side. Of course Bavaria may not have followed this practice.


                  They haven’t with Playtime. My battery switch, in the negative line, is a detachable (when switched off) metal handle, with no colour or other marking.

                  After owning 3 previous boats, all with battery switches in the positive (non ‘earth’) side, I was surprised when I discovered that Playtime switched the negative line. However, on thinking about it, I could not actually see any problem with the arrangement and it means there is only 1 switch for both batteries, rather than 2 or a 1 – 2 – Both switch.



                    The main battery switch is on the negative side on Adagio, a 2002 B32. Thus Roger is correct in his assessment.

                    My problem is that there appears to be a negative ‘leak’ when the MBS is off.
                    This appears as a faint glow (rather than the normal bright glow) on the switch panel for any panel switches in the ‘on’ position after the MBS is switched off (and key removed). Switching off the panel switch makes the glow disappear.

                    This why I thought that the MBS might be faulty.

                    Negative connections are provided via the negative bus bar. Thus should be isolated when the MBS is ‘off’.

                    As Roger suggested, I need to check all my negative connections.


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