Hi Baker, Could you please post a picture of your labeled Yamaha isolator aux system?
I've been reading all these posts very carefully, (Perko/Guest/BEP discussions) but have kept out of the conversation because I don't understand it; I don't understand it as it relates to our Parker.
What you mentioned does make sense to me.... With our Guest switch on either #1 or #2, with the engine running, the other battery (both batteries) are still receiving charge; 14.1 to 14.5 Volts. (Measured with Fluke Volt/Ohm multi-meter)... With the engine off, and using DC power to run electronics for multiple hours at anchor, (4, 6 or 12+ hours, even overnight) or just drifting for half a day, the battery I selected will occasionally weaken to near 12.0-12.2 V (again, tested with Fluke multi-meter)..... But the 'saved/reserved' battery will still be strong (around 12.7 V static), meaning, the strong battery is not being weakened/drained by the weak/drained battery through the Guest switch. What I'm experiencing, is all I would expect from any battery-switch-system...
Is what I describe here; what we experience on our boat, not the norm? If not, why do the Perko Guest battery switches even have a #1 and #2 setting? If not to create the situation I have, there would be no use to have a #1 and #2 setting. It seems from what I've been reading, that other people with Perko or Guest battery switches are not experiencing what I do, and from your post, what you are experiencing....