Accidental Enlightenment
Kintala's batteries are not playing well together. They should, both AGM, both new, both installed at the same time, both fully charged to start. But left together overnight and, come morning, their voltage readings are down around 12, sometimes a little less. It turns out, if we send them to (electrically) separate rooms for the night, come morning the AUX is at 12.8 while the MAIN, which has carried the boat load the whole night by itself, is still showing 12.25 or a little more. Not a fix, but a way to keep going for now. The only thing is remembering to bring both batteries back online before waking up the Wester-Beast and starting the day's run.
Today I got out of my morning routine and forgot to switch the batteries.
A couple of hours later the Wester-Beast, after days of running smoothly, started the RPM surge thing again. (Remember, they have been really short days. That will be important in a minute.) We tried opening up the filler cap again but it made no difference. We looked around the engine compartment, nothing leaking. It truly sounded like the engine was actually taking on a load, like it was trying to push the boat up hill or something. But that can't be, right? Boats on the ICW don't have any hills to climb, the RPM surge was surely a fuel problem of some sort. But for some reason the Beast's complaints reminded me that the batteries were configured wrong. We flipped off the DC master, put both batteries on line, and brought everything back up.
The Beast instantly settled into a easy lope that lasted the rest of the day. Excuse me?
The suspicion now is that the high tech voltage regulator that controls the high output alternator driven by the Wester-Beast to charge the batteries gets glitched when the batteries (or battery as it were today) hits a full charge and is supposed to go into a “float” mode. That takes several hours, the same amount of time it takes for the RPM surge to show. Give the regulator an electrical smack by changing the battery load and all is well (like slapping the side of the old TV cleared up the picture).
I haven't reached full enlightenment yet; but the accident of leaving the batteries mis-configured this morning seems to have shed some light. A glitched alternator regulator probably doesn't explain why the batteries are bickering, but we are onto something here … at least I think we are.
Tonight we are anchored within sight of NASA's vehicle assembly building. It isn't much of an anchorage but should be okay for tonight. And being this close to Cape Canaveral is just cool.