Whelp. A week later and the batteries dropped down to 9v again, with the High AC or AC Overload faults. Bummer. So there's something else going on. I've been at this RV park many times over the past 5 years without issue, but maybe my current spot has bad power, or maybe the Magnum's going bad. (I've emailed Magnum to ask if what I'm seeing would be expected if the Magnum was failing.)
I've got the Progressive Industries EMSLCHW50 or the Camco Defender queued up in my Amazon cart. Will wait to hear from Magnum before ordering.
I've also set my charge rate to 50%. It used to be 10%. In what I've read, for 6v batteries, it should be about 10% of the amp hour capacity. My capacity's 460 amp hours (230AH each battery, 2 series strings in parallel, total 460, unless I'm mistaken). My Magnum MS2000 max charging rate capacity is 100A. So setting it to 50% gets me 50amp, which is close to the 10%. I think that's right, at least.
