I think my course of action is set because of our locale, but wanted to run it by the group for some expert advice. This morning we awoke to the unmistakable scent of battery acid in the passageway. We have been dockside for 4 days with good shore power and the charger showing 'float' but this morning one of the batteries boiled off, taking its paired partner with it. Both batteries were very, very hot. Shutting down the charger and throwing the disconnects we did what any good Amel owners would do in a crisis and went to breakfast and then went battery shopping. Not much to be had here, and what there is runs a pretty penny.
I'm inclined to just run with 6 of the 8 batteries until I can find replacements that are better fit.
The other option is to add two Lead Acid Gel-cells to the mix of lead acid flooded batteries. I presume that they are essentially compatible, unlike trying to mix AGMs and lead-acid (which we will not consider).
Interesting note is that we add a small amount of distilled water every month to the battery bank, and the day after I added water we had this failure. Luckily, we noticed and caught it in time to prevent a battery from popping (which we have seen and heard on our RV).
Would it be OK, at least in the short term, to add a couple of lead-acid gel cell batteries (sealed, maintenance free) to the other six flooded batteries, or is there a known charge rate/compatibility problem that might mess up the whole charging system. Running on six batteries is probably OK, except I'll have to secure them to prevent movement and it'll mean more frequent generator runs.
The dying batteries are currently sitting on the dock, still quite hot and discharging internally. What a way to go....
