Sorry I've been traveling and missed the start of this thread. I've been researching shore chargers as well.

If anyone wants my old Mastervolt ISO Smartcharger 50 amp, I'll send it to you for the shipping charges. The charred area I found suggests the problem could have started at the 110v fuse holder but there are a couple components that are a bit melty too. Not a good sign that an Electrical Engineer friend of mine turned it down (partly because its output is only marginally more than his existing one that works fine).

Anyway, Nigel Calder recommended a Victron charger for my application. My TPPL AGM batteries want a certain charge profile which can be programmed on some chargers, including Victron.

You'll want to be sure that your smart charger profile reasonably matches the needs of your batteries. Some chargers sense when batteries are not being used and cycle off for days at a time before kicking on absorption and float again. Some batteries are happier if not on continuous float. Ahh... here it is... "storage mode":

FROM VICTRON:
Less maintenance and aging when the battery is not in use: the Storage mode (see fig. 1 & 2 below)
The storage mode kicks in whenever the battery has not been subjected to discharge during 24 hours. In the
storage mode float voltage is reduced to 2,2 V/cell (13,2 V for 12 V battery) to minimise gassing and corrosion of
the positive plates. Once a week the voltage is raised back to the absorption level to ‘equalize’ the battery. This
feature prevents stratification of the electrolyte and sulphation, a major cause of early battery failure.

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I suppose the bigger and fancier the battery bank the more trouble it is worth going through to make its charging environment perfect. A lot of people just get the cheap ones and replace them often and that seems to pencil out for them.

I'll see how it goes with the Victron I have on order. In the interim, I'm drawing about 8 amp-hours a day from my 725 A-H house bank with the fridge off, and have plenty of solar each day. I want to get it done soon because we're settling into the rainy season after amazing good weather this summer. Noooooooo! It can't end!