Fascinating reading. 3 failed Victron MPPT Controllers on two FWCs, along with your characterization of the problem, looks an awful lot like faulty wiring design or error by FWC. FWC needs to get involved - there may be more owners with this problem.
acmedave, the FWC dealer in Portland and Seattle, Mule Expedition Outfitters (dasmule.com), does custom mods on FWCs and other overland vehicles. I know they work with the folks in Woodland. If it's feasible for you to get to Mule, see if FWC can have Mule troubleshoot on their behalf.
Wiring is vastly improved from my previous 2005 Eagle, but it still looks like there are a lot of custom connections. I hope FWC is moving toward a relatively small number of wiring harnesses with connectors. Wire and connectors, even if unused, are cheap relative the cost of labor for custom wiring (and especially troubleshooting).
If they don't have already, FWC needs an in-house expert on wiring. Solar will continue to change rapidly, and the Sure Power 1413A already needs to be replaced as standard equipment (DC-DC, smart battery separator, or a smart lithium battery).
A few weeks ago, I had a very interesting conversation with whomever was answering the phones on Saturday. FWC is still on a dozen or so Excel spreadsheets for each build, hence the $250 post-order change fee. He also commented that the permutations of models and options results in over a million possibilities, but they are working hard to get onto a manufacturing software platform.
Another interesting comment. The majority of buyers have been older and often retired but there is a shift to more buyers in their 30s to 50s. FWC is working hard to increase sales in this group. Also, most owners aren't like us, the ones posting here. Not too surprising. Engineer-itis and geek-itis affects a relatively small part of the population. Maybe 80% or more of buyers will not make any changes to their FWCs over the life of their ownership.
Edited by Jack, 22 June 2020 - 04:46 PM.