Also keep in mind if your LV battery is dying all the time, you are going to seriously shorten its life. Those batteries are not designed to be deep cycled, and deep cycling it could easily shave 500% off its life if you do it all the time. Also, it is not clear how charging a dead battery with the DC/DC converter affects the life of the converter. It's well known that charging a dead battery frequently with an alternator can kill the alternator, and so it stands to reason doing the same with a DC/DC converter could damage the converter.
The correct answer is to get the technician to fix the issue. I think we have it fairly narrowed down. Water pump, software update, hot fuse. Those seem to be the three fixes so far, so look into it and fix the issue.