OP here. Very interesting discussions!!
I will take another hard look at my controller -- I am pretty sure it is molded onto the back of the panels with plastic -- not designed to be removed. It would take a lot of courage for me to cut it out and move it to the battery. What if I mess it up? These suitcase panels are not cheap.
I think I understand, though, why the manufacturer designed a less-efficient "all in one" system. The goal is a consumer-friendly "plug and play" portable solar panel -- nothing to do but just hook up the cable. The more complex the system, the greater the sales resistance.
I know that my 12.7 daily reading is not a full 12.8, but the proof of the pudding is in the eating, as they say. We routinely boondock for a week at a time, using the solar panel to top up the battery to 12.7 every day. We have never lacked for power. (Admittedly, we are very frugal.) So the panel is providing us with more than mere maintenance -- the power system does just what we need it to do.
If it were doing nothing more than maintaining the battery at its then-current charge, we'd gradually run out of power during the week. We don't.
I like the idea of chopping up my cable into pieces and attaching as many segments as needed. But I'd still have to transport all of the pieces.
