The battery maintainer (maintenance charger) can be placed outside of the battery box, if the leads between battery and maintainer are long enough, or are extended.
They commonly have a plug and socket in the leads (my Schumacher does) so that the leads can be left attached to the battery (such as by those ring terminals) and the maintainer just plugged into them when desired; it would also allow different ends (permanently installed leads, battery clips, etc) to be used with the same maintainer.
I think a nice setup would be a receptacle mounted through the battery box wall, so the leads could be left attached on the inside, and the maintainer plugged in on the outside when desired, without even opening the box. In this case, it might be a good plan to also mount a switch through the box wall, so the receptacle isn't always live with battery power, and to put an inline fuse in the lead to the positive battery terminal. I haven't done this yet.
1979 Boler B1700RGH, pulled by 2004 Toyota Sienna LE 2WD
Information is good. Lack of information is not so good, but misinformation is much worse. Check facts, and apply common sense liberally.
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