Thought I'd post this because I see these "multi purpose" battery
boxes are coming down some in price... Link to one site
I bought one four or five years ago and really like it, mostly for the built-in 12v plugs. Real handy for airing up the trailer tires
when hitched since my little portable 12v compressor won't reach that far back from the dashport. Also good for other 12v uses...plus, the external posts let me hook the battery
directly to a charger without having to open the box.
I will say that the "monitor" quit working after the first couple of years, but I usually use a simple reader that plugs into the 12v socket anyway.