Camper Power: 12 Volts Forever!

Ok, so we all agree that the camper will have its power needs met by 12 volts. That's standard automotive voltage, so there's lots of accessories out there that are made to run on that. It's a no-brainer.

Down the road, I want to have a gel cell or marine battery: something that will get me 12 volts and be rechargeable and can be run down to near zero without ruining the battery. Meanwhile, I can go alkaline with 6 volt latern batteries. I made a 12 volt battery pack using these and they can power some lights and even a decent audio system for a long time.

Sooo.. if 2 batteries in series gets me 12 volts, then 2 batteries in series, in parallel with 2 more in series will get me 12 volts for a really long ass time. So I knocked this out like this:

I modeled up the box and printed out the flat pattern- cut out the metal, etc, etc..

Added some mounting ears and ta-daa

Thin sheet of copper with a 1:1 printout of the traces needed to get 12 volts
 with tons of milliamp hours  from four 6 Volt lantern batteries

Bond it to some electrical grade fiberglass

Cut out and discard the copper that's not the traces

I then take 2 strips of copper and slip some shrink sleeve on them,
 and then toss a rivet at the end to form a via.

I then lined the base plate with a sheet of fiberglass. Note the rivets
passing through the copper. I don't want these or my copper strips shorting
to the base plate.

I put the sides on then lined them with more fiberglass to take up some of the gaps.
I added  some panel mount banana jack receptacles for my terminals.

I removed a section of the front of the box so that the terminals can be mounted in non-conductive
fiberglass. I drop in my batteries and Bingo! !2 Volts DC

Now for a lid. I like these cam lever action latches. I use them in the escape hatch, too.
I draw out my idea on a sheet of scrap aluminum.

I cut the panel and milled the slots for the latches to grab onto the lid.
I riveted the latches to the sides of the box. The springs of the battery terminals
keep everything snug.

Popped one latch just for a detail shot

There it is. The little thing above it is my 12 Volt, 2 battery pack.
It's made so that it can be clipped to a belt for super portable 12 volts. It also requires
#10 ring lugs on your cabling and then nut it down with the black nobs. The big battery back uses the banana jack receptacles, so that's a lot easier to put on and take off.

It's rough and maybe not that pretty. Not as nice as my power panel, but this will be stowed in a compartment and will never be seen. Anyway, it's robust as fuck and works flawlessly and there's real beauty to that, too. I only drew out the copper traces and the base plate and wall basic shapes. I tackled this somewhat freehand and just made it up as I went.