Introduction: 12 V DC Battery Box.

This is my multi use battery box to supply a 12V supply or 5V USB supply when out camping .
It can be used for anything that runs off a 12V cig lighter socket, standard SAE connection or USB connection.
Idea for charging phones , lights, fish finders etc etc.


Duratool water resistant case.
4 way fuse block ( non LED to prevent parasitic drain of battery.
12V 7Ahr or larger 12Ahr rechargeable battery.
4 X toggle switches
12V volt meter
12V SAE Panel connector
12V cig lighter socket
12V USB dual socket 1A/2A
Crimp connector s
In Line fuse holder.
Earth bar
Fuses ( standard blade type )

Step 1: Decide Your Connections for Accessories

This all depends on what you require.
My main requirements were for the following.
A cigarette lighter socket for a standard cigarette plug.

A USB socket to supply 5V supply for phones/tablets/map reading lights or anything else that runs off a USB connection.

A SAE Panel socket to supply anything with a SAE connection.
I also use this as a battery charger connection.
For this I use a battery tender 800 Milli amp hr charger.
This just plugs in to charge the battery up to full capacity.

A voltmeter to show battery voltage.
This gives you a rough idea of how much battery power is left.

Each item is switched individually using a toggle switch.

Step 2: Battery Choice

I've used a 12V 12Ah rechargeable type. It fits nicely in the center of the box , giving just enough room for the switches and components either side.
You could also use one or two 7Ah batteries depending on your requirements.
The wiring diagram is a guide to how I did mine.
One main in line fuse and four individually fused circuits.

Step 3: Putting It All Together

It's best to dry run your layout before you start drilling and fixing.
Each of my connections and voltmeter are individually switched for convenience.
I installed one main in line fuse off the positive terminal terminal of the battery.
This runs to a separate fuse box containing a single busbar connection and 4 individually fused outlets,one for each of the switches.
I chose not to use the type with a led light indication to avoid parasitic draw from the battery.
A separate earth bar is used for the negative side from the battery.
High density foam was used to pack out all the spare space and keep everything snug.