Recently I’ve just got back into camping, getting away from the city and finding new areas in the beautiful state of Arizona. I do however still enjoy some of the luxuries of home like powering my phone, charging DSLR batteries, running a small USB powered fan, and running some hanging USB powered lanterns.

To power all this stuff I’d need something capable of supplying me with enough juice to last more than a couple days while still being portable enough to quickly pack into the Jeep without taking up too much space. Some quick searching found some diy power boxes housed in an ammo can. This is where my story begins.

Looking into some of the retail devices that fit this bill you’ll quickly see that they’ll start around $200. Many include dc to ac converters for 120v output; I don’t have any 120v devices to power while camping so I won’t need an inverter. Goal Zero seems to make some popular products that get good reviews, but I’m positive we can build something for less that has plenty of power!

Build Supplies (no affiliate links):

Ammo can from Harbor Freight $4.99 with coupon

16 gage wire Lowe’s -$5.89 x2

12v 10ah Sealed Lead Acid battery x2 -$40 –ebay

Crimp connectors- $7.00 Amazon

Switches- $5.00 -ebay

Fuse 15a & misc -$5.00

12v dual socket with battery voltage meter and USB ports – $11.99 Amazon

SLA Battery charger $11.99 Amazon

Anderson Powerpole connectors 10pair ebay -$6.00

Tools:

Drill and bits

Cheap wire stripper and crimper

Hand file with curved edge or a step bit 1” (faster with step bit but not necessary)

Utility knife

Basic electrical wiring know how

Below is my best attempt at a wiring diagram for the unit. There’s a jumper wire from the second switches accessory out to the voltage gage. All other connections are daisy chained.



Note that in this build we will be using two batteries running in parallel, in your build one battery may fit your needs. This battery was chosen due to the narrow width of the ammo can approximately 3 3/4th inches. Two batteries can fit standing on their sides. There’s an inline 15amp fuse from the battery right before the Powerpole connector.

To start the project remove all of the gauges and plugs from the 12v outlet thingie. This leaves you with a flat plastic bezel that they slide into. I used this as my template and traced the outline of the holes with a sharpie marker. Removing the plate after I had the holes were traced I used the biggest drill bit I had and drilled a hole. The hole wasn’t nearly big enough so I used a hand file and utility knife to help make the holes big enough for my two ports and battery gage to fit through. This was probably the longest part of the process as I wanted to ensure I didn’t break the plastic lid etc. once the gauge and ports were installed I secured them with the screw on nuts provided.



Next we install two switches. One will be the master power switch, this one switch will turn your power box on and off. The second switch will be an intermittent switch that we will use to check our battery voltage; when toggled on the voltage meter will activate. This prevents the voltage meter from draining the battery, as you will only need to check battery voltage from time to time.



With our switches and gages/ports mounted its time to wire the box. For the most part the wires are all daisy chained which makes this a breeze. The master switch allows power through all of the wires past the switch. The Anderson power pole connector allows me to connect the batteries to the charger. Take your time when wiring, keep your work neat and tidy.



At the time of the build I only had one 12v 10ah battery, the second is on the way. With two batteries in the ammo can I’ll have 20ah of total power. Enough power to charge my phone several times over, and my DSLR batteries too. The power box is small and doesn’t take up much room in a car; it can also be be charged with a solar panel while you’re out camping. A power box like this is also popular with preppers, and anyone else that’s off grid for long periods of time.

To charge the batteries I went with a super cheap SLA battery charger from Amazon. I modified the chargers output to also have Powerpole connectors. The Powerpole connectors are easy to clip on and off and are designed for high current/amperage use. To figure out capacity of the batteries I’m using this handy table from somewhere on the web.



Now that the build is finished I’ll have to follow up with an update after my first trip with it.