Introduction: Ammo Can Solar Boombox
The scope of this instructable is to provide a helpful tutorial on building this appliance while providing an idea or two on how to tweek it a bit and make it your own. Have you ever been camping, fishing, at the beach, or even in your yard and wanted to hear music and have the option to have your friends connect and play music? This was the start of the idea that evolved into this device that does that and a few other things. Going into this I wanted something that was going to be tough, be highly functional, and yet pleasing to look at. The ammo can boombox has a bluetooth amp and a 1/8 jack audio input as well, it is a car jump starter, 12vdc cigarette jack for accessories, two usb charging ports, a volt meter, a halo led light on the side with dimmer control, and charging via either a standard trickle charger or solar panel, and switches to turn on and off each output for added control.
I have been using this and have found that although I have not actually weighed it, the ammo can boombox is really not that heavy or cumbersome to take with you. The range of the bluetooth with the lid closed is about 10 feet and I haven't tested it with the lid open. I haven't had the opportunity to run it to see how long the battery would last before the solar charger low battery alarm kicks on at low level 10.8vdc. I have connected a portable mini air compressor to inflate tires. I have also connected an external inverter (12vdc to 120vac converter) to charge my laptop.
The adhesive backed LED halo was intended for car headlights but I added it to the end to provide light when carrying the can and walking the trail to the river. I added the dimmer because the halo is very bright and the dimmer was very cheap. I also use a matching shoulder strap I attach to the handle so it frees me to carry more gear.
As to the performance of the sound, I was going to go with marine grade speakers (and plug the bass port/solar plug hole) to keep the can water resistant but settled on lower cost, better performance speakers. Although I could have put focal or morel brand 4" speakers I decided on a lower budget especially since it is, after all, just an ammo box plus I was afraid I might inadvertently damage a speaker since they didn't come with grills and I didn't want to add one. After going with pioneer brand I am thankful I did. I will not try to compare them to reference studio monitors but for the price and size I am impressed at how they sound, and yes, these are loud enough. I have no performance or statistical data for this project because I am not marketing it and aside from gathering the components it was just a weekend project that I wanted to share with the community.
While I tried to target a general audience, everyone here has a wide degree of experience. Some language may be too simple for some or there may be unfamiliar concepts or terms. If you are a beginner, as we all once were, then you can further research it online.
Step 1: Gather Materials
Let's get started by getting the materials together:
12 Volt 10 Watt Polycrystalline 36 Cell Solar Panel Photovoltaic PV 15 Watt Max
1PC 20A 12V/24V Solar Panel Charge Controller Battery Regulator Safe Protection
Cigarette Lighter Socket Splitter 12V Dual USB Charger Power Adapter Outlet Car
12V 9AH Sealed Lead Acid Battery for Emergency Lighting Equipment and ATV's
40A In-Line Car Boat AUTO Blade Fuse Holder Waterproof 12AWG 125V DC
Fat 50 PA-108 SAW Larger Ammo Cans Boxes Army Surplus 100% Steel GRADE2
12V Male Car Cigarette Lighter Socket Plug Connector with Fuse Red LED DIY HM
NEW Cigarette Lighter plug / SAE Battery Tender Charger 2 pole Flat plug 12V Cig
12V Car Round Rocker Dot Boat Blue LED Light Toggle ON/OFF Switch Newly
PIONEER TS-G1045R 4" G-Series 210-Watt Max Power 2-Way Speakers - SJ252
TDA7492P 50W+50W Bluetooth 4.0 Audio Receiver Digital Amplifier Board AUX 12V 24
2pc 12 Gauge 2 Pin Quick Disconnect Wire Harness - SAE connectors
DC 5.5 x 2.1mm Power Male Jack Adapter Cable Plug Connector for CCTV / LED
100mm COB 72 SMD Led Car Angel Eyes HeadLight Halo Ring Light DRL Bulb
misc crimp connectors
paracord to wrap handle
aluminum angle for solar panel frame
velcro for mounting hardware in box
22. misc screws for speakers (I used #10 fine thread)
I did not add the links to the items since items on Ebay or Amazon can be dated and may not be found. I did purchase 95% of the items on those sites so you should be able to search them.Price may vary but total came out to around US$120 not including the trickle charger since I had one already. Plus some items you may find on the list are sold in quantities....but it's fine if you are going to build another one for a gift.
Step 2: Cut the Ammo Can
You can align and layout the inputs/outputs any way you like. I will provide layout dimensions to assist in your design. I was kind of looking for a vintage boombox look so I placed the speakers lower. Although the box lost it's waterproof design as soon as I started cutting into it I still wanted the speakers high enough off the bottom so I can set it on sand or a wet river rock shore. I also did not drill the bottom for rubber feet for that same reason. I had planned to put a rhino lining or spray on rubber for the bottom only so it doesn't get scuffed or so it won't scuff other surfaces. Right now I am just using adhesive backed rubber feet on the bottom.
A few tips on cutting with hole saws....First is Safety. Wear approved safety glasses and appropriate gloves since you will be dealing with metal shavings and sharp edges. I also recommend hearing protection while doing any cutting into the can as it will be loud. I used a 3-3/4" hole saw to cut the speaker holes. The speakers are 4" but anyone who uses hole saws know that the finished size is always larger. It came out just right. I used a cordless drill and set the clutch kind of high so if it bites it won't ruin the can or twist your wrist. I used varying pressure and speeds....faster at first with light pressure to get an even cut and then slower as you start to cut through. You may have to change the angle of the drill so the hole saw cuts evenly. When you are almost through, take it slow. Also, most cordless drill weren't made for larger hole saws so constantly monitor the drill temp and if it gets warm to hot then stop and let it cool so you don't burn out your drill. Using cutting oil where the hole saw meets the metal is optional, I didn't use it since the metal is thin.
I then cut the rectangle shape out where the accessory charging panel goes. Tip: I used painters or masking tape to tape out around 3" from all the way around the rectangle hole you will cut. Lay down about two or three layers thick so when you are running the jig saw you don't scratch the surface of the ammo can with the jig saw foot.....unless you plan to paint the can. I drilled a hole near each corner big enough to fit a jig saw blade and then used an electric jig saw to cut out the rectangle. For all the other holes on the box I just used a 1/8" pilot drill and then used a step drill for the solar charging port/bass port and round switches.
This would be the time to deburr or remove all sharp edges where you cut into the can. Erase any pencil marks used during the layout.
Step 3: Assembly
You can follow my layout of internal parts or make your own. I was going for weight balance, practicality for troubleshooting, easy access to internal parts, room for a small bag of accessory cables, and finally, room towards the top for a possible clear plastic shelf to hold a phone or for expansion of functionality. See the pictures for ideas. I prefer modular design so I went with hook and loop fastening systems (velcro) for all components inside and it has proven durable. I used 2 " wide velcro the full width of the side and bottom where the battery makes contact to the ammo can. It is adhesive backed and very strong.
Once you have all the components laid out to your satisfaction we can begin the next step.
Step 4: Wiring
I have included a basic diagram of how this is wired. In this step make sure you fuse the positive side of the battery before that power goes anywhere and put a fuse on the incoming solar panel power positive side.After that you can add additional fuses to protect wiring or devices as you feel necessary. While I would have added at least one more fuse to the positive side of the cigarette lighter socket. Technically this is not a cigarette lighter socket but rather 12vdc accessory socket because this particular socket is not rated for the actual push in cigarette lighter. If you need that lighter functionality for perhaps remote fire starting then you can find those on Ebay, Amazon, or your favorite shopping source.
Some of my wiring is oversized for the amount of amps I am pushing through because that is what I had. Perhaps in version 2 I will get the right colors and gauge for everything. Typically in a 12vdc system you would use red for 12vdc positive and black for 12vdc negative. Also, I didn't want the solar charger to be in charge of everything so I kept some if the load separate and the trickle charger is charging the battery directly through the cigarette lighter socket. Everything works as it should and perhaps I may get input in this area as this was a prototype.
Finally, since I am putting accessory cables inside I tried to tape any exposed metal contact points or wire ends on the lower half to keep something from accidentally shorting and blowing a fuse.
Step 5: Solar Charging Option
The solar panel is a great option for several reasons. It will keep your battery charged when you are not near an outlet for trickle charging. It can be hat mounted on the ammo can using the velcro tabs. The custom aluminum folding stand will allow the solar panel to be placed in the sun away from the ammo can. You can always get an extension and get even more distance. The solar panel when mounted on the ammo can will provide shade for the ammo can and there is a big enough gap under the panel for you to set your phone on top of the ammo can out of the sun while it is charging.The aluminum folding stand is 3/4" x 1/16" aluminum angle and can be locked in any position 0 to 90 degrees to catch the sun's rays.