Here's what I wanted out of this project:
Reasonable battery capacity, ability to recharge itself, reasonable audio fidelity, rugged durability, ability to charge/ power other devices [music players, phones, raft inflaters].
As far as I know, so long as I don't let the battery go flat for too long this box should be able to provide electricity and music for years without ever plugging it into the grid.
Step 1: The Box
Other options I considered were Pelican cases, tool boxes, and suitcases.
Step 2: Ingredients
20mm Ammo can.
Pyle marine audio deck. [inputs for 1/8" mini, SD card, USB.]
West Marine water tight, 3 gang, 12v outlet.
A couple of brass bolts. [For aux. power out.]
Super cheap automotive LED accent lights.
Harbor Freight jump-start kit. [Battery, charger, light switch, power switch, battery meter.]
Harbor Freight solar battery charger.
I chose the deck with a couple of things in mind. There is no spinning media [read efficient], it has a weather band tuner [many a traveler has been saved by NOAA's warning of incoming foul weather], it was relatively cheap [$75], it has a variety of inputs for a variety of purposes, including a SD card slot [awesome], and it's supposed to be resistant to wet conditions.
The battery that I harvested from the jump-kit was a 17Ah [Amp hour] SLA [sealed lead acid] and was the perfect size to fit between the walls of the ammo can, below the speaker frames, and left enough room to add a second battery on the day I decide I need more energy capacity. Sadly, after the year or so that this project sat still I let the battery go flat and it crapped out on me [I blame cheap HF equipment]. I had to buy a new one with 18Ah.
[Caveat, I love/hate harbor freight. If it's too cheap to be true, it's probably not worth the time or money you spend. But it IS a hacker's paradise.]
Step 3: Faceplate
Once I got all of the layout done it was time to wire it all up. Yet another challenge that would not have made for good TV. Lots of decisions here; what does and does not go to the mains switch, what goes in parallell/ series, how to make the solar panel and wall charger not blow each other up [fingers crossed]. The photos show the complexity. Your results may vary.
Step 4: Speakers
Once I had a smaller pair, that would work in this case, it was a matter of cutting one big hole and four small holes for each speaker. Measure carefully, mark clearly, cut slowly, and mount with confidence.
Oh yeah, install the foam gaskets before mounting.
Right now I'm debating how well I want to seal the interface between the speaker and the wall of the box. On one hand, a water tight seal would be great for foul weather and the occasional dunking. But with the lid closed I fear barometric and altitude changes might damage the speakers, so a less than perfect seal might be an advantage.
Someday I will find, and invest in, a two-way check valve to regulate internal pressure without compromising watertightness.
Step 5: Mounting Frame
Here I [finally] went back to my original inspiration: Joe's box. He had used a wooden frame to hold the battery and mount the faceplate. Thanks Joe. Your inspiration saved me from myself.
Again careful measuring wins the day. Find the position of your speakers relative to the sides, and cut away the floor plate where it will need to pass by the speaker frames.
I chose to "swiss cheese" the floor plate. I'm not sure if it will help, but my feeling is that it will provide a little air and cooling to help prevent the battery from overheating.
The rest of the frame I glued and stapled together. I used screws to attach two more pieces of wood that will help lock in the batteries. That way, if or when, I decide to add a second battery, I can move them to where they will be needed in that case.
Step 6: Battery Mount
You know, my old boss hated plumbing strap. And he passed that prejudice along to me. However, there are times when the the "right" solution would require far too much fabrication, time, and money, and a little bit of that ugly, holey [unholy], curly stuff does just the trick. Careful work here will keep you from wanting to hide this piece from view.
But the coolest part is that piece of white plastic sticking out the side. The plastic is Polyethylene [HMPE] like what milk jugs and flexible cutting mats are made of. I cut it to be just long enough to wrap three sides and a little extra to tuck back down the side. What this accomplished is two-fold. It Isolates the battery from the metal sides of the box [I hear that's good]. But the coolest part was that it made the perfect, spring loaded guide that holds the whole assembly snugly inside the box. With it I can turn the box upside-down and the frame stays put. Cool!
Step 7: Final Assembly
Step 8: Enjoy
It works on it's side, or upright, though everything is upside-down when on it's side. Upright focuses the sound in the direction of the listener [efficiency] and still functions as a spare seat in camp. So That's probably how it will work most often.
Step 9: Not Pictured
I mounted the solar panel to the inside of the lid with velcro... magical stuff. I intend to add a couple velcro straps to the system so, perhaps, I could mount the panel to a tent pole or nearby tree.
I will also add some velcro to the inside walls of the mounting frame to hold the accessory cords, charging cables, and what-not out of the way.
A paint job is in question. But for now, I'm going punk rock.
There you have it; My first instructable!
Special thanks to Joe who inspired the project and then the work.