Nic, You asked for an ammo can 12v power station build walk thru.....this is about the best I can do.....at the end is a generic Amazon Parts List the stuff I mention.
First you need to decide what you want it to do. Just to be a USB charging station? A combo power station with USB charging as well as to power a HAM radio? Do you want it to be charged by a separate battery charger only? Or do you want it to be charged by solar panels? How much power, or amps, will you draw from it? The more you want it to do, the more stuff you need, the more it will cost, and the bigger the enclosure you will need. After you decide on what you want it to do, you have to figure out what enclosure you will use. Using a FAT 50 GI Ammo Can like I did, also limits the size of battery you can use. To help you decide on the enclosure, you need to decide on how much energy you need. Since this will be a 12v system, look at the physical size and the AH rating of the battery. Bigger AH is better.....as long as the battery will fit..... Gonna make some assumptions for this walk thru... FAT 50 GI Ammo Can USB Ports Cigarette Lighter Socket Anderson Power Pole connectors for HAM No Solar Charge Controller SLA battery
It will be an external access build. 10-15 amps total draw. I use the 1” modules for my builds.
If you get this set, and use each module, you will have to 5 holes in the lid of the ammo can. Because for powering a HAM radio, you will probably need Anderson Power Pole connectors. You can get them in a 1” module as well.
But, if you replace the Voltmeter and USB charging modules with a combo module, you only have to drill 4 holes.
To drill the holes in the ammo can lid, I drill a pilot hole with a regular 1/4” drill bit. Then I use a step drill like this one to open it up to 1-1/8”:
I then use a round file to clean up the burrs. As you can see here, four holes don’t look bad on a FAT 50.
I placed the round nuts from the modules on the lid in several configurations. Because my goal was to have 3 USB charging Modules, and 1 Cigarette Lighter Socket, I decided on a straight line. When I build my next FAT 50 with external access, it will be a combo. And I already know I’ll do two above and two below the handle. Towards the corners.
Before you drill the holes, ensure you don’t get too close to the edge so that you avoid the angled metal that holds the gasket. Don’t want to interfere with the modules nut.
My next one will have the Power Switch and USB/Voltmeter modules above the handle. And the Cigarette Lighter Socket and Power Pole modules below the handle.
But you gotta figure out how YOU want them arranged.
But Wait! There’s more. If you don’t want to drill holes in the lid of your ammo can, you can cut a piece of this plywood or lexan.....I used lexan with one, trimed it to fit the body, then put a bead of hot-glue inside at the depth I wanted it to be.....just deep enough to clear the modules when the lid was closed.....this kept it waterproof.....
I recommend using a shelf as is much easier to reconfigure later, or even start over without having drilled hole in the can itself.
After you drill and de-burr the holes, you get to play with deciding on the arrangement of the modules.
Once you have them arranged the way you want, insert them and screw on the nuts to lock them in place. But Wait! There’s more. If you don’t want to drill holes in the lid of your ammo can, you can cut a piece of this plywood or lexan.....I used lexan with one, trimed it to fit the body, then put a bead of hot-glue inside at the depth I wanted it to be.....just deep enough to clear the modules when the lid was closed.....this kept it waterproof..... So everything described above also applies to drilling a shelf for inside the can....
Next, you get to start wiring it all up...But first...if the assumption is 15 amp max total draw, you can use 14ga wire. But you need 12ga wire for up to 20amp max total draw. If you need more than 20amps, this build will need some important changes
I choose to use “Flag” connectors to save some length at the bottom of the module. See the picture above that shows them. Here is the basic wiring diagram for the modules:
But if you choose to use a Power Pole module, you will have to take into account that it has 2 “+” and 2 “-“....here is the back of that module:
You can see it’s different from the other modules. However, if you want to simplify the build, you forego the Power Pole Module. Just use just the 4 module that come in the kit. And then you can then get or make various adapters that can plug into the cigarette light socket and give you Power Pole or any other kind connectors on the other end. This is actually how I use and charge mine. I bought a few of these off of Amazon:
One is in each can just like it came. Others, I cut the terminals off, and replaced them with the type of terminals I needed. Like one has 5mm x 2.5mm plugs so that I can power my security camera system during a power outage without firing up the genset. One tip: I use a small screw driver to pop out the switch from its module. Then I feed its wires and connectors thru the module, and then connect them to the switch. Makes it much easier. Ok, now that you have the holes drilled, modules installed, and wired, you’ll need to connect it to the battery...... But First....need to talk about batteries..... Obviously you want the most capacity you can fit in the can...taking into consideration how far down the modules and wire ends extend down into the body of the can. Basically you’ll only be able use one of two types of batteries. SLA, Sealed Lead Acid....
Lithium.... SLA is the most common choice. It’s the less expensive choice, and chargers for them are more common. They have drawbacks though. They’re heavier. You can only use 50% of their capacity without harming them. They have a shorter life span.
Lithium is the better choice. They are far lighter than SLA’s. For the same size, they can have higher capacity. You can use up to 90% of their capacity without harming them. Their life span can be 3-4 times that of SLA’s. But they too have drawbacks. They cost twice that of a similar SLA, sometimes more. If you over charge them, or drain them to low, they will not only be ruined they can catch on fire. They require specialized chargers. They can’t be discharged or charged as fast as SLA’s can without harming them. BUT....if you get a lithium battery that has a built-in BMS (battery management system), the BMS will protect it from overcharging, undercharging, short circuits, overheating, etc....
Now to the next battery issue....running two batteries in parallel....it a great way to get more capacity in the limited space of an ammo can....but there are drawbacks.... When left alone for extended periods, two batteries connected in parallel can “teeter-totter” and discharge each other unless they are perfectly matched. And it’s rare to get matched batteries off the shelf. You need to use an analyzer on several, and then select the two that have matching results. Most people ain’t doing that. So you have to keep them on a charger, or have a disconnect to electrically separate them when not in use or charging. Mine, in the pictures, has a STDP switch to do this. You also have to use the same length of wires. This is far more critical for Lithium batteries.
Wires have resistance. Not much, but they still do. And Ohm’s law always applies. When you have two batteries in parallel with un-equal lengths of wiring to each one from the rest of the system, the battery with the longest leads has more resistance between it and the system than the battery with the shorter wires. This means it will provide less energy when discharging, and receive less energy when charging. This combination will reduce its capacity over time, reducing its lifespan compared to the other battery. Eventually it will actually cause the other battery to overwork, and ruin it too. All that to explain why you need use exactly the same length of wires connected to parallel batteries. And to either always keep them on a charger, or have a disconnect between them each, and the system.
Now back to the build.
After you place the battery in the body of the can, I like to cut up closed cell foam, used in a lot of packaging, to surround the battery to keep it from moving around. Alternatively, I have used a lot of Velcro on the bottom of the battery and the inside bottom of the can. Now you need to connect the inline fuse between the battery and the power switch. Then you can connect it to the battery. It sounds far more complicated than it really is....
Figure out what you want before you order parts... Drill holes in lid of the can, or the shelf...
Insert the modules... Wire it according wiring diagram... Not that it’s built, you need to regularly monitor it, and charge the battery.
Remember, SLA and Lithium batteries require different chargers...
Generic parts list:
Power supply to keep it charged without solar... $8.80
Charge controller... $15.87
Panel with switch, voltmeter, USB ports, and cigarette lighter socket... $18.54
Optional USB fast charge module... $11.99
Power pole connector module... $25.49
Fuse holder options... $7.99 to $11.99
Optional terminal blocks... $10.94
Electrical connector kit... $10.62 - $15.99
SLA Battery 12v 15ah... $32.99
12ga silicone wire......$22.98 If you will only have low power draw, 14ga is cheaper...
Step drill bit.... $12.99