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Portable Power Units - homemade battery boxes

23K views 0 replies 1 participant last post by  Illuminum3415 
#1 ·
Hello,

My first thread here so I hope to make it count. Been reading up on DIY battery packs and feels I could improve on the idea bank a little by posting my designs. However, a big difference is portability. I could easily have created something that could be hauled around between the garage and up the gangplank into a pickup truck, but that wouldn't really be portable. :thumb:

Back in the days when I was a student, I was blessed by the privilege of not having to work between classes. :sleep: I took up the frequently misunderstood hobby of dumpster diving for electronic components. In the process, I started making a number of different projects. Among which is the concept of a portable battery. I needed a portable power solution for me to test the various components I retrieve in the field in order to determine whether that component is usable. A portable multimeter can be commercially bought, a power supply couldn't.

PPU-1: Experimental power supply: EPS-01
The idea is simple, build something that can deliver 12V [nominal] anytime anywhere along with a regulated stepdown that can grant me any volts below 12V and allow 500ma of output without dumping heat [switch mode over linear]. Subsequent power packs went digital on the meterand added a 12V regulator feature for exact 12V, not nominal 12V... to take place of wallworts on dedicated 12V devices.



The EPS-01 was my first crack at coming up with a portable variable "bench" supply for me to conduct testing with while I'm out of my shop.

The top connector goes to the BatteryMINDER charger, no battery charger is integral to the portable supply. Operation is simple.
Four switches makes it a rudimentary system:
The left upper switch is a Lamb Subminiature SPDT ON-OFF-ON Switch, it determines whether the battery is connected to the charger [down], isolated
, or to the load [up]. Both switches on the right are disabled until this switch toggles up.
Left bottom switch links to the analog meter, which operates both as a battery meter and the adjustable output reader.
Right upper switch engages the variable power supply [LM2594 I think]
Right lower switch is just battery direct output, connecting to the board mount fuse holder

The extra wires on the control panel are alligator leads I left in it for field use. The battery used is a UB1270 :)

The control panel is mounted not using screws but velcro [you'll read about it in a minute :upsidedown:] to ensure that the enclosure retains full integrity.

The power supply was dismantled following graduation and scrapped for parts. The enclosure and battery then became "PPU-2"

PPU-2 "Luigi"

I became a member of Brevard Astronomical Society in 2007 and found myself dealing with alot of power related problems. I've never been much of a fan of astronomy but more in specialized illuminations. During many of our public-welcome star parties, once awhile we will set up posters that needed to be illuminated [by red light or low intensity white]. Doing this using alkaline batteries was cost prohibitive. Therefore these two PPUs were born.



The upper one was an easy build, inheriting 80% of its parts from the PPU-1. An Exeltech 1A 3-stage charge controller was built in, requiring only to be plugged in with an IEC compliant AC cord after use. A standalone Voltmeter was incorporated to monitor the battery during charge or discharge and remains a tradition in my builds. Output is in two forms: Banana and cigarette plugs.
On one beautiful outing, it caught a friends attention and I sold it for material cost. Last I heard he forgot to turn the meter off during storage and the battery died a very slow death [down to about 3.2V]. :(

PPU-3 "Mario"

Mario was an oddball, I don't remember the exact operation because it was dismantled within a year following rain intrusion and corroded contacts. It used two UB1270 batteries in a unique configuration that allows one or both batteries to be connected or disconnected from the load. Output came in the form of a cigarette socket and a 12V regulated line for noninductive loads up to 15W. I believe the converter replaced the wallwort of a plasma ball at the time.
The system was setup to have a 12v load not exceeding 50W, and was capable of running the load on batt 1 while charging batt 2 and vice versa. It was a very complicated approach and improvements had to be made.

The space in the back stores their proprietary chargers, making them easy to transport, store, and user friendly. "Mario" held its own BatteryMINDER charger quite well.

PPU-4 "Sol Harvester"

I loved and will always love my old Samsung flip phone. The thing is tough as nails and have wonderful battery life. However, my brother [Apple fan] convinced mom [our family plan provider] that Iphone 4S is the way to go. From then my scope of life widened, but so were the hassles. To maximize productivity, this phone has to be charged everywhere it goes. A new feature was envisioned for all new PPUs from this moment: USB output.
It didn't take long to figure out that simply connecting the power lines and leaving the data pins open will not charge the iphone.

I borrowed some critical need to know information from Ladyada here: http://www.ladyada.net/make/mintyboost/icharge.html and designed the PPU-4




It was around this time when I salvaged five 10W solar panels and quickly went to work on various energy harvesting ideas. Most of the panels went into direct driving a row of PC fans [also salvaged, varying in size] to cool the lawn tools shed during the hot summer days. One set of fans brought air in from one window while the other pulls the air out. Worked well keeping the gasoline smell to a minimum and the stuffiness out.
PPU-4 was based mostly as a solar charge controller for USB devices, but I added a pigtail for the BatteryMINDER.

The design revolved around two systems: a PV charge controller and a DC-DC Stepdown. Battery is still a UB-1270

The controller I used was taken apart and hardwired into the circuit. Since the instructions specify how to connect/disconnect the controller and in what order, I added three switches to accomodate the disconnect process. In return I can connect the PV directly to the PPU-4 without a fuse block or disconnect and have charge control plus LVD for the load.
Source: http://www.allelectronics.com/make-a-store/item/SCN-1/3A-SOLAR-PANEL-VOLTAGE-CONTROLLER/1.html

The setup worked quite well as a portable solution and is still in operation today.:thumb:
The voltmeter is engaged when the battery toggle is on. Battery has a 10A fuse while the PV has a 3A fuse, both GMA. Banana jacks is incoming PV, 40W max. USB is fed by a pair of Non-Iso/POL Converters from the Murata OKI-78SR series, independently wired to the panel mount USB sockets with a 5.1V zener overvolt protection.

Converter: Digikey: Murata OKI-78SR-5/1.5-W36-C
USB: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_144813_-1
Zener: 5.1V 2%, salvaged NZX5V1A

The USB sockets are configured to charge an apple product at an 1000mA rate, and it works very well juicing up Iphone 4, 4S, and Ipad Gen I.

Some of you I'm sure are still wondering how the panel is mounted, here you go:



A pair of C channels and alot of velcro. C channels are held level, measured, then velcroed in first, then the panel drops on on top, also velcroed. It looks cheap, but I had to pry the panel out of the enclosure with a screwdriver. I can confidently hand the power unit by the panel and not worry about a thing. This way I can dismantle it and return the ammo can to storage ammo if needed.

PPU-5 "Sunny Boy"

This one was concieved during an unusual year of rolling blackouts in the area, whether it was from meteorological or man made causes. For the reason I opted for a high visability enclosure and selected an Attwood boaters dry box. The box turned out was not waterproof in the least bit, but it held well in moderate rain.









Yes, my toe is in the second picture. :eek::
Charger input is on the left, slightly above it was the voltmeter, complete with its own toggle masked under the BatteryMINDER charger cord. To the right is a pair of standard toggles. The left one switches the battery the same way as PPU-1: Load [up], Isolated
, charge [down]. The right switch gives the option of the 5V output. Since the converter draws current at no load [~15mA], a switch had to be added to prevent drain. The USB connector is located between the 12V sockets, configured for 500mA charge rate.
I upgraded from UB1270 to UB12350, this became the standard battery for all "homebrew" creations.

Converter: Recom R785.0-0.5

Wiring was a mess because I was using salvaged solid conductor 16AWG outdoor wire for this project. While I'm sure the sockets can provide 10A each in a pinch, I designed each socket to source no more than 100W and spec'd the wires from there.
This battery box worked wonders not only during outages but also during campouts. Where it ran a pair of 13W florescents that lit up the party tent and the sleeping tent wonderfully well. The box has to stay in the sleeping tent as it nearly walked away once.

Lights: http://www.walmart.com/ip/Bayco-Fluorescent-Work-Light/16652303

The unit weighs about 40 pounds, and pushes the limit not for me but for everyone else in the family to bear comfortably. Therefore I decided that all portable units will not exceed 50 pounds and that pretty much limited me to use 35AH batteries. I had a mount built to secure the battery but replaced it with shipping peanuts to reduce weight, worked well.

PPU-6 "Blue Boy"
A colleague asked me if I can build something similar for his telescope. He previously used a 15AH jumpstarter to provide the tracking motor but once the battery went kaput last month he couldn't replace the battery without "trashing" the jumpstarter. So he asked if I can come up with something that makes battery replacements easier. I was puzzled by this request but like a good friend I built something for him over the weekend.

Started with a S&W gun case and ended up with something like this







As simple as I can make it: When the switch is on voltmeter is on and the socket is live. Socket is fused at 10A, GMA panel mount. Internal foam is cut as needed and the rest gives the battery some insulation and snugs it from sliding.
Two UB1270s in parallel. 14AH, as close as I can get it. Charging goes through the same hole. I bought an attwood 1.5A charger/maintainer while it was on sale and spliced the charger output into a male cigarette plug. The battery charger floats at 14.1V so I figured any voltage drop will benefit the SLA. The wires are connected by a pair of color coded Y cables ending with 1/4" quick disconnect connectors. Last I heard he was quite happy.

Charger:

Despite the reassurance he eventually reimbursed me the material cost anyway through buying lunch and what not, why can't gifts just be gifts.

He mentioned if I start making these there might be a market for them. I'm skeptical because nothing I ever come up with ever appealed to anybody, but I started looking over my previous designs and came up just last weekend with a utilitarian looking thing I first called "dumpy"

PPU-7 "Gunners mate"

Start with an MTM 50 cal polymer Ammo can, slap a graph paper template on it, drill holes, wire, test, done. Friday night: design, Satursday: Prototype, Sunday: Completion.











Since the accessory socket came with an L-bracket, I used it as a "staging platform" for the terminal bar. Unfortunately, its also part of the return pin, with such close proximity to the positive terminal I blew a couple fuses while tweaking the "panel end" with tools.
To match the color of the enclosure as well as making it look more futuristic, I went with a green voltmeter I had in the parts bin as opposed to a red. :D:

Voltmeter is independent, as always, toggle up for on down for off. A 15A master SPST controls the output. When the master switch is on, 12V socket is energized, fused for 10A. The toggle switch adjacent to it turns on the USB output. The converter is made by Blue Sea Systems and can provide 2.1A through two sockets. It was apparently designed for apple products and works quite well.

Enclosure: MTM-Ammo-Can-Forest-Green
Voltmeter: http://www.adafruit.com/blog/2011/09/30/new-product-mini-volt-meter/


If I have the necessary parts on hand I can probably turn out 4-5 in a week, but likely I may wind up turning out 3-4, stacking them, and figure out a way to parallel batteries while stacked to convert it into something actually useful for the house. So there you go, that's my contribution for now. if anything new comes up, I might continue then.
Good night, and take care.​
 
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