this is good for all you led underbody people or if you want to install other 12 volt junk (stereo's, whatever) and need to test it BEFORE wiring it all up in your car.

Not really car specific, but here goes:

I like projects. And the only thing better than a project is one that drives you to do another project. So when I ordered the Oznium LED underbody kit for the Scion tC, I knew I would need a bench testing power supply..You need to test those lights before installing, right? Running out to the garage to hook it up to the car's battery? Pshh whatever. It's cold out there and I'm doing my test work indoors for the winter. I was going to build a power supply so i could stay all warm all cozy during my project.

I would have used a PSU from a crapped out computer but that blew so I bought the one on the Oznium site. (this one http://www.oznium.com/power-supply) The only problem was the suggestion to use one of the molex hard drive power connectors and to short out another wire to get power. Not good enough, seems goofy...I needed to beef that up to a reusable tester.

Note to the Oz folks..the description on the site says to short +12V and black for -12V. That's actually incorrect. The black is Ground, so 0 V. Anyway, here is how you can take that Computer ATX PSU (or a similar one) and build a multi-function, quick disconnect power supply.

You will be able to test varying voltages, firmly clip your wires with binding posts instead of holding them with your fingers..and add a status LED (so you know when the PSU is actually ON).


Notes: Do not touch the capacitors as they may retain a charge, do not leave this plugged when working on it. You assume all risk in this project. I am just a regular joe, and this is what i did. No one is telling you to do it. Electricity can kill! No one is even saying this is the proper way to do it. If you have any trepidation, just go to Radio Shack and buy a bench test power supply for $100.

Project Tools:

Soldering Iron
Solder (duh!)
Binding Posts (5, but the usually come in even packs)
Heatshrink tubing
Electrical Tape
1 Led
1 330ohm Resistor
Hot Glue Gun
Wire Ties
Screwdriver
Wire Cutter / Stripper
Drill



*** Make sure the PSU is NOT plugged in to live juice. You know what?? Just remove the power cord for now..I don't trust you one bit. ***

1 - Open the ATX PSU case. If memory servers its about 4 screws.

2 - Cut the Molex connector meant for the motherboard. (I left all of the other computer harddrive connectors attached..who knows, i might want to test an internal accessory in the future)

3 - Separate and bundle all similarly colored wires together.



4 - Drill holes in the case. You will drill 5 holes (about 1/2" inch) for your binding posts, and a smaller hole for an indicator led. Be sure to capture any small metal shavings. DO NOT LEAVE THEM ON THE CIRCUIT BOARD!



5 - Screw your binding posts in the holes you just drilled.

6 - Solder 1 of each the following colored wires to a binding post, in whatever order makes you happy:
a) Red - Thats your +5V
b) Black - Thats your Ground
c) White - Thats your -5V
c) Yellow - Thats your +12V
d) Blue - Thats your -12V

7 - Solder a Green Wire to a Black Wire. That's the power sense..so when you flick the on switch the unit will supply power. You could wire that up to a secondary switch, but i think that is redundant.



8 - Solder the resistor to a Gray wire. Then connect the resistor to the LED. The anode side of the LED gets a black wire.

9 - Heatshrink your solder points.

10- Terminate any other unused wires and wrap with electrical tape.

11- Zip tie in bundles, make it tight and tidy. Make your momma proud.





12- Fit the LED into the small hole you drilled. Use hot glue to hold that sucker in place.



13- Ok, plug the PSU in. When you flick the power button, you should now have an indicator led. Test a 12 volt connection, something..oh i don't know..maybe an LED underbody kit, head unit, whatever using the +12V and Ground connections. The LEDs are nice especially on newer PSUs that are quiet during operation...I really like to know when an item it HOT. On does not always mean on, and neither does Off.

14-Close up your case, but not before marking which binding post is which.

15- Your bench test Power supply can now do the following:

5 Volt (+5v, GND)
7 Volt (+12v, +5v)
10 Volt (+5v, -5v)
12 Volt (+12v, GND)
17 Volt (+5v, -12V)
24 Volt (+12v, -12V)



Oh, so now you can go install your LED underbody kit, or whatever else strikes your fancy.

 

Very cool! I have about a million PSU's sitting around (used to run a computer store) heh... Will have to give this a shot.

 

They do a pretty good job for a lot of stuff. They are already filtered fairly well and can supply a decent amount of power. Good write up!

 

wow man thats awesome gives me idea. i wish i knew this before i um. . .blew it up. .