Airplane nut

Does anyone know how to convert an old power supply from a PC to power our battery chargers?
I want to save some money and use a power supply from an old PC.

Thanks in advance for any help.

scottm

There was an article about that in the AMA magazine last summer, probably july or august.

Airplane nut

Thanks Scott, I'll look for it.

Matt Kirsch

My Feedback: (21)

I can't say that particular subject has ever been covered here at RCU.

The actual conversion you need to do is going to depend on the power supply you get. I got a very old supply out of a larger server, and all I did was add banana jacks to the +12V and Ground terminals.

With a PC power supply, you would gang several of the +12V wires together, and the same number of ground wires. Some PC power supplies need to have a small load (i.e. a "power resistor" from Radio Shack) connected to one of the 5 Volt lines in order for the power to operate properly.

scottm

Yes, that is what the AMA article said to do.

SilverEagle2

My Feedback: (9)

I did one. The article that I used is at http://www.marcee.org/Articles/PCPowerSupply.htm . The small load only needs to be used on a regulated switching ATX power supply (see article). Another issue is that the amps need to be sufficient on the 12v side in order to work well with chargers like the Triton.

Here is a shot of mine.



The load is being supplied by the 12v, 50W light bulb placed in the umbilical hole with a rubber grommet. (I have the other to the right shown for reference)

I even use the fan up top to cool packs as they are charging since the supply really does not heat up that much.

Also, since some shop tools can run on 5v, I added ports for the 5v as well as the 12.

Hope this helps.

Jason

scottm

The article in the AMA magazine was in the September 2003 issue. It is real simple, you just put a 50 ohm 10 watt resistor accross the 5V wires, and get 13V of output.

Xlogic

Here is an excellent link and how to for coverting your pc power supply. http://www.marcee.org/Articles/PCPowerSupply.htm
I have found out with the newer ATX power supplies you don't need a light bulb or resister just ground the power on line and it works just fine.


Mike
http://www.ncrcf.org

SilverEagle2

My Feedback: (9)

Mike,

Good to know the trick with the power on line.

You will notice that the article that I linked to earlier is the same as yours.

Great minds think alike.

Jason

vicman

My Feedback: (10)

Do a search in RCU for Super Diamond Charger and 12v power supply. You will find quite a few step by step with photos showing how to do it. I have made quite a few for myself and clubmates. Go to raidio shack and get a ciggarette lighter socket and plug. Put the plug on your charger and you have a real clean way to power it at home and the field. It will look good with just a little creative dremell work.

Airplane nut

I wanted to say thanks to everyone who responded to my original question. As you can see by the date on this post, It's been a while since I last looked at my replies. I had given up hope since I didn't get much response in the first two-three days. My power supply still doesn't work, it makes a sound when I turn the switch on, but then goes silent and I get 0 volts. I must have something hooked up wrong, I do have the 10ohm resistor hooked to the 5V line. But I will take a look at the new info you guys posted and let you know what happens, if I can keep from frying myself!!

Airplane Nut!!

Jim Finn

My Feedback: (2)

All I can get is 8 volts from mine. I followed the directions to the letter!

rogwabbit

8 volts?
sounds like you may have a bad power supply to me.
5 and 12 and 3.3 are the voltages you should get from the leads. 8 is not an option...
are you sure you are not measuring voltage across incorrect leads like say... +5 and +12? or maybe -5 and + 12?

Matt Kirsch

My Feedback: (21)

Yes, the black wire of your voltmeter needs to go to a black wire on the power supply.

Measuring the voltage between a +5V and a +12V wire would give you around 8 Volts. Just don't hook up anything like that, or you'll smoke the power supply. -5V and +12V will give you a reading of 17-18 Volts.

Airplane nut

I don't know what I'm doing wrong, but I can't get mine to work at all. I followed those directions on the web site to the letter, except instead of using a light bulb for resistance I am using a 10 OHM, 10 watt resitor from Radio Shack. Now when I plug it in, I blow the curcuit breaker every time. I think this power supply might be bad, any ideas on where I can get a new one cheap, like for free?

Frustrated Airplane Nut.

scottm

you can get them cheap here:

http://www.outpost.com/template/computerspc/

Airplane nut

Wanted to report to everyone that I finally got this sucker to work....Yes..

The article it the AMA magazine was worthless for me, the article posted here from the web site was extremely helpful. I found the trick is that orange power good wire. I have an older ATX switchable power supply with un umbilical on/off switch. Once I hooked up the +5 volt red wire to the power good..Bingo! I am getting 11.6 volts, enough to run my Triton.

Thanks for all your input.

Now I bought a brand new power supply for $20.00 that I didn't really need, so if anyone is intersted....

jimbosstuff1

Just a little help here, what you means orange power good wire? You hook up the 5v red to the power good, whhaatt, I think I'm being a rock....whats the power good??wire???I hope I am not the only one that doesn't get it...dang...E-Jim

LoveToFly-RCU

My friend, go to "www.newegg.com" and you will find ATX (the best to convert) power supply for about $19- I got 5 of them to convert for my friends in the club> Don't use the resistor... it get very HOT instead I used an automobile stop light bulb the one with 2 filaments. I connected togheter the 2 central contact and then the outside for ground. All the power supply that i modified they give me 12.4 Volts at about 4Amp. with no problem. I put the bulb inside the case hold it some how and also serve as a power ON monitor. GOOD LUCK. ALDO

Airplane nut

Don't worry, it took me a while before I could figure it out too. The power good wire is usually orange, it was on my power supply. It will be comming off the main board. You need to take one of the +5 volt red wires and hook it up to this orange power/good wire. Don't ask me what power good means, I have no idea, but your power supply will not work if you don't make this connection.

You also need to put some sort of resistor across the +5v and one common ground, or black wire. I used a 10 Ohm, 10 Watt sand bar resistor from Radio Shack.

Good luck

Tetley

Ok take a pic of the sticker on top of the power sup, with color's and volts on and i will send u a wire diagram for it , or just post here the colors and volts of each one. (ther maybe 1 wire present thats not on sticker, just color will do)
The Power good wire is one half of the packs on switch and needs to be hooked up to the +5v vsb wire, bingo packs now turned on! ,then create a draw or an earth on one of the 5v lines then and only then will the pack give you 12v..
It can be a real head scratcher!!!, my ripmax Pro-Peak-profigy runs peachys of an old pc supply and the fan cools the packs as they charge.

Took me 20 mins to work out what the hell was going on!, but once u have it running u will see and say 'doh' oh yea [&:]

Jim

redxfred

My Feedback: (3)

[sm=confused.gif]Here's a link that lets you up the Amperage by using multiple power supplies. It's pretty cerebral, but it answers a few questions:...
http://www.antennex.com/preview/archive3/powers.htm