PSU modding to make it 12 V only

[D_o_S]

Hiya guys,

I need some help. I want to convert a PC PSU so that it is 12 V only. Well, actually, I'd like 13.8V, but the PSU has no pots, and I don't know how to do it otherwise... well, here's what I need:

PSU:
12(13.8V) output
Very clean and stable output (I heard you can put a cap somewhere, I don't know where)

I need this to power a charger that operates at 10-16V and I will charge batteries (6 cell packs, 7.2V) at 7A with it...

Any input appreciated.

P.S.: I thought I'd follow this: http://www.one18th.com/ShowArticle79.htm ... is it good?

[D_o_S]

Or could anyone post the part of a mobo that is used to "clean" current (schematic would be nice), or could someone design it...?

[D_o_S]

Anyone?

[punisher69]

Just use the Yellow(+12) and Black(-) of the end of a connector... power should be clean enough as it is. Regulation shouldnt deviate more then +- 5% which should be fine.

What is the make/model of psu?
How Many Watts?
How Many Amps is the 12v line rated at?

[D_o_S]

Well, I guess I'm not going to mod it... I got a calibrated Tektronix scope and I measured the ripple on the 12V rail and it was TERRIBLE! 0.7 V of ripple under 0.5A load :sick: It's an Eurocase PSU and cost about 50 USD... of course, I don't use it in any of my systems, that would be :shock: I just have it for playing around... I tried putting a capacitor in, it helped a little but not enough... I'm going to get a new PSU just for the job, it's not worth modding it

[STEvil]

thats probably because you had no load on the +5v rail and/or not enough on the +12v rail.

Try putting a couple HDD's on it.

[D_o_S]

thats probably because you had no load on the +5v rail and/or not enough on the +12v rail.

Try putting a couple HDD's on it.
I'll try that... and after I finished testing that PSU, I went on and tested my Enermax... it was much better, but it had 0.1V spikes on +12V... is this normal? I was testing it under load with the components in my sig

[STEvil]

for an enermax, probably.

[Revv23]

definetly put more load on it, some psu's are all over the place with no load...

i know thats how my FSP 530 was, if i jumped it with nothing on it the 12v could be anywhere between 12-13v, but put a few hdd's on her and it was 12.36 -12.38v alll day long.

[WeStSiDePLaYa]

i also need to do the same, but for just my pumps and rad fans.

[Calderbrae]

You could prob your own for close to that cost. Granted, you use some plastic, or cheap metal, project enclosure from Radio Shack.

The importance of clean power comes from good bridge diodes, converts the cosine wave input into all postive steps, and high quality capacitors, resistors, and voltage regulators.

Thats a pretty nasty ripple you talked about, but STEvil is right, should see far less when under more load. Try a few things with motors (hard drives) and something with non-resistive load (fans).