chadr

thanks, so i can't connect the white to white wire and the black to black without this special switch so its on whenever the power supply is plugged in?

Andrew

You can, but the power supply will power up when plugged in and continue running until it's unplugged from the wall. The switch simply adds some convenience.

russo11218

My Feedback: (-1)

Hello,I recently have run across this forum and have decided to give this mod at try .But I was woundering how easy would the conversion be to a newer atx power supply ? I have purchased this power supply from new egg either way i would like to try my luck on this one .

http://www.newegg.com/Product/Produc...82E16817148004

So,I guess may be if i could get some pointers or suggestions on what to look for on a new atx ps conversion would be awesome .I have all ready downloaded this http://www.wikihow.com/Convert-a-Com...b-Power-Supply
But it refrences older stlye atx ps does this make much diffrence ? like i said before any info would be a great help to me . thanks ahead of time bert

kinzuagolfer

That is a cool looking power supply. I used this guide as reference when I modded my power supply. It wasn't that old. Maybe 3 or 4 years old from a HP desktop. I bought a more powerful one a while ago for my vid card.

What I did was much more simple and unclean. read my post on the last page if you want details.

RichT

I'm just about to have a go at this mod with an old Antec 330W PS. This psu has 17A at 12v and 30A at 5v.

The charger I will be using has an input range of 10 - 18 v.

I am wondering if it will be possible / beneficial to rig up the -5v line as the negative and the +12v as the positive to get a net 17v output from the psu. Should I just stick with the healthy 17A 12v line or attempt this theoretical 17v line ?

All thoughts, comments and concerns are welcome.

Andrew

You will get 17 volts, but if you check the current rating of the -5v rail, it will likely be around 200 to 400 ma. - however, I suspect that it will not carry much of a load since the rail will overload very quickly. Stick with your 17A 12v line.

kinzuagolfer

For some reason this just doesn't sound right. It looks good on paper, but I don't think it works that way.
I'm no electrician, nor have I played with power supplies. Try it out see what ya get.

RichT

Thanks for the sage advice. I too had the feeling that it was beling a little to risky. On closer inspection of the ratings sticker I confirmed that the -5v had a 0.5A max current rating... so Andrew was absolutely right.


I went ahead with the snipping and soldering last night with great success. I have not (yet ?) put any load on the 5v line to boost the 12v and am getting 12.02v no load and 11.89v when charging. My charger range is specified as 10 - 18v so I'm confortably within spec. I will try adding load to the 5v line tonight if time permits to see if the effect is worthwhile... I can't see that getting 0.12v (1%) would have that much impact on the charger.

For anyone not sure if they can do this... have a go it was easy, worked well and was quite satisfying. Just two important points to obey: 1. DON"T PLAY AROUND INSIDE THE PSU WHEN PLUGGED IN and 2. MAKE SURE YOU DON'T LEAVE ANY EXPOSED WIRES THAT COULD SHORT.

zjwhitrock

and wait 1+ min. before opaning it after you unplug it!

chadr

I would like to use my power supply to directly charge a 3s pack of a123 batteries. I have packs of a123 that are directly charged using a car battery and simple voltage cutoff device. My 12v 8a max power supply has actually charged up a few packs then one day it blew a capacitor. I put in a new capacitor from radio shack and it works fine still. To keep the amp rate at 8a or less when charging from a car battery I used about 6 feet of 18 or 16 gauge speaker wire. When I connect the a123 packs to the power supply the initial load likely surges to more than the 8 amp power supply max rating though. Is there a way to limit the initial amp spike so it doesn't exceed the power supply rating? Is there something inexpensive that I could place inline to do this? I know I could get a charger that puts out up to 10amps but that will cost me some $$ too. My charger can only supply about 5 amps and it takes 25 minutes to charge the batteries. With the a123 packs connected directly to a car battery or my power supply it only takes 15 min, which is what I really want. Then I don't have a 10 min wait between my next run when using ac power to charge... and I don't need to use my car battery.

I am considering buying a 12v 20a capable power supply if there is no solution.

Snipin_Willy

I did my first conversion last Friday on a 400w generic power supply. Used only a 10w 10ohm sand bar resistor with heat sink compound against the inside of the case with the fan air moving over it. I can't even tell it gets warm. Best part of the build is that NOTHING BLEW UP! I was so stoked when I turned it on and didn't fry anything. Provided 12 amps at 11.84V, goo enough for me! Great mod and easy to do for the electrically inclined.

helijet3

Can someone help me with this? I'm trying to get my ATX psu to work with the led light toggle switch. However, I can only get either the fan to turn on or the led light. My goal is to have both the fan and light turned on at the same time. The switch has three posts: POWER, ACC, GROUND. I want to know to to connect the wires to the posts to get both the fan and light work. I would really appreciate if anyone can help me with this. Thanks.

thunder9000

i used a 200w that doesn't have a sense wire(brown)it had 2-12 pin connectors,anyway i get 11.4v soon as i start charging it goes down to 11.00 then the charger quits.but if i switch from 115 to 230 while its on(switch operated)it will charge a battery at 4amps plus charge my igniter.nothing seems to be overheating or sizzling.was wondering if i have to add a load to the 5v.?any help will be appreciated.seems i've answered my own question after reading Andrew's tutorial,i just put a load on the 5v presto! 12.12v.

StevieM

Many thanks for all the information here.
-
I have a query.
-
I am converting my 2nd supply (ATX)
-
10 ohm 25W W/W resistor, green switched via toggle to ground, grey via limiting resistor to ground.
-
-
The strange thing is this:-
-
Once it has latched on using the miniature toggle, I am unable to turn it off using the toggle.
-
The only way is to switch it off at the rocker switch adjacent to the mains inlet.
-
It is obviously not a problem...I just cannot understand why it's happening.
-
Any ideas???
-
Many Tks, Steve

Andrew

Cut the gray.

[link=http://web2.murraystate.edu/andy.batts/ps/POWER_OK.HTM]Here is an explanation[/link] of the purpose of the Power_OK rail.

StevieM

Andrew,

I had read the link you have posted above.
-
It suggested that a voltage on the proved the tha POST was entirely successful...I didn't realise that if this was grounded to any extent, it would inhibit the ability to power down by ungrounding the green.
-
I'll snip it and tie LED to a red with appropriate limiting resistor.
-
-
Just tested this tonight.
-
+12v side rated at 24A.
-
Loaded up to 21A using 2 X NiMH chargers, each serving a 10-cell 3300mAh pack (both at 6A......yes...these GWS chargers really do draw 10.5A when charging 6A!).
-
At this loading, voltage dropped from 12.65V to 11.95.
-
PSU seems very happy at this loading...don't wish to push it much further.
-
Many tks, Steve
-

chadr

I am converting my third power supply and this one isn't working yet. I've connected a couple 12v bulbs to the red and black wires for a load, which works well on my other power supply. This one has a small brown wire connected to the orange wire in the large connector. What darker colored wire do I connect the small brown wire to?

chadr

I should have mentioned that I connected the small brown wire to the orange wires but it didn't do anything different. Here are some pictures of the wiring and power supply -

[link=http://picasaweb.google.com/chadrebuck/Powersupply?authkey=dylxmqPfpME#]http://picasaweb.google.com/chadrebuck/Powersupply?authkey=dylxmqPfpME#[/link]

dmccormick001

chadr:

I notice that you haven't gotten any response yet from either of the experts lurking around here, so I'll take a shot at helping you. I've converted about 2 dozen supplies in the last few years. Even though you said this was your third conversion, they're all different, so I may suggest something you've already done.

1. Make sure the green wire is connected to one of the black wires, either directly or through a switch.

2. The brown wire may need to be connected back to the same orange wire it was with in the harness. Try ALL the orange wires.

3. Try removing the wires from the binding posts. It seems like a lot of guys are having trouble keeping the posts from touching the case, which causes a short that will make the PS shut down.

4. Be sure the PS really isn't working by checking for voltage across one of the rails, don't just assume it isn't working because the fan isn't turning. The fan could be bad.

5. Last but not least, try a different power cord.

Good luck!

David

TRXRUSTLER

My Feedback: (7)

how do I get my psu to put out more than 12v, Iwant more like 14v?

Red Scholefield

My Feedback: (9)

I don't think you can get there from here. Computer power supply designs are fairly tight. You would have to do some serious rework, rewind the toroid, etc.

erocki

My Feedback: (1)

I need some help. I read the Design Guide but something doesn't make sense. I have tested the power supply and it was above 12V, hooked up two 10w10ohm resisters to red/black, power seemed to be White/Black which is switched, and 4 Yellow and 4 Black for the 12V supply meant to be hooked up to my Ultra Duo Plus 30 charger.

I turn on the power supply, it powers up fine, reads fine, fan running, etc. Once I connect up the charger, the charger starts running though its startup. At the end of its startup, it kicks off the ppwer supply. If I turn off the power supply then back on, it will turn back on but then kick off again at the same point on the charger.

Since I am dealing with a Shutdown Unkown, I wanted to seek help. As you can see with the pictures, there is a vertical small board with a smaller guauge green wire and a regular sized purple wire.

What do I need to do to stop it from cutting off when the charger starts up?

dmccormick001

For starters, I'd remove one of the 10 ohm resistors. By connecting two in parallel, you've reduced the load they are placing to just 5 ohms. And it looks like you are grounding the gray wire through your switch, instead of the small green one. Try the green one and see what happens.

David

erocki

My Feedback: (1)

Thank you for your reply. The Green wire, heavier gauge, does nothing when it is connected up to a Black ground or switch. This wire has no effect.

Secondly, the wire color on the switch right now is 'White', not grey. When this is switched, it starts up the PSU but then fails when the load kicks in with the charger.

I am keeping the extra resistor on their to keep the heat down.

Anyone else...can someone help me with some suggestions?

*Also, I should mention that I have 3 PSU's...all three are 200W'ers with 6A MAX on 12v+. I have tried all of them, with loads and without, and they all shutoff that the same point. Once the Charger reaches its final boot up sequence, it must spike or something because all three PSU's power out at that moment. Once I recycle the power off/on, then it will start the same thing all over again.

Why does this happen and what are the fixes for this moment of spike? How can I get the PSU not to do this?

dmccormick001

Look for a smaller gauge green or gray wire. If you can see the PC board clearly, it usually terminates onto the board by itself, apart from any of the other wires, and sometimes you can see the letters "PG" printed on the PC board next to where the wire connects. The PG means power good, and you need to ground this wire to latch the PS "on".

OK, I couldn't tell from the picture. I don't know of any white wire in the PS that needs to be grounded. IIRC, most of the time the white wire is providing -5 volts (negative five volts, which is different from ground). If you are grounding it, the PS may be sensing this as a short and shutting down.

Well, that's fine, except you're cutting the load you are placing on the 5 volt rail in half, so your output may not be quite as good as you'd like, this is, it may fall a little shy of 12 volts, and you don't need the extra heat disipation. I've never had a 10 ohm 10 watt get more than slightly warm, especially mounted to the case near the fan.

Whatever you're doing wrong, you're doing it consistently. It may be the white wire/grounding switch thing, try not grounding that white wire. If the supply doesn't come on, look for the PG wire and ground it instead. There is no "fix for this moment of spike". If the PS senses no load, may not come on, once it does it checks for problems in the circuits and if it senses a problem, it will shut down. I think that's what's happening to yours.

David