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Does anyone know how I can bump up the 12V on a PSU to 13.8V for my 18W Laing DDC water pump with out having to resort to an external transformer? Something I could run off a 4-pin in the PSU. The reason for this is that I can gain a 1/2 gal per minute on flow and about 3 ft more head with the over volt. Thanks in advance.....
 

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If you somehow could join the 12v and 5v line, do that and put a resistor on the 5v.
 
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Discussion Starter #3
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<div>Originally Posted by <strong>gonX</strong></div>
<div style="font-style:italic;">If you somehow could join the 12v and 5v line, do that and put a resistor on the 5v.</div>
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Good idea, I would just need to figure out what size resister to lower the voltage to 13.8V Thanks..Anyone else?
 

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Get an adjustable resistor.<br>
Keep adjusting it down untill you find the correct voltage. Use a voltmeter to help.
 
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<div>Originally Posted by <strong>gonX</strong></div>
<div style="font-style:italic;">Get an adjustable resistor.<br>
Keep adjusting it down untill you find the correct voltage. Use a voltmeter to help.</div>
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Thanks, Do you think it might cause feedback on one of the lines or would the resistor stop it?
 

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I think a diode could prevent this. Obviously before the resistor.
 

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Combining a 12V and a 5V line wont increase voltage. In fact it will decrease voltage because the 12V rail will bleed off into 5V the rail and possibly damage anything connected to the 5V rail, including the PSU. The only way to overvolt it past 12V would be to connect it to the -5V or -12V rail, which would give you either 17V or 24V. However, most new PSUs dont even have a -5V anymore since that was used for ISA slots, and in most cases the -5V/-12V rail carries less than one amp, so it would not be sufficient to power an 18W pump.
 
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I sure do hope this PSU is dedicated to water cooling only! I would not do this experiment with a PSU that powers the rest of your rig...
 
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Discussion Starter #9
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<div>Originally Posted by <strong>HrnyGoat</strong></div>
<div style="font-style:italic;">Combining a 12V and a 5V line wont increase voltage. In fact it will decrease voltage because the 12V rail will bleed off into 5V the rail and possibly damage anything connected to the 5V rail, including the PSU. The only way to overvolt it past 12V would be to connect it to the -5V or -12V rail, which would give you either 17V or 24V. However, most new PSUs dont even have a -5V anymore since that was used for ISA slots, and in most cases the -5V/-12V rail carries less than one amp, so it would not be sufficient to power an 18W pump.</div>
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That was my concern with the feed back. I was thinking along the lines of some sort of capaciters. Thanks...
 

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Discussion Starter #10
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<div>Originally Posted by <strong>Chozart</strong></div>
<div style="font-style:italic;">I sure do hope this PSU is dedicated to water cooling only! I would not do this experiment with a PSU that powers the rest of your rig...</div>
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It will be. I'll be using the Ultra x-connect 2 in my sig ..Thats all it's good for, if even that...<img alt="" class="inlineimg" src="/images/smilies/wink.gif" style="border:0px solid;" title="Wink"> EDIT: I want to thank every one for there help! I have been looking around some more and think I will be going with something like this, have to research more to get the exact one I want.....Thanks again.........<a href="http://www.powerstream.com/18volt-index.htm" target="_blank">18 volt power supply and battery index</a>
 

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<div>Originally Posted by <strong>ira-k</strong></div>
<div style="font-style:italic;">That was my concern with the feed back. I was thinking along the lines of some sort of capaciters. Thanks...</div>
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<br>
the caps shouldn't do much on this since it is a DC cuicut. unless you are looking to smooth out the ripple a little more but that isn't goign to help in this case.<br><br>
best thing I can think of doing is grabbing a dedicated supply for this or as someone else said use the one of the -v lines but then you would need to more current then the ps will prolly supply.<br>
the only other thing I can think of is to use a DC-DC converter or convert to ac then multiply the voltage through a voltage doubler then use a a voltage divider.<br><br>
either way is not going to be cheap/easy I would say<br><br>
EDIT: ok so Im' late :) I tried at least
 

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Discussion Starter #12
Thanks, That's what I decided to do get a DC-DC converter..<img alt="" class="inlineimg" src="/images/smilies/smile.gif" style="border:0px solid;" title="Smile">
 

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well wish you the best but if nothing else I have one other solution that might work<br>
I can always take taht water cooling system and figure out how to make it work.<br><br>
just don't ask for it back I'll be tinkering with it for a LONG time <img alt="" class="inlineimg" src="/images/smilies/tongue.gif" style="border:0px solid;" title="Stick Out Tongue">
 

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Discussion Starter #14
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<div>Originally Posted by <strong>rx7speed</strong></div>
<div style="font-style:italic;">well wish you the best but if nothing else I have one other solution that might work<br>
I can always take taht water cooling system and figure out how to make it work.<br><br>
just don't ask for it back I'll be tinkering with it for a LONG time <img alt="" class="inlineimg" src="/images/smilies/tongue.gif" style="border:0px solid;" title="Stick Out Tongue"></div>
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...<img alt="" class="inlineimg" src="/images/smilies/biggrin.gif" style="border:0px solid;" title="Big Grin">...
 

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dont attemp to do this unless the powersupply is going to be used only for the pump be evan this will be dangerous the powersupply will have a much higer chance of failing or parts may go postal what you should do is make your own you could make one for about $15. thats what i would recomend.
 

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Well in technicalities, if u hook up 2 power sources in SERIES, it should increase the voltage. But since this is done on ONE psu, i wouldn't try it. Finding a 12v DC to 13.8v DC converter would be challenging and quite likely to be costly. U can convert the current to 12Vac and then use a transformer to stepup the voltage to 13.8v, but that will be highly impractical and complicated to do... This is a though one. I suggest you just by a seperate dedicated 13.8v PSU.
 

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<div style="margin:20px;margin-top:5px;">
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<div>Originally Posted by <strong>gonX</strong> <a href="showthread.php?s=fb118d83aa0ea05832d812d721028acf&p=1345623#post1345623"><img alt="View Post" class="inlineimg" src="http://static.overclock.net//img/forum/go_quote.gif" style="border:0px solid;"></a></div>
<div style="font-style:italic;">I think a diode could prevent this. Obviously before the resistor.</div>
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omg you know nothing! first off it doesn't matter where a resistor is in a cuircut. second an "adjustable resistor" is called a potentiometer or POT. third of all combining the 5v and 12v rail will do NOTHING you would have to convert it to ac, up the voltage, then convert it to dc again. not worth it for 1.8v anything that works on 13.8vdc should be fine on 12v<br><br>
edit:actually the best way would be to open up the psu and hijack the dc output before the VR and then get a combination of a VR and a resistor to bump it up. no telling what this will do to your system but it shouldn't have many if any ill effects
 

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Instead of a 2nd PSU, what about a toy train transformer? I can't seem to find any valid specs for output, but just a thought...
 

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<div style="margin:20px;margin-top:5px;">
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<div>Originally Posted by <strong>dralb</strong> <a href="showthread.php?s=fb118d83aa0ea05832d812d721028acf&p=3084137#post3084137"><img alt="View Post" class="inlineimg" src="http://static.overclock.net//img/forum/go_quote.gif" style="border:0px solid;"></a></div>
<div style="font-style:italic;">Instead of a 2nd PSU, what about a toy train transformer? I can't seem to find any valid specs for output, but just a thought...</div>
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Well thing is, a transformer only works with AC current, not DC. So u're gonna have to somehow convert the current back into AC and then use the transformer to step up, then rectify it back into DC. As i said b4, this ain't gonna be an easy task. If you're skilled and/or daring enough, you can try to build ure own 13.8v PSU...<br>
heres a link:<br><a href="http://sound.westhost.com/project77.htm" target="_blank">http://sound.westhost.com/project77.htm</a><br><br>
I'm gonna build meself one for my car audio setup later on <img alt="" class="inlineimg" src="/images/smilies/biggrin.gif" style="border:0px solid;" title="Big Grin">
 

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<div>Originally Posted by <strong>mashersmasher</strong> <a href="showthread.php?s=d51c1a11b1f7d586c94ba64097780a71&p=3084094#post3084094"><img alt="View Post" class="inlineimg" src="http://static.overclock.net//img/forum/go_quote.gif" style="border:0px solid;"></a></div>
<div style="font-style:italic;">omg you know nothing! first off it doesn't matter where a resistor is in a cuircut. second an "adjustable resistor" is called a potentiometer or POT. third of all combining the 5v and 12v rail will do NOTHING you would have to convert it to ac, up the voltage, then convert it to dc again. not worth it for 1.8v anything that works on 13.8vdc should be fine on 12v<br><br>
edit:actually the best way would be to open up the psu and hijack the dc output before the VR and then get a combination of a VR and a resistor to bump it up. no telling what this will do to your system but it shouldn't have many if any ill effects</div>
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....what are you talking about?<br><br>
1) A resistor reduces current draw to help prevent the motor from frying.<br>
2) For the load, a rheostat might be more suited. However there is nothing wrong with saying an adjustable resistor.<br>
3) Combining the +5v and +12v yields +7v.<br><br>
A step up transformer can be used.
 
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