topbuzzuk
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PC power supply conversion to 22amp 12volt psu?
I got given a 230watt PC internal power supply the other day. The guy had converted it and it runs 22amps at 12 volts, well its just under 12v 11.83v to be exact. Has anybody heard of these conversions? Ive looked inside and all i can se is that all the power wires have been binned apart from one set which go to the power poles he has fitted and its had a resistor of some kind added. It works a treat and probably cheap as chips to make, 22amp switch mode supply. 
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26FB118
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9/Oct/2011, 9:08 pm
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108FB360
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Registered: 11-2009
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Re: PC power supply conversion to 22amp 12volt psu?
Hi Paddy
Might not be that helpfull but check about 24 25 min into vid see if it helps
http://youtu.be/JpwDhMO0k5E
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Rab 108FB360
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10/Oct/2011, 12:34 am
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topbuzzuk
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Re: PC power supply conversion to 22amp 12volt psu?
cheers for that, it was a bit indepth for me building one from scratch  i have had a google and found a few things on them. i'm going to get a few parts at maplins and have a go at converting one i have here which is more powerfull than the one i was given. It seems a cheap way to get a 20+ amp switchmode power supply.
The 22amp psu i was given is 230watts, i wonder what ampage i would get from a 700watt PC psu?
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26FB118
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11/Oct/2011, 8:05 am
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yamanx1
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Registered: 09-2007
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Re: PC power supply conversion to 22amp 12volt psu?
w = v x a 
700w @ 230v = 3 amp draw
@12v 700w = 58.3 amps
However, the transformer from 230 to 12 wont be 100% efficient, say 90% efficient (Rough guess).
About 52 amps @12v
But really you'll need near 14v (13.8v)
So 700w @ 14v x 90% eff. = About 45amps
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By all means think yourself big, but never think others small.... R.F.Scott |
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11/Oct/2011, 8:49 am
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Hot Fusion
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Registered: 03-2008
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Re: PC power supply conversion to 22amp 12volt psu?
It is quite easy to convert a computer PSU to output 12 volts, which they are designed to do anyway. These PSUs output several different voltages, and one of the low voltage rails needs to see a continuous load or the PSU will not operate - it's a safety thing. That would explain the resistor.
The total wattage of the PSU takes into account all supply rails so you would need to look at the specs to see what the output current is for the +12v rail alone.
I'm not sure how easy it would be to increase the voltage to closer to 13.8 volts - the regulation may be on-chip, I'm not sure about that. If it is a resistor divider network then it would be easy to modify - I'll leave that to be answered by someone who has actually operated on one of these.
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Andy - FB107
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14/Oct/2011, 7:33 pm
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29fb380
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Re: PC power supply conversion to 22amp 12volt psu?
I have a 150watt psu in front of me it says +12v 4.6A and +5volt 18A so unless you want to hook three psu's in series for 5volt it wont give much amperage. I think.
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13/May/2012, 10:14 pm
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26fb530
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Registered: 02-2011
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Re: PC power supply conversion to 22amp 12volt psu?
i seen these conversions for sale on ebay clamming for amateur radio use
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73's
Tony
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14/Jun/2012, 7:01 pm
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CraigOWL
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Registered: 06-2010
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Re: PC power supply conversion to 22amp 12volt psu?
I was asking around to get my old pc to run a radio at home,and was given this link.
Sounds very much like the ones described above to be honest.
http://elektronikbasteln.pl7.de/converting-computer-power-supplies-to-stabilized-138-v-dc-20-a.html
Craig.
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26FB79 26FI79 26SY351 26OK64
"Women are like old Lambrettas,you can only push them so far"
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29/Sep/2012, 6:05 pm
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CraigOWL
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Re: PC power supply conversion to 22amp 12volt psu?
This is in better detail,with better pictures,and looks like a good project,well worth the effort.
The fact that it comes from U.S.A doesnt matter,just convert doller to quids.lol
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply
Craig.
Last edited by CraigOWL, 29/Sep/2012, 7:11 pm
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26FB79 26FI79 26SY351 26OK64
"Women are like old Lambrettas,you can only push them so far"
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29/Sep/2012, 7:10 pm
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