Hi
I've been experimenting with dual PSU's a little bit. So far my limited tests seem to show that there does not seem to be a problem with simply cutting off all the connectors and soldering all the wires back together in order so that the 2PSU's are in parallel with each other. Apparently proper dual PSU's use load balancing or whatever but is this really necessary?

I want the 2PSU's for redundancy not because I need more power.

Another thing I have been looking into is a DIY UPS. Wouldn't it be much better to take out the 2main capacitors in the PSU and solder in wires to a battery as well as soldering the caps back in obviously.

Thnx Rufe0

 

I'm not as expert as the other members of the page, but I have blown up enough PSU's to tell you something:

I never heard about good results with parallel PSU. If you want more power, get a better PSU. If you want redundancy, you can get special PSU's with two AC jacks. If one AC source fails, the other is used inmediately.

I've heard about DIY modified PSU's used for car computers, giving from 12V the 12, 5, 3, 0, -5 and -12 used by the computer, but I don't really get how do they make the trick, I guess they remove the rectifiers, frecuency and step down circuit, and do some kind of black magic...

You can also buy the commercial version

Believe me, DIY is perfect for most cases, but on this application the smell of burnt oil is not good, the voltages of the game are dangerous, and I guess your equipment is too expensive to risk it

is your choice!

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La Rotta

 

never ever connect two PSUs in paralel, I had the need for more power and got a second psu to power my disks, so I unpluuge the HDDs from the main PSU and simply plugged the second psu into the HDDS, ok so far so good but 6 months down the line I opened the pc up again and found the power connector to the motherboard to be a bit burnt although the computer was still working fine, I can only assume that the 5 volts was going in paralel by means of the ATA cable signals, I was lucky, don't you try yours ! a slight difference in voltage between the two psu's will cause a short circuit since even mV across milli ohms is quite a shorting current

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I AM the exeption that disproves the rule in many ways but the rules still apply (unfortunately)

my site:www.simons-photography.com
http://rushdenrotaract.org.uk

 

there are two general ways to place dc sources in parallel - one is with a diode on each output (cathodes tied together) and the other is through a resistor on each output. The diodes will force a pn junction error in the output level and will also be lossy (unless you use a schottky - still lossy, but less lossy). the resistors will force the output to "droop" as load is increased. Both methods allow for the two DC sources to be "separated". The diode approach will insure that there is no sinking of current on one of the input rails. The resistor approach cannot guarantee this - especially at no or low load. I would suggest using diodes as the resistor approach can get hairy sometimes. the advantage to the resistor approach is that the current sharing between the two sources can be scaled by the resistor values.