Introduction: More Power for Your Pc. (Second PSU \ Power Supply)

Picture of More Power for Your Pc. (Second PSU \ Power Supply)

This instructable will show you how to give you a bit of leeway if your videocard (or if you have only one 12V rail it'll be able to give more power to both the cpu and videocard). Just before we get started this is not the master and slave set up. That set up doesn't work for all pc's but this is guaranteed to work.

This is only recommended if you haven't got enough power to your system and you're running a few fans and hardrives cddvdroms

WARNING: read the comments for safety measures

You will NEED to link the ground connections in order to make this a lot safer. When I wrote this I was unaware of the voltage on data lines (Sata, IDE ect).

All you need is

A second powersupply (wattage dependant on what you are running but most likely even a 300 watt one will do.)

A paperclip or a small cable

And somewhere to place the second PSU (inside the case is recommended but not always advisable depending on the amount of room you have inside your case.)

You may also possibly need electrical tape (optional to cover the paperclip and prevent short circuits) and power extensions (IDE /SATA) if the cables are unable to reach to your devices.

A WARNING DO NOT plug in the 24pin or the 12pin creating a mix of power between the first and second PSUs is not a good idea as it may damage your motherboard.

Plugging only one PSU into the motherboard is appropriate.

Its advised that you only do so with the case PSU otherwise you may not have power to your hardrive (unless you plug that into the second one too) when you turn it on (not dangerous just useless).

Step 1: Jump Start.

Picture of Jump Start.

Step 1 Jump start

The first step is to put in a paperclipwire into the GREEN pin and into a BLACK pin (On the 24pin/20pinconnection). This can be different for different units. But the colours are always the same. This is the on signal (green) and ground so when power is going to the power supply and it is switched on at the unit it will jump start.

You may want to tape up the connection after doing this. Just to be safe and not cause any short circuits.

Step 2: Connecting Up Peripherals\fans.

Picture of Connecting Up Peripherals\fans.

Step 2 Connecting up peripherals\fans

Now you need to connect up all the hardrives\cdroms\fans etc.

This is where an extension would come in handy if you have it outside of the case.

Step 3: Turn It on and You're Done.

Picture of Turn It on and You're Done.

Step 3 Turn on the second PSU

Turn it on and tah dah. Your Videocard (and cpu if its a single 12V rail main PSU) will now have enough leeway to consume a lot more power (depending on how many peripherals were connected.).

Don't forget to turn it on before you turn on the computer though. (useless if you don't because you hardrive won't turn on.)

Enjoy all that extra power ;).

Comments

r00x (author)2010-12-22

Oh my... this is disastrously dangerous! You're powering different components from rails that could be at vastly dissimilar potential to each other. In short it looks like you got lucky, as you could've broken all your stuff or simply started a fire by trying this.

That ground/0v you get from a power supply is only at ground/0v relative to that particular PSU. Imagine if there was a 20V difference between ground on each supply!! Boom!

Jords001 (author)r00x2011-01-29

No actually, because the two power supplies don't meet at all. One is powering all the hardrives and fans etc and the other one is powering the main components. If I'm not mistaken A: fans have no connection at all to the main PSU when hooked up this way and B: Data cables carry no power cables inside them. Best option is get a good powersupply or build one to be honest though.

r00x (author)Jords0012011-01-29

While it's true the fans are electrically isolated from the rest of the system, the other components (i.e hard drives) do maintain an electrical connection to the motherboard via their data cables; this is how they transmit the data.

The data cables are subject to the same issues with potential difference. For a given device, the logical 1/0 signals it sends down the line will only be running at their rated voltages with respect to the ground the device is connected to.

That means what should be, for argument's sake 0-1.7V and 3.0-5V for logical 0 and 1 respectively could in fact be 10-11.7V and 13-15V at the other device. Meanwhile at the other end, we could be seeing voltages in the negatives for logical 1 and 0!

That means (assuming the PSUs have mismatched grounds) that at best you wouldn't have a working system, because as far as either device is concerned, their communication lines are locked high or low. At worst, it would damage your components and all sorts of interesting things could happen!

After firing both PSUs up without anything connected, I'd probably test with a multimeter across ground on both of them to see if there's a difference, and then make sure to connect their ground cables together for good measure. Make sure you don't try this on a computer you care about!

SepehrS5 (author)r00x2017-03-07

There is no need to check their voltage even about 500 volts would not do a thing....

Jords001 (author)r00x2011-01-29

Hmm, that's a very good point. I didn't know data cables carried those eep. Well I'm going to write read the comments for safety measures :) Thanks. I have a new PSU now so fortunately this is not a problem for me haha :). But it's very true, and I wouldn't want someone to fry their computer over something I've written.

SepehrS5 (author)r00x2017-03-07

No there is no danger in that it's not a hollywood movie to boom the just have a different potential after connecting them after less than 1 ns they would have a same ground the problem its not here at all the problem is that they may not be an exact 3.3 or 5 or 12 for an example they are 12.1 and 12 deepens on what chip u use it may one of them have a higher high voltage it would drain a constant flow which warm up ur circuits.

I can't see any other problem.

I have followed the steps but the second power supply didn't switch on! I decided to use a connectpsu adaptor instead and it worked.

therealgregwoo (author)2014-01-31

Here's a much better solution that doesn't involve paper clips and wire hacks: http://www.legitreviews.com/add2psu-daisy-chain-power-supply-adapter-review_1698. Someone actually made a little nifty device that makes this possible.

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