Multiple power supplies. - page 2. | Bitcointalksearch.org

chungenhung

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Quote from: c_k on September 06, 2011, 05:52:09 AM

Quote from: chungenhung on September 05, 2011, 10:11:50 PM

Quote from: k9quaint on September 03, 2011, 04:06:03 PM

Get one of these so the power switch will turn on both power supplies.
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=34_186&products_id=21193

Then just split the PCIE plugs to the vid cards between the PSUs.

They are out of stock, so is FrozenCPU.com.
Anyone know where else to get them?

http://www.cablesaurus.com/ Cheesy

but the price is kind of high...

c_k

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Quote from: chungenhung on September 05, 2011, 10:11:50 PM

Quote from: k9quaint on September 03, 2011, 04:06:03 PM

Get one of these so the power switch will turn on both power supplies.
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=34_186&products_id=21193

Then just split the PCIE plugs to the vid cards between the PSUs.

They are out of stock, so is FrozenCPU.com.
Anyone know where else to get them?

http://www.cablesaurus.com/ Cheesy

BkkCoins

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firstbits:1MinerQ

Also just try that 2nd PSU on it's own with hard drives/loads. Or swap it with #1 and make sure that the PSU doesn't have some problem that no amount of tweaking will fix. Or try it in another system.

ajareselde

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Quote from: BkkCoins on September 06, 2011, 01:19:57 AM

Some PSU need load on 5V and some don't - according to what I've read. Apparently if the PSU is "group regulated" then it needs that load. I've also read that 100mA should be enough but haven't tested that myself. I don't know if 3.3V line is just as good but I suspect it is derived from 5V and would be the same.

V=IR, R=V/I R = 5 / .1 = 50 ohms

So if you have 75 ohms you may need two in parallel, = 37 ohms.

@ 37 ohms, I = V / R = 5 / 37 = 0.135 A
P=VI = 5 * 0.135 = 0.675 W across two resistors is 0.38 W each.
So you would want 1/2 W resistors for that.

If you only have 1/4 W resistors handy you should likely use a higher 100 ohm value or they may burn out after a while. Or put more in parallel or try on 3.3V line.

If you put 2 parallel 75 ohm on the 3.3V line you'd have 89mA - maybe enough.
And power dissipated in resistors would be 3.3 * .089 = 0.29W total or 0.145 W each.
Probably ok.

3 75 ohm inparallel on 3.3V line is 132 mA. And 0.436 W / 3 = 0.145 W each as well.
But this gives a bit more load.

ill try this after work.

+12v rails will be loaded with gpus.

+5v with hard drives

+3,3v with resistors

ill post how it went later.

BkkCoins

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firstbits:1MinerQ

Some PSU need load on 5V and some don't - according to what I've read. Apparently if the PSU is "group regulated" then it needs that load. I've also read that 100mA should be enough but haven't tested that myself. I don't know if 3.3V line is just as good but I suspect it is derived from 5V and would be the same.

V=IR, R=V/I R = 5 / .1 = 50 ohms

So if you have 75 ohms you may need two in parallel, = 37 ohms.

@ 37 ohms, I = V / R = 5 / 37 = 0.135 A
P=VI = 5 * 0.135 = 0.675 W across two resistors is 0.38 W each.
So you would want 1/2 W resistors for that.

If you only have 1/4 W resistors handy you should likely use a higher 100 ohm value or they may burn out after a while. Or put more in parallel or try on 3.3V line.

If you put 2 parallel 75 ohm on the 3.3V line you'd have 89mA - maybe enough.
And power dissipated in resistors would be 3.3 * .089 = 0.29W total or 0.145 W each.
Probably ok.

3 75 ohm inparallel on 3.3V line is 132 mA. And 0.436 W / 3 = 0.145 W each as well.
But this gives a bit more load.

Transisto

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I'm personally having a few built setup this way.

I just strip the two (green and a ground) twist them, then the PSU stay ON all the time,

I power the "stay on" before the other on the mobo.

work well. (so far)

ajareselde

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Update:

i finaly bought everything i need, but 2nd psu wont jump start without load.

i tryed hooking 2x 2.5 inch hdds, and some vents, but still nothing.

tryed also with 75 ohm resistors on 3.3v line and again nothing.... ideas ?

Transisto

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What about the need for pulling from 3-5v ?

Is it only needed on some PSU or ?

chungenhung

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Quote from: k9quaint on September 03, 2011, 04:06:03 PM

Get one of these so the power switch will turn on both power supplies.
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=34_186&products_id=21193

Then just split the PCIE plugs to the vid cards between the PSUs.

They are out of stock, so is FrozenCPU.com.
Anyone know where else to get them?

BkkCoins

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Activity: 784

Merit: 1009

firstbits:1MinerQ

Quote from: haploid23 on September 04, 2011, 07:44:42 PM

i'm also using dual PSU on one of my rigs. does it matter that they do not have a common ground?

As soon as you connect them to the cards they have a common ground anyway. I'm not sure if there's a valid reason to explicitly add a ground on the connector but it can't hurt either, and is the way people have been doing it.

m3sSh3aD

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I wouldnt think so, but that depends on where you are and many other factors. Im UK so solid 230-240V

haploid23

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i'm also using dual PSU on one of my rigs. does it matter that they do not have a common ground?

m3sSh3aD

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Quote from: ajareselde on September 03, 2011, 04:02:04 PM

Here is the deal;
i need to hook 2 power supplies to my rig.

how can i set it up to both start at the same time? is it safe to use 1 psu on mbo and 2 gpu-s, and 2nd one on other 2 gpus ?

would be nice if u could point me to some associated thread.

cheers

Green and black cable on the 24 pin, 3-4 along top row from left. Link them together and it comes on Wink

It works....

http://imageshack.us/photo/my-images/694/imag00032w.jpg/

BkkCoins

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firstbits:1MinerQ

A dual-adapter works but you can also hook it up yourself and get the same results if you can't wait for one to come in the mail.

On the ATX connector you join the green wires from each PSU and one black wire from each.

PSU1 PSU2
blk ---- blk (Ground)
grn ---- grn (PWR-ON)

When the power on (green) line on the first PSU gets pulled low it now also pulls low on the second - which causes both to turn on. There is only a very small signal current on this line.

To do this some people just push a wire into the pin slot to make contact. Ideally you would solder it but also pulling the pin and wrapping around it works. There is usually small "barbs" inside on the pin and they need to be pressed in to release a pin. I've also seen pics of people who used "splice" connectors but I'd personally prefer not to damage the wires on the PSUs.

k9quaint

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Get one of these so the power switch will turn on both power supplies.
http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=34_186&products_id=21193

Then just split the PCIE plugs to the vid cards between the PSUs.

ajareselde

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Activity: 1722

Merit: 1000

Satoshi is rolling in his grave. #bitcoin

Here is the deal;
i need to hook 2 power supplies to my rig.

how can i set it up to both start at the same time? is it safe to use 1 psu on mbo and 2 gpu-s, and 2nd one on other 2 gpus ?

would be nice if u could point me to some associated thread.

cheers

Topic: Multiple power supplies. - page 2. (Read 4786 times)