Rig: Powering multiple 12V barrels with a single ATX PSU

[nedbert9]

Hello, BTCtalk.

I'd like to know if anyone has any good solutions on powering multiple 12V *cough* devices with a single ATX PSU.

The device connection is barrel type.

I've been reviewing info on single source / single rail 12V PSU and ATX PSU in general to see if I can wire the devices by splitting a single rail.

I'm altogether confused about what is possible.

Thanks for the help.

[P_Shep]

It's what I'm about to do (when the cables arrive). It's as straight forward as you may think.

1. Buy a load of connectors.
2. Wire them to the PSU.

More details:
The yellow wires on the PSU are 12V. Black is ground. Anywhere you see these wires, is anywhere you can attach your connectors.
To save cutting the wires on the PSU itself, I bought an 8-pin supplemental CPU power extender, and I'll be cutting that up and soldering the connectors to it. The 8-pin CPU power connector as 4 12V lines which can supply 8A each, which is nice and meaty for my purposes. You can also get the standard 4-pin molex peripheral connector too and use that, or use the PCI-E connector... all have the yellow 12V wires.

Only thing you need do after that, is short the green wire on the 20/24-pin Motherboard connector to any black one to turn the PSU on.

[nedbert9]

It's what I'm about to do (when the cables arrive). It's as straight forward as you may think.

1. Buy a load of connectors.
2. Wire them to the PSU.

More details:
The yellow wires on the PSU are 12V. Black is ground. Anywhere you see these wires, is anywhere you can attach your connectors.
To save cutting the wires on the PSU itself, I bought an 8-pin supplemental CPU power extender, and I'll be cutting that up and soldering the connectors to it. The 8-pin CPU power connector as 4 12V lines which can supply 8A each, which is nice and meaty for my purposes. You can also get the standard 4-pin molex peripheral connector too and use that, or use the PCI-E connector... all have the yellow 12V wires.

Only thing you need do after that, is short the green wire on the 20/24-pin Motherboard connector to any black one to turn the PSU on.

Great, thanks a bunch.  I feel better already about going ahead.

However, I'm wondering if I can safely get 1000W through 12V out of ATX PSU.  It seems that, where multiple 12V rails exist, each rail has a max 20A per ATX standard.
Though, there are 12V single source / single rail ATX PSU's.  I can only assume that this single rail has a high Amp rating.

Either way, I'm curious if there's an ATX that supplies high W, 600-1000W, on 12V.

[jake262144]

However, I'm wondering if I can safely get 1000W through 12V out of ATX PSU.  It seems that, where multiple 12V rails exist, each rail has a max 20A per ATX standard.
Though, there are 12V single source / single rail ATX PSU's.  I can only assume that this single rail has a high Amp rating.

Ummm... the 20A per rail limit was lifted with the latest (ATX12V v2.3) version of ATX spec, way back in 2007.

Either way, I'm curious if there's an ATX that supplies high W, 600-1000W, on 12V.

Almost any contemporary PSU design will allow you to draw almost all rated power off 12V rail(s), e.g. the XFX Core Edition Pro 850W allows up to 840W.

The design feature you should look for is known as DC-to-DC conversion: almost 100% of the PSU's rated power (excluding 5V standby and -12V rails) is being converted to +12V internally. 5V and 3.3V rails are converted from that so as long as you don't load those rails you're free to use as much 12V juice as the PSU is capable of.

[P_Shep]

Yep, your PSU documentation will tell you exactly how much juice you can take off each line. Some PSUs have multiple rails, some are single rails... it'll all be stated in the doc.

Just don't overload individual wires.

This is a fantastic resource for PC power connectors and their rating:
http://www.playtool.com/pages/psuconnectors/connectors.html

[P_Shep]

And info about rails:
http://www.playtool.com/pages/psurailhistory/rails.html

[jamesg]

I will pay 4 BTC (~$20) per connector and I'll buy 12 of them if someone makes these and ships them to me. So 48 BTC up for grabs.

If you think you can do this, PM me. If you think it will take more that 4 BTC per, PM me.

If you think you know someone who can do this, PM me.

[DeathAndTaxes]

I will pay 4 BTC (~$20) per connector and I'll buy 12 of them if someone makes these and ships them to me. So 48 BTC up for grabs.

If you think you can do this, PM me. If you think it will take more that 4 BTC per, PM me.

If you think you know someone who can do this, PM me.

What do you want the connectors to connect to?  

I would assume a 6pin PCIe connector adapter would be the most versatile.

1 PCIe 6pin connector to 1 12V barrels? or a multi-adapter (1 to 2, 3, 4)?
What is max wattage of the barrel connector?  (that will determine how many barrels can be powered by a single PCIe connector)
How long do you want the adapter to be 6", 12", 24"?
Do you want some heat shrink tubing to protect the entire assembly?
What is the specs of the barrel connector (polarity, ID, OD, length  or if you know a digikey part # would be even better)?

[jddebug]

I'm thinking I'll just cut the brick's power connector off and attach it to the 12v PCIe. It can always be reattached if need be.

Not sure how many can run off one PCIe connector though.

[nedbert9]

Thanks all for your help in clarifying and providing references

[P_Shep]

I'm thinking I'll just cut the brick's power connector off and attach it to the 12v PCIe. It can always be reattached if need be.

Not sure how many can run off one PCIe connector though.

3 off each PCI-E connector (as there are 3 12V lines).

[deepceleron]

I will pay 4 BTC (~$20) per connector and I'll buy 12 of them if someone makes these and ships them to me. So 48 BTC up for grabs.

If you think you can do this, PM me. If you think it will take more that 4 BTC per, PM me.

If you think you know someone who can do this, PM me.

It sounds like you want this:
4.20mm Pitch Mini-Fit® BMI Plug Housing + crimp terminals

to this:

2.5mmID x 5.5mmOD, +12V center

Just a guess...I'm thinking you need ~80+ watts (10A spec), which will require all six pins of the 75 watt PCIe power connector.

Note: Pins 1 & 3 of PCIe power are 12V @ 8A max physical; note that in the PCI-SIG spec, Pin 2 is not connected, and pin5 is ground-sensing (i.e. required but minimal current TO a ground). Probably most power supplies are dumb and wire like the colors show, but you need to follow the specs making a cable or you will find the exception.