Thread: Cutting power to USB after computer has shutdown

As my machine starts to come together, this is a REAL important concern of mine.

I think im going to wait about a week to order my PSU, but as of right now im conerned with

A) do I go with a 90 watt PSU and hope its enuff

or

B) Hope that there is a decent work around to stop powering the USB hub/ mobo if I get a 150 watt PSU.

I realize that the 150W is meant to conform to Standard ATX specs...but when the #1 use for these are in automobiles, you think "we" could break the rules a little bit.

As im sure you have assumed from my user name I have a "lil" Suzuki Aerio...and I can not risk having uneeded power drained while im sleeping.

with how small the car is ...its just unacceptable.

Now if I had a Lincoln Navigator, then that would be a different story.

I subscripted to this thread and will be keeping an eye on it.

TIA to whoever gets this issue nailed down.

Originally Posted by 0l33l

Has anyone taken a volt meter to an Opus 90w? Maybe someone can email the manufacturer?

The 90W Opus can be configured to shut off completely via a jumper setting. The 150W Opus always supplies +5VSBY as long as the +12V input is energized.

Originally Posted by sagekoala

i could be suffering from simply being a newbie ... but it seems like he wanted to take the 5v from a molex connector to power a powered hub. in this case would the motherboard really be powering any of the devices on that hub. or when the opus shuts down doesn't ut turn off power to the molex connectors. (including the usb devices)

No, with this configuration, the +5VSB rail won't be powering any of your external peripherals since power to the 4 pin connectors is disabled when the PSU is off. The problem is that the motherboard itself will still be consuming power via the +5VSB rail.

Originally Posted by SuzukiAerio

I subscripted to this thread and will be keeping an eye on it. TIA to whoever gets this issue nailed down.

Follow the link in post #3 of this thread. The solution is already nailed down.

Originally Posted by aoLhaTer

problem is, i have no idea what this stuff means

Well, you're going to need to learn to read schematics if you plan to work with electronics. There is nothing complicated in that picture. It's just your computer, your PSU, a relay, three diodes, and some wire.

and you said yourself, even with this added mod, the opus psu failed to startup sometimes
doesnt seem like a great solution to me

No, I didn't. Reread the thread. The startup problem only happened when the relay was configured to switch the Opus 12V input. The diagram you posted is a solution that works without any problems. It will cut your power consumption to only a few milliamps when your computer is off.

Originally Posted by kreyzig

I used "double pole double throw mini relay"
http://www.radioshack.com/product.as...5Fid=275%2D249

and 1N4001 diodes
http://www.radioshack.com/product.as...Fid=276%2D1101

no need to use resistor.

Works great....

Yep, those should work just fine. Any 12V relay with a contact rating of 1A or more should be fine. Any 1n400x diode should work also.