USB power only on a......

[Phrik]

USB power only on a slot bracket, 4-6 ports ?

Any of you know of a PCI(e) card or non(card) or adapter or anything where I can passthrough USB power only ?

I just basically want to power up 2 RPi1 and a 4-port network switch wich only requires 5V 1A, directly with the server's PSU. None of the devices needs USB connectivity to the server. I just want them to turn on when my server is also on. And I can just hot-plug it on/off the fly.

Any ideas, thoughts ? Thanks !

 

[michalrz]

I know you said USB, but how about using the 'red' wire from a molex connector? Red is 5V, Yellow is 12V, and two grounds in between.

From what I recall, molex connectors are 'hot pluggable'

 

[GotNoRice]

What type of adapter are you looking for exactly? Why not just take any old USB cable, cut the end off, single out the two wires you need, and use them?

 

[Nenu]

The port has to accept approx 1A, not all USB can do this.
USB 3.0 supposedly supports up to 900mA which should be ok.
More recent ports support even more, havent got time to look it up atm.

There are also hybrid ports that support more current.
These are available at the whim of the mobo mfr so mobo specs will need to be checked.

 

[Phrik]

I know you said USB, but how about using the 'red' wire from a molex connector? Red is 5V, Yellow is 12V, and two grounds in between.

From what I recall, molex connectors are 'hot pluggable'

Adding a molex plug on the other end of a USB isn't the problem, I can easily solder. But I'm worried if it is really hot pluggable. I still don't hot-plug anything that's directly connected to the PSU, not even HDDs. Last time I hot-swapped/plugged an HDD I blew up the PSU and the backplane enclosures.

What type of adapter are you looking for exactly? Why not just take any old USB cable, cut the end off, single out the two wires you need, and use them?

That's what I'm thinking, I have one of these http://www.amazon.com/MainBoard-Mot..._UL160_SR160,160_&refRID=0S5Y4WTEN03FKVRSE4Q3 and hookup a molex end for the 5V and ground. But I don't know anything about the amperage this would provide, I don't want to blow up another PSU or anything else. I connect cables, but I don't know anything about electricals

The port has to accept approx 1A, not all USB can do this.
USB 3.0 supposedly supports up to 900mA which should be ok.
More recent ports support even more, havent got time to look it up atm.

There are also hybrid ports that support more current.
These are available at the whim of the mobo mfr so mobo specs will need to be checked.

Yup, hence me looking for something where I could just plug a molex power source and the card or whatever distributes amperage accordingly to each port.

 

[CaptNumbNutz]

Adding a molex plug on the other end of a USB isn't the problem, I can easily solder. But I'm worried if it is really hot pluggable. I still don't hot-plug anything that's directly connected to the PSU, not even HDDs. Last time I hot-swapped/plugged an HDD I blew up the PSU and the backplane enclosures.



That's what I'm thinking, I have one of these http://www.amazon.com/MainBoard-Mot..._UL160_SR160,160_&refRID=0S5Y4WTEN03FKVRSE4Q3 and hookup a molex end for the 5V and ground. But I don't know anything about the amperage this would provide, I don't want to blow up another PSU or anything else. I connect cables, but I don't know anything about electricals

The power supply will supply as many Amps that the device is demanding, up to the limits of the PSU itself and the physical properties of the connector. If the PSU can provide 20 amps on the 5v rail, its not going to force all 20 of those amps down that little USB plug and blow up what's on the other end. In other words, you aren't going to pump out an entire river by using a garden hose. Any "hotswapping" issues you had in the past were due to problems with the device or enclosure the device was in. AFAIK, the plug itself can easily handle several amps of power even if the USB spec does not allow it. If it wasn't possible you wouldn't see USB chargers with USB 2.0 style plugs supplying 2+ amps to charge power hungry touch screen tablets.

Whatever you do, snip the data lines going to the USB plug (labeled D+ and D- in diagram below). Wiring an old molex plug 5v line (red wire) to a USB plug (red wire labeled VCC), then connecting ground (black wire) to USB ground (black, labeled GND) should work fine. Get rid of the 12v wire (yellow) on the molex. I would also label the plug itself with sharpie/tape or something so you know that plug only supplies power.

 

[michalrz]

I don't want to sound like I'm 'encouraging' you towards that particular path, but it honestly has less points of failure.
I have made mistakes in my life, like touching the 'black' wire - ground (0V) - to the case - it just shutdown. Same when I did some other genius move I can't recall. My friend uses crappy/faulty PSUs for electrolysis cleaning of old stuff he found via metal detector. Worst he's gone was that the insulation kind of didn't want to stick to the copper anymore. But it was rock solid fans blazing.
Make sure you connect 'ground' first, then the voltage.
If you want to play it safe, practice on some disposable PSU you may have laying around.

 

[CaptNumbNutz]

The port has to accept approx 1A, not all USB can do this.
USB 3.0 supposedly supports up to 900mA which should be ok.
More recent ports support even more, havent got time to look it up atm.

There are also hybrid ports that support more current.
These are available at the whim of the mobo mfr so mobo specs will need to be checked.

This information only applies to ports that supply data.

OP wants a power only port akin to the USB wall charger for a smartphone/tablet. If that's the case he only needs to wire something up himself using only 2 of the 4 wires in the USB plug. There are only a few instances where the data lines are actually needed for charging, but those are device specific. OP just want's 5v, 1A which is very easy to accomplish. I would recommend he just use a USB cell phone charger, but OP specifically requested it turn on/off when the computer turns on/off.

USB power only on a slot bracket, 4-6 ports ... None of the devices needs USB connectivity to the server. I just want them to turn on when my server is also on. And I can just hot-plug it on/off the fly.

 

[Nenu]

Yes, its very simple to find a 5V 1A power source, that isnt the issue.

The reason why USB was suggested is so it powers on with the PC.
You even covered the point, using it to debunk my post for some reason when that is exactly what I was covering as well !?!
Its a simple solution if the port can supply enough power.
Whether data flows is irrelevant, those wires are not needed but the ports max power output must be considered.

 

[MrGreg62]

Do you have unused USB headers on the motherboard? I remember things like these used to be included with some motherboards or can be purchased separately. Snip the data lines and you're good to go.

 

[Nenu]

Do you have unused USB headers on the motherboard? I remember things like these used to be included with some motherboards or can be purchased separately. Snip the data lines and you're good to go.

While they all supply 5V, anything older than USB 3.0 cannot supply more than 100mA unless its a hybrid.
He needs approx 1000mA.
USB 2.0 standard spec is the following:

https://en.wikipedia.org/wiki/USB

USB 2.0
...
Battery Charging Specification 1.1: Released in March 2007 and updated on 15 April 2009.
Adds support for dedicated chargers (power supplies with USB connectors), host chargers (USB hosts that can act as chargers) and the No Dead Battery provision, which allows devices to temporarily draw 100 mA current after they have been attached.

 

[Tsumi]

Adding a molex plug on the other end of a USB isn't the problem, I can easily solder. But I'm worried if it is really hot pluggable. I still don't hot-plug anything that's directly connected to the PSU, not even HDDs. Last time I hot-swapped/plugged an HDD I blew up the PSU and the backplane enclosures.



That's what I'm thinking, I have one of these http://www.amazon.com/MainBoard-Mot..._UL160_SR160,160_&refRID=0S5Y4WTEN03FKVRSE4Q3 and hookup a molex end for the 5V and ground. But I don't know anything about the amperage this would provide, I don't want to blow up another PSU or anything else. I connect cables, but I don't know anything about electricals



Yup, hence me looking for something where I could just plug a molex power source and the card or whatever distributes amperage accordingly to each port.

If you take that USB connector, connect one end directly to the molex plug, and the other to the devices you want powered, electrically speaking, there is no difference between doing that and connecting directly to the molex plug. Having it as a USB connector does not magically make it any different, to make a difference, it would have to go through a power distribution board or some other form of circuitry (like a motherboard). Otherwise, wires and connections are just wires and connections. No difference other than physical shape.

 

[Phrik]

Much appreciated on the information, I'll give it a shot, gonna start soldering and crimping the next few days for that USB PCI plug thingy. For now, I'll plug it with a spare PSU for testing.

Cheers very much !