USB charging direct from PSU

[Ghost416]

I've got an old 300w power supply that I want to use to power a few things. I can figure everything out myself except for one thing. I want to use the 5v wires for charging my phone using a USB cable.

 

I know that USB is rated at 500mA, but on the power supply it is stated +5v 30.0A on red wire and +5v 2.0A on purple wire. Usually I'd use the red wire for 5v devices, but since the Amp rating is so high can I use the purple wire instead?

 

I also thought a safer alternative is getting like a 12v USB charger that I can just connect to the yellow wire (+12v) so I don't have to worry about the Amp ratings.

 

Can anyone tell me if connecting the terminals directly to a USB cable would work or if I should rather go for the charger alternative?

[KingDaddyDaniel]

How many things are you planning on charging with the power supply? Do you own any device that measures your power draw from the wall? I would suggest comparing the results of charging everything you need off of the powersupply vs. using each device's respective charger

[Ghost416]

@Ghost416

It'll just draw what it needs (it isn't that complicated to understand -.-)

Plug in any +5V

 

That's what I thought, I just want to make sure so I don't blow anything. So I can just connect a USB cable directly to the red wire and it should work?

 

How many things are you planning on charging with the power supply? Do you own any device that measures your power draw from the wall? I would suggest comparing the results of charging everything you need off of the powersupply vs. using each device's respective charger

 

I'm mostly going to use it for about two devices. I don't have such a device to measure.

[Ghost416]

Yea, just double check polarity so yo don't blow your devices

also first chest with a multimeter the real values... IDK if +5V ATX tolerances are the same for USB

 

I just tried it and it works.

 

Thanks for the help.

 

 

For anyone who wants more info:

 

A normal phone charger gives a constant 5v, the power supply I'm using gives a constant 5.3v (which I guess is a standard). I did some research and the normal voltages for USB is between 4.75v and 5.25v, but up to 5.5v is acceptable.

 

My concern was mostly that the phone or whatever device needs a data connection to be able to charge. My Lumia 920 will charge without the data connection luckily, and it charges much faster than any charger I've used before.

 

---EDIT---

 

Just a quick update, this doesn't work for charging an IPhone (probably IPad and IPod as well) unfortunately. Apparently it needs the data connection to be able to charge, but everything else seems to work.