12v USB Hub - $29.99 :-)

**hailrazer** · 09-07-2009, 07:03 PM

Originally Posted by PaulF

Because the power supply is 2 amps at 12 volts and each port is 500ma at 5 volts.

12 volts x 2 amps = 24 watts;
24 watts / 7 ports = 3.43 watts per port
3.43 watts / 5 volts = .686 amps
.686 amps = 686 mA

I'm sure whatever electronics that are in the hub use some power for themselves and efficiency is never 100% so the actually number is probably closer to 500 mA than to 686 mA, but it definitely is possible that each port gets 500 mA.

Ahhh thank you.

**PaulF** · 09-07-2009, 07:04 PM

Originally Posted by hailrazer

Ahhh thank you.

No problem.

**hailrazer** · 09-07-2009, 07:07 PM

Originally Posted by PaulF

Oh and also... heres my 2 cents on the hub...
If it is taking in 12 volts and outputting 5 volts, it has some sort of regulator inside of it. I bet that regulator accepts a range of volts and not just exactly 12 volts. The only way to know is to test it with a multimeter though.

That makes sense. A lot of Lcd screens that I use in making portables say 12v or 9v but they can accept anywhere from 7.4v-14v usually.

**summer69guy** · 09-07-2009, 07:15 PM

Originally Posted by hailrazer

How can each of the 7 ports be guaranteed 500ma with only a 2A power supply?

lol..magic electricity?

**afterdigital** · 09-18-2009, 06:43 AM

@kapone

did you get the unit yet?

**kapone** · 09-18-2009, 10:17 AM

Originally Posted by afterdigital

@kapone

did you get the unit yet?

Actually they had a delay in shipping and offered me a chance to cancel the order, and I did. Reading the specs again (more carefully) it does indeed require regulated 12v.

**afterdigital** · 09-18-2009, 12:52 PM

cool

thanks

**hailrazer** · 09-18-2009, 01:25 PM

I have one but I haven't had a chance to install it yet.

I am going to install it using the power regulator from my liliput screen if it can handle the amps.

My liliput screen is running off the 12v regulated output from my Carnetix 1900. But the Carnetix 12v output can't run this hub because it is only rated for 1.3A.

Will let you know how it goes.

**trader007** · 09-18-2009, 01:32 PM

Originally Posted by hailrazer

I have one but I haven't had a chance to install it yet.

I am going to install it using the power regulator from my liliput screen if it can handle the amps.

My liliput screen is running off the 12v regulated output from my Carnetix 1900. But the Carnetix 12v output can't run this hub because it is only rated for 1.3A.

Will let you know how it goes.

ouch dont pull that off your monitor's power... take it from your DC regulated power supply...

**hailrazer** · 09-18-2009, 01:40 PM

Originally Posted by trader007

ouch dont pull that off your monitor's power... take it from your DC regulated power supply...

Umm did you even read my post?

The Liliput is running off the regulated 12v from my P1900 power supply so it doesn't need the power regulator that it originally came with.

And I can't power the USB hub off the regulated 12v line from the P1900 because it only provides 1.3a and the usb hub needs almost twice that.

So the power regulator that was on the liliput (which I am not even using now) will be hooked straight to the battery and will be used to supply the regulated 12v for the USB hub.