disable power to a usb hub?

**dragons0088** · 05-06-2009, 04:32 PM

Hey guys, I've got my carputer running off an MSI wind book. When I put it into sleep mode it barely even lasts for an hour. I figure this is because the USB hub that i have all my usb devices (bluetooth, gps, soundcard) plugged into is drawing power from the laptop and not the external power cable plugged into it. I found this out by unplugging my the power from the hub and the devices still worked 100% fine. Also I put the laptop to sleep with no usb devices plugged in and it lasted 24+ hours. My work laptop can goes 3+ days in sleep mode with no problem.

So, that being said, is there any way to tell windows not to allow power to go to the specific usb port? So that they HUB is forced to power my devices and when power to the HUB dies so do the devices plugged into it. Also how can i tell which port in the device manager is my USB hub. The only usb port that i want to have power going to in sleep mode is the touch screen so that i can wake it up when i power the car on (I found out how to get this working).

**Flaring_Afro** · 05-07-2009, 04:43 PM

well, first off unless very far lengths, any hub will work with no power cable so them working with hub unplugged does not prove that they are drawing power while its in sleep mode. the time difference does though. you can turn off usb ports by going to device manager and clicking properties over a port and going to power management tab and checking the box next to "allow computer to turn off device to save power". however, you can only do this for ports on laptop, meaning you cant do something specific with 1 port on a hub and leave the rest off. you will have to plug your touchscreen into one of your laptop ports.

**dragons0088** · 05-11-2009, 12:25 AM

Hmm I tried going into the properties of each of the usb devices and there wasnt a power management tab on any of them. Just on the "USB Composite Devices" which i think are the unused ports maybe? I will post a screen shot later. I wish windows would just let me manage each port specifically (not the device plugged into it). Do you have any other ideas?

**Brib3** · 06-05-2009, 06:00 PM

I have the same problem with an EEEPC. What I wanted to do is getting usb cable extension and perform some modifications on it. Simply cut the + wire in that cable and attach a relay in between that would engage when the car is turned on.