USB power question
I'm running a powered USB hub. The power is coming from my opus 150. My current hub has 4 ports and (of course) now I have more than 4 USB devices. If I plug another hub into one of the ports on my current hub, the power will come from the first hub's power (the opus) and not the USB bus (through the mobo), right?
I ask because getting power through the 5v will cut the power when the computer goes to standby. But if the power's flowing from the USB bus, it will stay active during standby. The goal here is to keep things shutting down without going through the hassle of tapping another 5v line from the Opus.
I imagine, after your car turns off and the 5V line from the Opus goes away, your USB hub (either one) would still be able to use a small amount of standby power because it is still available.
Look here: http://www.fmev.com/opusmod1.htm
The hub has a physical switch for either bus powered or self-powered. When the switch is set to self-powered and you pull the plug, all the devices shut down rather than default to bus powered.
I also know this because when the switch is set to bus-powered and the computer goes to standby, the light on the hub stays on and the devices retain power. When the switch is set to self-powered and the computer goes to standby, the light on the hub goes off and so do the individual devices.
The hub itself may use some minimal amount of power from the bus, but I'm not worried about that. If anything, the devices are the power hogs I'm worried about, the hubs themselves wont drain the car battery so quickly.
You don't want to get power only from the USB cable. That usually restricts you to 1.1 or fewer than 3 devices on the hub.