Windows 10 Thinkpad 10 tablet keeps providing power to usb port??

Hello again,

I am attempting to use my thinkpad 10 tablet ( Windows) as a car front end.

I am getting there ( ), but am still stuck by some problems.

One of these is power management.

I have various peripherals connected via a separately powered usb hub.

so........ I don't need any power to the hub from the tablet.

If I am not going to be away from the car for long, rather than shutting down the tab, I sleep it .

Althougth power to the tab and the powered hub is removed, the tablet still gives power to the hub from its battery reserve.

The hub has seven peripherals attached, so it can represent quite a drain to the tablet on battery.

I have tried to prevent usb ( selective suspend), and also tried to check for windows powering down any usb devices to save power in Device Manager.

Still, every time the car removes power, the usb port on the tablet is still active??

Has anybody any ideas?

-- by the way, I have no option in BIOS for usb power, and I also tried to make a USB cable DATA only- no luck ------

Many Thanks

Pootler