I have a need to turn USB power off (and on) using a script or a piece of software. Ideally it should be possible to turn each port off/on separately, but also turning power off/on from all ports at once is sufficient. The machine I am using is Mac Mini. Anyone has a solution for this?
By USB power I mean Vbus, the 5V/500mA connection. I understand that the data connection is also turned down and it is fine, but it is not enough for me that the data connection is down and Vbus remains powered. This need comes from the need to keep mobile phones constantly connected for automatic testing. Some device/battery combinations do not like to be constantly connected and batteries start swelling in less than a year.
I recognize that multiple variations of this question are around. So far no solution that I could use. I'll list here my findings so far:
it is possible to accomplish this by using external self powered USB HUB and controlling it's power. However, this is not an option for me (even quality hubs have caused other problems in my use).
it is possible to disable USB by removing .kext files. Among other sources it is explained in OS X Security configuration document. However this requires reboot and I am not sure if it really disables USB power or just data.
there are many claims that it just is not possible. However, OS X itself does it when it detects a device that consumes too much power, so there is at least hardware support. This error message is copied from /System/Library/Extension/IOUSBFamily.kext/Contents/Resources/English.lproj/Localizable.strings: "Unplug the device using too much power to re-enable USB devices." (of course I don't know if the disabling is done by turning off USB power, but I would assume it is natural action for the device that consumes too much of it).
it seems that on macbook the USB ports are normally powered even when the laptop is sleeping. While this is not solving my issue, it is kind of related.
The reason why I need this is that I have a test system where multiple devices are plugged in to a mac mini. The devices also charge over USB. It has turned out that if the device is connected all the time to a charger, it's battery is swollen in about a year, which makes the device unusable, insecure and potentially dangerous. Turning the power off when not needed, would significantly extend devices life.