If I accidentally leave a USB drive in my samsung galaxy S7+ it will drain the battery in a few hours even if it's not being used and the android goes "sleep".

Why is this and and how to prevent it? E.g., I don't need to use the USB port when I'm not using the tablet 99.9% of the time.

Also, the USB port seems to use a lot of battery in general even if I'm just playing a video off it or reading a pdf.

  • 4
    USB flash drives always draw power even in idle mode. How much depends on the flash drives. Some draw 0.5 W others up to 4W. This known to be a problem with laptops and of course even more with smartphones as their battery is even smaller. As the drawn power is a hardware property there is nothing you can do against except from disconnecting the flash drive
    – Robert
    Commented Sep 23, 2023 at 9:28
  • If your device is rooted, possible to limit
    – beeshyams
    Commented Sep 23, 2023 at 13:46
  • @Robert It is not a hardware problem to disable the USB port when the tablet goes to sleep. They can easily disable power to the USB port even if the drain is a "hardware property". (e.g., this involves an 0.0001c mosfet). If the USB is not being used it shouldn't require power and the OS knows if it's being used since it is using it. Even if the hardware itself isn't designed efficiently this doesn't mean the hardware on the tablet has to go along with it. As long as the power to the USB port can be controlled in software there should be a fix.
    – user14448
    Commented Sep 23, 2023 at 19:37
  • But before removing power Android would have to safely unmount it. And I am not sure if automatic unmounting is a common function. Usually it is the users choice when a disk is unmiunted. As only the user knows if the drive will be used in the near future or not.
    – Robert
    Commented Sep 23, 2023 at 21:09

1 Answer 1


As far as I know, there is no built-in option for that.

However, you could try the 7-day trial of Tasker, which automates any possible task you can think of as long as there is an internal API for it. In this case it would be turning off USB OTG while the screen is off.

Remember that your phone's battery is suited for devices with a very small power drain only, you may be able to connect an USB espresso machine with the OTG adapter but that doesn't mean it's a good idea at all.

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