USB flash drives consume power from the PC, laptop, and tablets. I often left my flash drive connected to my Windows tablet but after letting it connected for a long time only the least amount of battery is used so I wanted to know that how much power does a flash drive consumes. I searched the internet about this and found these as results.
While the USB flash drive is idle it will drive the least amount of power from the host and while writing, the power usage increase to up to 3 times of the idle. USB 1.0 flash drive consumes approx 23 mA while the drive is idle and 34mA while reading or writing data. USB 2.0 flash drive requires 34 mA power when it’s idle but while writing any data to it consumes 105 mA power from the host. USB 3.0 is power convenient so it consumes 2.5 W of power while data transfer which is much lower than the previous versions.
If you keep the flash drive connected only till the transfer completes then you might save more because if the transfer rate is low as in USB 1.0 or 1.1 then it will take more time to transfer the data and you need to get it connected for more time than USB 2.0 or 3.0 flash drive, which means it will take less power.
The conclusion is that if you want to save more battery out of your tablet or laptop then you should use USB 3.0 flash drives and don’t let it connected to your tablet or laptop for a long time.