(Low) Power Consumption for USB Flash Drives

Many thanks for your continued supply of quality USB Flash Drive products. I bet I’ve got at least a dozen or so of them around here. This is more of a general question then against a specific SanDisk USB flash drive used on a Smartphone in USB-OTG mode. In order to keep the question simple lets use:

SanDisk Ultra USB flash drive, 128 GB, Black (SDCZ48-128G-A46)

And to test this drive(s) lets use:


The following:


defines the amount of power available to a consuming device plugged into a USB port.

According to this specification the maximum amount of current provided from a Smartphone USB 2.0 OTG port is 500mA (2.5W), 900mA for the USB 3.0 (4.5W) port.

Looking at a handful of USB flash drives here I see something around 0.04A for around 250mW consumed. Depending on what the drive is doing, read or write, that can vary around some. Sometimes the drive will consume up to 450mW. Having said that some USB Flash Drives draw considerably more then that. The SDCZ48-128G-A46 can get up to 0.18A or even 0.20A resulting in a full 1W of power. So it’s kinda all over the place.

There are some Flash Drive ads that claim “low power” but nowhere indicate what that means. Saying that your Flash Drive is within the USB specs is kinda dodging the issue. So, is there somewhere in the published specifications for your USB Flash Drives that detail the expected power consumption of your USB Flash Drive products?


I’m also looking for power consumption information from *any* manufacturer. I tried to use a 32Gb Toshiba stick in my car, but it requires too much power. My next attempt was a Cruzer Fit 128Gb but I gather the capacity is too high, frustratingly. I don’t want to buy a 32Gb Cruzer Fit if the next one I try to use has the same issue - seems like a waste of money.