DI-2108-P power consumption

DI-2108-P power consumption

Hello,

I am using a DI-2108-P to record two 0-10V channels in stand alone mode, all other channels disabled. I am powering the device through the USB interface with a 5V battery supply.  The manual states that power consumption is <1W via USB interface. I find that without the USB drive inserted, the current draw is about .2A, so close enough to 1W. However, with the USB drive simply insert and not recording, the current draw increases to about .24A, which is about 1.2W. This difference is enough that my battery supply just barely doesn't last as long as I estimated. Besides the obvious answer of getting a bigger battery, I'm wondering if there is a configuration setting I might have overlooked or some other option for reducing power consumption. 

Thanks,
Adam