The AA powersupply would give a max of about 500-600ma... which means it would power the card reader and have enough juice to let you use the full 500mA of one usb port on the hub if you really really wanted to... or of course all three ports on the hub if you're drawing less... but basically 500mA to go around as needed. Also keep in mind at that current level you're looking maybe 2-3hrs tops for really good AA batteries.