The lack of a true "standby mode" is the real culprit. If you read with the Edge on your lap (which, given its weight, is necessary when not at a table), every touch of the LCD side against your knee, even when it is "off" is registered and presumably draws power. This is also a problem for using the eBook side - I was finding that highlighting wasn't working on my eBooks and the problem turned out to be that the LCD side, though off, was being constantly triggered by resting on my knee, which was using up all the processor's resources and leaving nothing to run the eBook side. The LCD should really go off when you turn it off.