I agree with SolanO. My battery life experience with the Reader (using an SD card loaded with PDF full-page "graphics") is in some large enough level that I couldn't tell you. DEFINATELY draining too fast on your reader. I read through at least 20 connect e-books and experimented with 100's of 40+ page PDFs before my reader needed it's first recharge (the only other charging it got was the 1-2 minutes it was connected to the computer for downloads 2-3 times -- the rest I used a SD writer).
It's like the Blackberry days of lore (before they added everything and the kitchen sink to the BB) where it took so long to drain the battery compared to anything else that I would be in shock and literally have to search for my charger.