Before the upgrade my battery was running completey out. One minute I would be reading - the next the kobo would be dead. Usually at a really inconvenient time - ie just when I was getting to a good part! So then I would charge the kobo and finish reading from the computer screen - YUCK!
I am a fast reader. No idea how many page turns but I normally read a book from start to finish in a session. With my original Kobo I was unable to read a full book on a single charge which was extremely disappointing as I am not used to stopping until the book is finished.
That kobo was replaced and the second one (the one I have now) was much better. It still required charging every 2 or 3 days. So with the second kobo I was getting usually 2 books per charge - sometimes 3 books. Really depended on whether I was prepared to risk it running out on me.
I have only read 1 book since I did the upgrade and that didn't cause any further drop in the charge indicator.
I have just purchased another 5 books and so the kobo has had another charge tonight. It will be interesting to see how much I can read now before it needs charging again.