If the
E-book Reader Matrix is correct the batteries are similar in size (Amazon 1530mAh; iLiad 20% larger than the original 1100mAh). The Kindle is the 2nd most power hungry E-Ink reader, but there is no doubt that iRex would have sold many more iLiads if it lasted as long on a charge as the Kindle and had a quick wake-up hibernate mode like the Kindle.