Power consumption or bad battery

[cahlucas]

Hi all,
Recently my G2 has a problem with the battery. After being fully charged and not used for about a week, the calculator no longer turns on when you press [On]. After charging it works again, but the problem remains. This is the 2nd time this has happened, I never had this problem before. The calculator is about two and a half years old. What could be the reason why the battery lasts so short? Has anyone had the same experience in the past, and has a solution been found? Gladly, I look forward to an answer. Sincerely, Karel.