Battery life with exam mode

[retoa]

Same problem with battery life in exam mode here in Switzerland.

Fortunately we don't need it, but sometimes a student activate it.
If the calculator stay in exam mode overnight, in the morning the battery is empty and you can not turn on the calculator.

As said for us it is not a problem as we don't have limitations during the exams (we have one part of the exam without calculator and one with graphical CAS calculator).