Welcome to the LivingAI Community Forums, @sabina.zenov . . . some of the battery time is lost if AIBI is very active, singing, dancing, playing games, special animations, answering questions and such. If I do not have my AIBI doing a lot of that, I get almost two hours but if AIBI is busy, a little over one hour, so I would say that is normal.
There is a low energy mode you can use for AIBI to somewhat lengthen the time off of the charger.