Abstract: The present invention relates to a method for monitoring the amount of fluid in a fluid container, wherein the amount of fluid contained in the fluid container is determined at a first moment in time, said step comprising reading out information provided on the fluid container, and wherein, at a second moment in time, the amount of fluid is determined that has been removed between said first and second moments in time, and wherein at least one quantity is stored, which is representative of the amount of fluid contained in the fluid container at said second moment in time. Furthermore, the invention relates to a fluid container comprising an information storage means which is adapted to have stored therein the amount of fluid contained in the fluid container or at least one other quantity that is representative of the amount of fluid contained in the fluid container. The invention additionally relates to a system for using such fluid containers.

Abstract: The present invention relates to a hybrid energy source (current/voltage source), wherein a fuel cell device and an energy storing device, e.g. a battery and/or a capacitor, are directly interconnected in parallel.