%0 Journal Article %T Optimization of efficiency and energy density of passive micro fuel cells and galvanic hydrogen generators %A Robert Hahn %A Stefan Wagner %A Steffen Krumbholz %A Herbert Reichl %J Computer Science %D 2008 %I arXiv %X A PEM micro fuel cell system is described which is based on self-breathing PEM micro fuel cells in the power range between 1 mW and 1W. Hydrogen is supplied with on-demand hydrogen production with help of a galvanic cell, that produces hydrogen when Zn reacts with water. The system can be used as a battery replacement for low power applications and has the potential to improve the run time of autonomous systems. The efficiency has been investigated as function of fuel cell construction and tested for several load profiles. %U http://arxiv.org/abs/0805.0939v1