biological fuel and batteries

In the fuel cell, designed for amateur experiments (Fig. 6.6, a) using a mixture of sodium hydroxide ( NaOH), hydrogen peroxide (H2 O2 ), methanol and a catalyst plate (silver and platinum). Electromotive force the element of about 1.5 efficiency. 60 ... 80%. Hours motor consuming a current of 0.15 A, with a single filling element reaches 15 min.

Biological battery (Fig. 6.6, b) consists of 12 items, which are plastic containers with a diameter of 50 mm and a height of 100 in which powder poured rice flakes and the electrodes (anode and cathode). The bacteria (and ecological), propagated in this medium in the presence 
of water, give (at 12 vessels), a current of about 40 mA at a voltage of 6 V. Reserve nutrient medium is enough for half a year of continuous operation 
of the element.

Biological elements with a nutrient medium consisting of bananas and inorganic salts, feed during the day electronic devices, power to 3.7 W (0,76 V; 4,92 A). Bananas can be replaced with grapes, melon etc.