Most of the modern robots that exist use a type of lead acid battery as a power source. Others, meanwhile, are directly plugged to an electric outlet. Currently, scientists are working on alternative power sources. Some of these potential energy sources are compressed air canisters, flywheel energy storage, organic garbage, faeces, and radioactive sources.
AA Battery Power Source
Of these possible alternatives, the use of faeces could prove to be interesting within the context of the military. The faeces of small combat groups could be used to provide the energy requirements of their unit’s robotic assistant. Organic garbage, on the other hand, could produce energy through anaerobic digestion.