of course, they are completely ignoring the conversion efficiency of the fuel sources to electricity.<p>Let&#x27;s take diesel for instance, conversion efficiency of chemical energy to work for small engines can be about 30% at best, so a much more reasonable estimate for regular use is about 2.85 days rather than 9.5.<p>Now the interesting thing is that people have actually proposed using internal combustion engines and fuel as a replacement for batteries in electronic gadgets. to do so one uses tiny turbines micromachined using the same techniques to make microchips. One researcher working on this technology estimates that at max an energy density of 1500 Wh&#x2F;l could be achieved, which gets us a whopping 1.33 days of run time at regular use!
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