Could we run an electric car on electric eels? Could we run an electric car on a tank full of electric eels?
I've heard electric eels are around 400 to 500 volts and can keep shocking for up to an hour. They also have a 10 volt system to sense with, which might be good for the headlights and cd player.
 A: Well, believe it or not, eels have been used to power Christmas trees (youtube link), so powering an electric motor isn't quite out of the question. However, Eels emit that 400 V at 1 A = 400 Watts (though the youtube video says that the eel was emitting 800 Watts). An electric car requires over ten thousand Watts of power to operate. 
So in theory, you probably could do it, but the power would be intermittent at best and you would need a fair amount of eels. Plus feeding them might get more costly than the electricity you'd save.
A: The way every electric car works is by converting electrical energy into kinetic energy.  The externally released energy of a discharge of Electrophorus electricus has been studied and has been found to be around $17 \mu\mathrm J$ per discharge. Since kinetic energy is $E_k = \frac{1}{2}mv^2$, if we assume a combined driver+vehicle weight of 1000 kg, then that would give $v \approx 0.6$ m/hour given a wholly unrealistic 100% conversion efficiency.  These same researchers let the animal recover for around 3 minutes after each discharge and were able to get thousands of discharges.  So we can calculate that one could get 20 discharges every eel every hour.  (Multiple eels in case one were interested in going at higher speeds, e.g. as might be required for racing slugs or tree sloths.)
Bottom line: if you're really not in a hurry, then yes, you could power an electric car with electric eels.
