How Many AA Batteries Would to Take to Power a Human?

Engineering & Science Humor - RF CafeThese engineering and science tech-centric jokes, song parodies, anecdotes and assorted humor have been collected from friends and websites across the Internet. I check back occasionally for new fodder, but it seems all the old content is reappearing all over (like this is). The humor is light-hearted and clean and sometimes slightly assaultive to the easily-offended, so you are forewarned. It is all workplace-safe.

Humor #1, #2, #3

So, how many AA batteries would it take to power a standard adult human for one day?

A Manganese/Alkaline AA cell it rated at about 2.4 amp-hours. If we assume 1.5 volts average this gives approximately 3.6 watt-hours (slightly optimistic). Since there are 3,600 seconds in an hour this is equivalent to 12,960 Joules.

A human consumes about 2,000 calories/day. A dietician calorie is equal to 1,000 engineering calories. A calorie is equal to 4.2 Joules. Therefore this is equivalent to 2,000 * 1,000 * 4.2 = 8.4 * 106 Joules per day.

Dividing one by the other you will need about 648 AA cells to power a human for one day.

This assumes that the power from the AA cell will go through the same inefficiencies as the chemical processes in a human. (A human runs at about 20% efficiency chemical energy to mechanical energy). If we can circumvent this inefficiency we would only need 20% of this number of cells - say 130 cells.

---From: Ben Gebeau

Related Pages on RF Cafe:

- Battery Drawings

- Battery Vendors

- Li-Po or Li-Poly Battery Characteristics

- Inside a 9-Volt Battery

- How Many AA Batteries Would to Take to Power a Human?

- Ray-O-Vac Ad, August 25, 1945, Saturday Evening Post