How many gallons of gasoline would it take to charge an iPhone?

Re:How many gallons of gasoline would it take to charge an i... by wickedchicken on Wednesday February 08, 2012 @12:57PM (#3567604)

Gas has an incredible amount of energy density. You can do a fun calculation as follows:

If you believe this calculator, it takes 2419kJ to go 20km while cycling. (http://www.tribology-abc.com/calculators/cycling.htm)

A gallon of gas contains about 114,000BTU (http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent). Note that the Exxon diagram is 'per fillup' not per gallon.

So... http://www.wolframalpha.com/input/?i=%281%2F%28%282419kJ%2F2... yields 617MPG while biking.

It's approximate, but good to know that biking is roughly an order of magnitude more efficient than cars.

[ Parent | on HN ]

Re:How many gallons of gasoline would it take to charge an i... by iliis on Wednesday February 08, 2012 @01:24PM (#3567730)

Yes, bicycles are quite efficient. Not only compared to cars, but interestingly also to animals. While a normal human is quite bad at converting food into motion, the system bicycle+human is comparable to some of the most efficient animals. Now, if they had bicycles as well...

[Source: Dad, hobby-bicyclist/mechanic]

[ Parent | on HN ]

Re:How many gallons of gasoline would it take to charge an i... by cperciva on Wednesday February 08, 2012 @01:13PM (#3567675)

Considering that bicycle + cyclist is roughly an order of magnitude less massive than a car, that sounds about right. Of course, cars are also vastly more efficient at converting fuel into work than humans are.

[ Parent | on HN ]