... to charge an iPhone? Propaganda yes...but interesting nonetheless: How many gallons of gasoline would it take to charge an iPhone? | ExxonMobil's Perspectives Blog
Ok lets do the Math...... 1 USG of average Unleaded Non-Oxygenated Gasoline has on average 120 KBTUs. That equates to 35.15 KWHours of energy. My iPad2 takes about 3 hours to charge up from my USB Port on my computer. USB can supply 5 Vdc@ .5Amps. so 25 Watts. For three Hours equals 75 WattHours. To charge from Dead to Full Charge. .0075 KwH into 35.15 KwH = 4686.66 Full Charges from a US Gallon of Gas... Of course this "Assumes" that you have 100% conversion of energy from Gasoline to electricity. when in actuality, this conversion is only about 35% efficient. So. 4686.33 * .35 = 1640 Full Charges.... plus a lot of heat going to Global Warming (all the extra energy is eventually dumped as heat) Now if you charge up once a Day, that would give you 1640/7=234.33 Weeks, or 4.5 Years of Operation of an iPad2..... ... YMMV....
Yeah, BT's Monkey expertise is a Major in both Communications & Cold with a Minor in Energy. He one those Monkeys that SM would be a far poorer place without.