From CruisersWiki

Much of this article needs to be rewritten as there seems to be some confusion between Ah and Wh. The small table of various loads lists a phone charger at 2amps comparing it to half as much usage as a refrigerator. Obviously your phone uses much less energy than a fridge/freezer. The problem here is that the phone is drawing 2 amps at 5v while the fridge is drawing 4amps at 120v. Multiplying these together gives the respective wattages. You can not compare amp hours without taking into consideration the voltage the devices are operating at. 2a*5v= 10watt phone charger 4a*120v=480watt fridge.