The charger also says that it has an output of 355 mAmps at 3.7 volts. So I can calculate how much of the power goes into the battery of my mobile phone. Well that is a bit disappointing. It seems that quite a lot of the energy is being wasted. My mobile is cool, but the charger is not very efficient and does get quite hot when I use it to recharge the phone.
Power is the rate of doing work.
So every second it is charging the phone, it uses 4.83 joules of energy, but only puts 1.31 joules into the battery. The other 3.52 joules per second is wasted. I know this because the battery also gets hot by the time it is fully charged. Some of the electrical energy is converted into chemical energy in the battery and the rest is wasted as heat. Copyright 1997 - 2000 Gondar Design.