Electric power is volts times ampere (P = V i). When a car battery at 12 V is charged with 6 amp for 3 hours how much energy is delivered?
W = ⌡W . dt = W. ∆t = V i ∆t
= 12 V × 6 Amp × 3 × 3600 *
= 777 600 J = 777.6 kJ
Remark: Volt times ampere is also watts, 1 W = 1 V × 1 Amp.
