In mobile phone battery chemical energy is converted to electrical energy for usage as a power source for the phone. It is a sealed bag which contains anode, cathode sheets and electrolyte. The capacity of these batteries is expressed by milliampere Hour (mAh) which is a unit of electric charge.
Mobile phone batteries are normally available in 2650 mAh, 3100 mAh, 3130 mAh, 3500 mAh, 4000 mAh, 4200 mAh, 5000 mAh and 850 mAh. The higher value of mAh shows that how long the current can be withdrawn from this battery. The stand by and talk time of a mobile phone are determined by the mAh value of the battery.
The battery type could be Lithium Polymer, Lithium-Ion, Nickel Metal Hydride and Nickel Cadmium.
Battery life is the amount of time the device runs before it needs to be charged.