3. Charge your battery correctly, in accordance with its type. Most newer cell phones have lithium-ion batteries, while older ones generally have nickel-based batteries. Read the label on the back of the battery or in the technical specifications in the manual to determine which yours is.
*Nickel-based batteries (either NiCd or NiMH) suffer from a phenomenon known as the "memory effect." If you charge the battery partially enough times, eventually the battery "forgets" that it can charge fully. A nickel-based battery suffering from memory effect can be reconditioned, which requires the battery to be completely discharged, then completely recharged (sometimes several times). The appropriate length of time between reconditionings varies. A good rule to follow for nickel-battery cell-phones is to discharge them completely once every two to three weeks, and only when you have a charger available.
* Lithium ion batteries, on the other hand, do not suffer from the same memory effect. However, many devices that use lithium batteries have a battery meter, showing the user how much charge the battery has left. Starting with a battery's manufacture at the factory, lithium ions oxidize in the battery, shortening its life. After a certain amount of time, the battery exhibits slightly different electronic properties, which the device can only detect when the battery is discharged. This type of problem is known as a "virtual memory effect" and occurs when your battery meter can show a high charge, then suddenly drop to low charge when the battery is almost dead. Every thirty cumulative cycles, you should discharge lithium ion batteries until the phone gives a low battery warning, then recharge it. If you discharge lithium ion batteries to zero voltage, the internal safety circuit may open. In that case, a normal charger will be inadequate. Reconditioning ensures that the battery meter on a lithium ion cellphone is accurate (although it will not affect actual battery capacity).
*Regardless of the battery type, use only a charger rated for your battery, and discontinue use of a charger that causes the battery to heat up excessively.