Conditioning a cell phone battery properly is a process that every purchaser of a new cell phone should follow. Too often, though, new cell phone owners do not follow a proper battery conditioning regimen, resulting in a bricked battery that cannot hold a charge. If you properly condition the battery, it should provide years of use.
Assemble your cell phone as directed. In nearly all cases, your cell phone battery will be partially charged to begin with. Do not plug in your cell phone right away, instead use it normally until the battery is completely discharged. (If you improperly charge your cell phone the first couple of times out, you can easily ruin the battery.)
Plug your cell phone, battery intact, into a wall charger. Do not charge your cell phone via USB or a car charger the first time out, as the voltage will not be the same. To condition a cell phone battery properly, use the original equipment charger with the proper voltage.
Use your cell phone as normal, now that it is fully charged. To condition a brand new cell phone, try not to use media or web-heavy functions straight off the bat that will drain the battery quickly. You want the battery to discharge the first few times at a slow, even rate.
Drain the battery fully before plugging the cell phone in. Do not fall into temptation to plug the cell phone in a second time before the battery is fully drained. While this will not damage your cell phone or battery during standard use, you need to properly condition the cell phone battery by draining it completely before plugging in.
Repeat the process four or five more times before even thinking about plugging in your cell phone when you still have battery power left. After completing proper cell phone battery conditioning, it will not hurt your cell phone battery to plug the cell phone in every night or to convenient power sources such as USB ports during the day. Conditioned cell phone batteries are meant to be able to catch a few minutes of charge as needed, but it is the first few days that are vital to good conditioning.
Continue to drain your cell phone battery completely before plugging it in at every available opportunity. Regardless of the age or conditioning of your cell phone battery, it will always last longer over time when discharged fully before charging again. Don't obsess over it to the point where it affects the way you use your phone; $35 for a new cell phone battery is not the end of the world.
Some cell phone batteries are defective from the onset. If your cell phone's battery cannot hold a charge even with proper conditioning, contact your carrier. It will be replaced free of charge under warranty.
Always use a charger with the correct voltage rating. Even if the charger's connector is the same size, using a charger with too much power can damage your battery or cell phone.