*Update to below article* I have heard that charging battery full and letting it die out, will do more harm to your battery. It is in your best interest not to give a full charge to the battery on first use and every use. Just like the Toyota Prius battery, it is a wise thing to charge to 80%, and then when it get’s low charge it again. Just look at the below photo of a Samsung Ultra-book bios. The photo shows the option of allowing the battery only to charge to 80% and not any further, this will allow the overall battery life to be extended so you don’t have to end up paying a lot of money to go buy a new battery. Laptop and Galaxy S4 batteries both cost a lot.
That full charge and deplete that you heard about on first use is for older battery technology, not new technology.
That advice refers to nickel hybrid and cadmium batteries which haven’t been used in phones for 10 years now.
You should only completely deplete your battery once every 45 days, which is recommended by manufacturers. Below is a screenshot of my Galaxy S4, and it lasts me on average 3 days before I have to recharge again. I always avoid keeping it in the charger after 95% or sleeping overnight with it in the wall charger, as that will harm it. Some people say the battery itself, even has additional safeties to prevent over charging and under discharging. But I’d rather not overcharge it.
To charge the battery for Galaxy S4, the experts say charge it for four hours. This will fully charge it. Then let it run right down and die, and repeat two more times. This will get the optimum performannce from the battery of Galaxy S4. Hope it helps. If you wish to improve battery life, turn off unnecessary features or apps that sync constantly. Disable Gmail auto sync to save battery. See my other articles on flashing a custom rom, that is if you want to get the kind of battery life that I get. I get like close to 3 days battery life on stock battery, using a custom rom and Quad Core Manager to shut off some of the cores when I don’t need them.
Key here is to charge your phone less often so your battery doesn’t take a beating. Your battery will last longer if you charge it less of ten.