How to prolong your cell phone battery's life span

Taylor Martin
 from  Concord, NC
| August 7, 2011

Ever since I made the jump from BlackBerry to countless other mobile platforms, I have been primarily displeased with battery life. Some platforms are clearly less power-hungry than others, but in all of my testing and probing, I have yet to find any device that truly matches the longevity of a 'Berry. Instead of charging my phone once every two or three days, I've been forced to charge my phones every day, if not twice per day.

In having to re-power my phones so much, I became worried about what it might be doing to the life span of my phones' batteries. (I'm not as worried about phones with removable batteries as those can be replaced pretty easily, but more so worried about what this may be doing to non-removable batteries in tablets or the iPhone.) Google searching for “the best way to prolong your phone's battery” will likely yield several different suggestions on how to properly care for your battery.

I've seen several articles and forums suggesting users let their phone fully discharge – to the point it powers itself down – before plugging the phone up, and charging it while powered off for anywhere from three to eight hours. Other sites suggest plugging your phone in every chance you get, not ever letting your phone fully discharge. Even speaking with associates at wireless stores can lead to some conflicting answers. So which is the correct method?

The fact is, your cell phone (and/or tablet) uses a Lithium-Ion (Li-Ion) battery. Replaceable or not, the Li-Ion battery in your device will not last forever. But with the proper care, you can make it last much longer. This is especially beneficial when batteries are not easily replaceable.

According to Battery University, it is best to keep the depth of discharge (DoD) small. This means that plugging your phone up often is the best method of keeping your phone charged. That said, leaving your phone plugged in too much or only letting it discharge a little before plugging it back in every time can be just as detrimental as fully discharging too often. Your best bet is to let your phone drain to 40 or 50 percent before plugging it back up, though charging before or after those thresholds are not bad either. Think of it as exercising your battery; too little or too much can both be bad.

When the battery in your phone or tablet is created, the manufacturer puts it through stress testing and it gets rated on the level of charge cycles it can withstand before it reaches "end of life." Usually these are rated between 500 and 1,000 charge cycles. Battery University provides a table that can help quantify how partial charges can affect battery life. Fully discharge your battery every time before plugging up and you may only see 500 charge cycles, but reduce the DoD from 100 to 25 percent and you might experience 2,500 cycles. Don't take these numbers as fact, but rather a rule to go by. "Specifying battery life by the number of discharge cycles is not complete by itself; equally if not more important are temperature conditions and charging voltages," says Battery University.

Keep in mind, too, that in use, your battery can lose calibration. It is also good practice to fully discharge your battery periodically and fully charge while powered off to recalibrate your Li-Ion cell. Letting your battery drain to a “zero” charge level will help display a more accurate battery charge level reading on your phone's display. Tech Republic also suggests keeping your batteries protected from excessive heat, stating, “Heat can overexcite the chemicals in your battery, shortening its overall lifespan.”

Despite what you may read and all of the different techniques out there for keeping your Li-Ion battery healthy and in great shape, the methods are pretty cut and dry. Here are some takeaways:

  • Charge your battery frequently
  • Don't leave your device plugged in all the time
  • Keep it protected from excessive heat
  • Fully discharge the battery every months or two for recalibration
  • Don't be afraid to use your battery