Dear Lifehacker, What is the deal with lithium-ion batteries (the kind found in smartphones and laptops)? I've heard lots of different things about how to take care of them, like that they need to be kept charged between 40 per cent and 80 percent, or that they should be drained completely and charged to 100 per cent. What is the ideal configuration to maintain a good battery life to battery health ratio? Sincerely, Befuddled About Batteries
Update: This post originally appeared on Lifehacker in January 2012. We've updated it to include the awesome video below from Techquickie.
Photo by Nicemonkey/Shutterstock
There is a lot of confusion surrounding this issue, mostly because lithium-ion batteries are different from older, nickel-based batteries (which suffered from a nasty memory effect not present in lithium-ion batteries). You're right, though -- charging them incorrectly can decrease their lifespan. Most lithium batteries should last you a few years, but improper care can decrease that lifespan, meaning that your battery will be unable to hold a charge -- or unable to hold as big a charge as it used to -- quicker.
So, to clear things up, we've rounded up some guidelines to extending your battery's health as much as possible. If you're more of a visual learner, the above video from Techquickie summarizes most of these, too. Here's what you should do:
Perform shallow discharges. Instead of discharging to 0 per cent all the time, lithium-ion batteries do best when you discharge them for a little bit, then charge them for a little bit. The table below, from Battery University, shows that discharges to 50 per cent are better for your battery's long-term life than, say, small discharges to 90 per cent or large discharges to 0 per cent (since the 50 per cent discharges provide the best number of cycles-to-usage ratio).
- Don't leave it fully charged. Similarly, lithium-ion batteries don't need to be charged all the way to 100 per cent. In fact, they'd prefer not to be -- so the 40 to 80 per cent rule you heard is a good guideline. When possible, keep it in that range to prolong its life as long as you can. And, if you do charge it to 100 per cent, don't leave it plugged in. This is something most of us do, but it's another activity that will degrade your battery's health.
- Fully discharge it once a month. This may seem contradictory, but hear us out. While lithium-ion batteries shouldn't be discharged regularly, most modern batteries are what's known as "smart batteries", which means that they can tell you how long you have until your battery dies (e.g. "2 hours, 15 minutes remaining"). This feature can get miscalibrated after a lot of shallow discharges. So, manufacturers recommend fully discharging your battery once a month to make sure this stays accurate.
- Keep it cool. Most people overlook this one. Excess heat is not only bad for your processor (and your lap), it harms your battery as well. Once again, see the table from Battery University below. A hot battery will degrade in health much quicker than a cool one. As such, we highly recommend using a laptop stand. When it comes to your phone, check out our previous Ask Lifehacker on keeping your phone temperature down.
Keep these things in mind and your battery will last longer. That said, you don't need to lie awake at night worrying about whether your battery's charging. Don't sacrifice practicality just to keep your battery alive -- if you're in a situation where you don't have a charger, it's OK to discharge it to 0 per cent, or to charge it up to 100 per cent if you want to get ready for a long plane ride.
Remember that your battery is going to die in a few years, no matter what you do -- even if you just let it sit on a shelf. These guidelines are just that -- guidelines to keep it healthy for as long as possible (and when it's dead, check out what do to when your battery doesn't last as long as it used to).
If you want a more detailed look at how lithium batteries work and how to take care of them, check out the links below from Battery University.
- How to Prolong Lithium-Based Batteries
- Charging Lithium-Ion Batteries
- How to Store Batteries
- When to Charge Table
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