8 Essential Tips To Keep Your Phone's Battery Healthy
Thatphone in your pocket is a modern miracle. Ditto the laptop on your desk, the
tablet in your backpack, maybe even the watch on your wrist. And regardless of
what each is capable of, they all have one cornerstone component to thank, one
that you probably ought to know how to take care of: A battery.
The first step to knowing your device's battery is to
narrow down the kind. The first kind you might think of (and the kind you
probably grew up with) are nickel-metal hydride, or NiMH batteries.
These, generally, are the ones that look like a normal disposable batteries,
except you can plug them into a wall charger for some extra juice whenever your
TV remote dies.
The batteries in your modern-day gadgets—from iPhones to
laptops to Bluetooth headphones to tablets—are a different beast entirely.
These are lithium-ion (aka li-ion) batteries, and
they have some pretty significant advantages over NiMH and other rechargeable
batteries that came before. Lithium-ion batteries are also totally different
from straight-up lithium batteries, which aren't rechargeable.
That old saw about how you always need to charge you
battery all the way up, and use it until it's dead? Memory effect, as it's called, affects NiMH
batteries but it doesn't apply to your phone. In fact, you're phone's battery
hates when you do that. Similarly, lithium-ion batteries don't need to be
"calibrated" with a full charge and a full discharge when they're
new.
Li-ions can pack a lot of power into a small size, and
they don't lose too much of that energy to leakage when they're not in use.
It's a combination of these factors that make them great for your portable
gadgets.
How does a lithium-ion battery work?
All batteries work by having two electrodes—an anode anda cathode—with a bunch of a material called electrolyte between. When you plug
a battery into a completed circuit, a chemical reaction starts taking place at
the anode and electrons start building up over there. Those electrons want to
travel to the cathode, where it's less crowded, but the electrolyte between
these two parts keeps the electrons from taking the short way there. The only
way through is the circuit that the battery is crammed into, and those
electrons power your device in the process. Meanwhile, the positively charged
lithium ions the electrons leave behind travel through the electrolyte to meet
the electrons on the cathode side.
Onceall the electrons have made the trip, your battery is dead. Except! If you're
using a rechargeable battery like a lithium-ion, you can reverse the process.
If you dump energy into a circuit using a charger, you can force the reaction
to go in the other direction and get that electron party at the anode all
crowded again. Once your battery is recharged, it'll mostly stay that way until
there's something for it to power again, though all batteries leak some charge
over time.
What determines the capacity of the battery—how long it
can power your stuff—is the number of lithium ions that can nestle themselves
into the tiny, porous craters of the anode or the cathode. Over time, with
repeated charge the anode and the cathode degrade, and can't fit as many ions
as they used to. As that happens, the battery stops holding a charge as well as
it once did.
How does a lithium-ion battery recharge?
It's easy to think of charging a battery as though you're
filling a tub with "power." Just hook up the hose until it's full!
From the outside, that's exactly how it works, but on the inside it's a little
more nuanced.
A lithium-ion battery typically charges in two stages.First comes the process called constant current charging. This is the part that
really is pretty simple. The charger for your phone or tablet will apply a
steady current of electricity to the battery to get all those electrons back to
the anode. During this stage, the charger just decides how much power is coming
out of the firehose and starts spraying. The higher that constant current, the
faster the battery can charge. High-voltage quick chargers—like the ones that
are starting to come with a lot of new phones—take advantage of this first
stage to cram in the juice as quickly as possible (at the cost of a bit of
extra stress on the battery).
When the battery is 70 percent recharged, the procedurechanges and flips over to constant voltage charging. During this second stage,
the charger makes sure that the voltage—that is, the difference in current
between the battery and the charger—stays the same rather than keeping the
current constant. Practically, this means that as the battery gets closer to
full, the current the charger sends into it decreases. As the battery gets
full, the rate at which it charges slows down. Once you reach 100 percent, the
charge simply trickles in, just enough to account for the tiny, tiny bit of
charge your battery loses naturally over time.
So what about over charging? Is that something you need
to worry about? No. I talked to Andrew Goldberg, a technical writer for iFixit,
who explained why.
A thousand ways to die
No matter how many times you bring it back to life, your
battery will die someday, or at least degrade into a shadow of its former self.
That's unavoidable. Most lithium-ion batteries have a rated lifetime of
somewhere between 500 and 1,500 charge cycles.
One cycle is just one bout of discharging, but how much
energy you discharge in one go—a measure referred to as depth of discharge
(DoD)—matters bigtime. Lithium-ions really hate a deep depth of discharge.
According to Battery University,
a staggeringly exhaustive resource on the topic, a li-ion that goes through 100
percent DoD (the user runs it down all the way to zero before recharging) can
degrade to 70 percent of its original capacity in 300-500 cycles. With a DoD of 25 percent,
where the user plugs it in as soon as it gets to 75 percent remain, that same
battery could be charged up to 2,500 times before it starts to seriously
degrade.
What's far more dangerous to a battery's well-being is
heat. Lithium-ion batteries despise heat. A li-ion battery that's been exposed
to temperatures of around 100 degrees Fahrenheit for a year will lose about 40
percent of its overall charge capacity. At 75 degrees, it'll lose only about 20
percent.
Something that's not an issue is overcharging. Contrary
to what you might think (or have been told), leaving your phone or laptop
plugged in all the time is not bad for its battery. That's because your
gadgets, the batteries in them, and the chargers you attach them to are
actually pretty smart about the way they do business. Trickle charge—what your
battery gets when it's connected and full—is way less detrimental to the
battery's health than a larger discharge would be.
Meanwhile, a danger you might not be aware of is total
discharge. When your battery stops powering your phone, it doesn't mean it's
actually empty. It's not! Lithium-ion batteries only discharge most of the way,
mainly because when they discharge all the way they can get wildly unstable. If
a battery comes close to that danger zone, a protection circuit in the battery
will trip and kill the battery forever and for real, functionally destroying
the battery before it can discharge to a level where it's in danger of
exploding.
How do I take care of my preciouslithium-ion battery?
Now
that you know the basics about the little chunk of power that keeps your phone
going, here are some bite-sized practical tips to keep it healthy without
driving yourself insane.
It is not the end of the world if you don't unplug your
phone the second that it is charged. That charger is smarter than you give it
credit for. Leaving your phone on the charger all night (or all day) is far
better for your battery than running it down and charging it up.
Lithium-ion batteries don't respond well to being charged
all the way up and then run all the way down. They take much better to little
bits of charge here and there.
Don't worry about overcharging the batteries in yourgadgets, and especially don't worry about overcharging your laptop. What we
just said about phones applies here, too. And on and on top of that, many
laptops (most, in fact) are smart enough to cut the battery out of the charging
equation entirely once it's full. The battery just sits there patiently until
you need it or until it needs another little shock to top it off.
The biggest danger to your laptop battery—and your phonebattery and your tablet battery—isn't overcharging, but heat. And with that in
mind, it might be wise to pop out your laptop battery while you're plugged into
the wall, if you can. As Andrew from iFixit explains:
The
catch is that if you use the computer without the battery, you run the risk of
a shutdown in the case of a power outage or clumsiness with the power adapter.
Weigh your priorities.
If you can't or don't want to remove your laptop battery,
at least make sure you've got good airflow. Don't block cooling vents. Maybe
even pick up a fan with a stand.
Speaking of temperature, make sure you don't leave yourphone in a hot car all day. Or place it on top of your gaming PC. Or use it in
a sauna. Try to avoid wireless charging if you can, because the waste-heat
those chargers generate will also bake your battery. Also, beware of quick
chargers. While your phone and charger are generally smart enough to minimize damage
from high-voltage chargers, a lot of power super fast can generate extra heat.
And if you have to store a gadget or its battery for a while, do it in a cool
dry place.
If you're storing batteries, you give them about a half acharge first. They'll slowly lose their charge over time, and if it drops into
the true-zero danger zone, your battery will automatically trip its safety
circuit and kill itself for real before it can become unstable.
If you're borderline insane about your battery life,consider opting for gadgets that have removable batteries when you can. For one
thing, there's no faster way to "charge" a gadget than by swapping in
a fully charged battery. And if you can't avoid these bad battery practices, at
least you can start fresh by buying a fresh battery.
As Andrew from iFixit points out:
If you follow the most basic rules of thumb—don't go all the way from fullto empty if you can avoid it and minimize the exposure to heat as best youcan—you'll be fine. It's easy to obsess over battery care, to let charging
superstitions metastasize into obsessive ritual. But just remember two things:
1. Your gadgets and their batteries are designed to keep you from ruining
them. Lithium-ion batteries today are better, smarter, and more resilient than
the nickel-metal hydrides of yesteryear.
2. Your batteries are going to die. No amount of obsessive care will save
you from having to deal with a less capable battery a few years from now.
Invariably, we're all destined for the annoying endgame that comes when a
battery degrades, and you're either tethered to a charger, buying a replacement
battery, or buying a new gadget altogether. We've all been there before, and
we'll be there again. So long as you follow the most basic of guidelines, you
can maximize your distance from here to there.
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