Batteries have also been in the news --
Boeing's new 787 Dreamliner has been under fire for using batteries that
were…well, on fire. Such incidents underscore battery limitations,
though there are few black-and-white truths about battery behavior,
according to Isidor Buchmann, founder and CEO of Cadex Electronics and
author of “Batteries in a Portable World.”
So, what is going on in that battery of yours?
Under the Hood
All
batteries use a chemical reactions to generate current. For example,
the dry cell in a smoke detector or TV remote relies on a reaction
between manganese dioxide, zinc, and ammonium chloride. Potassium
hydroxide plays a role in alkaline batteries, while you'll find zinc
chloride in so-called "heavy-duty" batteries.
Despite the
name, heavy-duty batteries aren't superior to alkaline cells, which
typically last more than twice as long, according to manufacturer
Rayovac. In fact, one tip sometimes seen on Internet forums is true:
After using an alkaline in a device like a digital camera that puts a
heavy load on the battery, it still has plenty of life to give in a
low-drain device that requires a heavy-duty cell.
“Alkaline
increases resistance with usage,” Buchmann said. “You can continue using
them in a kitchen clock when they come out of the digital camera.”
Battery Safety
With occasional reports about battery fires and explosions, some people fear that rechargeable batteries are unsafe.
Although
nickel-metal-hydride (NiMH) and nickel-cadmium (NiCd) rechargeable
batteries are still in limited use, most modern rechargeable devices use
lithium-ion technology. And when you see news stories about burned
phones, laptops and airplanes, it's usually lithium-ion batteries which
are to blame. So are lithium-ion batteries really fire-prone?
Hirohito
Teraoka, director of Technical Marketing for FDK Twicell, says such
fires are rare. He also says that the solid-state lithium-ion polymer
batteries in your home devices are safer than the liquid lithium-ion
cells in the 787 Dreamliner.
“The
electrolyte inside [a commercial] lithium-ion battery is in liquid form
and is flammable, causing a risk if external or internal short circuits
occur,” Teraoka said. “[Consumer-grade] solid-state rechargeable lithium
batteries are considered safer than commercial lithium-ion batteries.”
To protect against sudden heat increases, or thermal runaway, these
batteries include safety features such as circuit interrupts, electronic
"fuses," and vents that allow gases to escape before they can burst
into flame.
Battery Memory
Have you heard
stories about rechargeable battery "memory effect"? In a nutshell: If
you don't fully discharge your battery before recharging it, the battery
will only "remember" part of its capacity, and the run time will
suffer.
This myth does have a
basis in fact. NiCd batteries, when discharged repeatedly to the same
level before recharging, eventually lose their full capacity.
Fortunately, NiCd batteries are rarely -- if ever -- used in consumer
devices anymore, and so your Samsumg Galaxy is immune to this ailment.
“Memory is only present in nickel-based batteries,” Buchmann said.
On the
other hand, it’s true that your laptop’s battery periodically needs
calibration with a full discharge/recharge cycle to get the best
performance. Buchmann said engineers call this effect "digital memory."
Unlike the memory effect in NiCd batteries, this doesn’t hurt the
battery's actual ability to charge. Instead, it might just keep your
device from using all the capacity available until it's re-calibrated.
Battery chargers themselves can be another source of confusion.
Consider
electric cars, for example. High-quality modern chargers are
"intelligent," charging quickly at first, then slowing and stopping as
necessary. However, Teraoka said high-powered quick-charge stations
might reduce the useful life of an electric vehicle's battery since it
can defeat the lithium-ion battery’s protection circuits. But not
everyone agrees: Manufacturers like Mitsubishi claim that drivers can
fast-charge regularly without significant issues.
Refrigeration and Recycling
You might know
the old "helpful hint" of storing batteries in a refrigerator to extend
their life. It turns out that this might not be so helpful after all.
Energizer claims refrigeration won't preserve a charge much better than
storage at room temperature, and the icebox's condensation can corrode a
battery, ending its life before its time. Buchmann concurs.
“The effect is moderate,” he said. Buchmann further says that keeping batteries above 86 degrees Fahrenheit can hasten aging.
On the
other hand, what you've heard about recycling batteries is true:
Materials in almost every type of battery -- especially rechargeables --
are an environmental concern.
Certain
types of rechargeable batteries might contain heavy metals such as
cadmium, lead and lithium, according to Jennifer Childress, director of
marketing at nonprofit Call2Recycle.
How about
household dry cells? Since 1996, when federal law eliminated mercury in
single-use batteries, Childress says most communities consider alkaline
batteries and their kin to be disposable in normal household waste.
Keeping Your Batteries Alive
Modern
batteries are larger and more efficient, but using all the bells and
whistles on a mobile device can still deplete its energy in short order.
Here are some best practices to maximize your battery's life:
A digital
screen is the largest drain on a device's battery. Turn down the
brightness as far as you feel comfortable with and set the screen sleep
interval to its shortest setting.
Limit or
close your background apps and disable "push" updates. Allowing your
calendar and email to update every five minutes can drain your phone
even when you're not using it.
Disable the
receivers or transmitters you aren't using. If you're not in a hotspot
or using a wireless headset, turn off your Wi-Fi and Bluetooth.
Use your device's "power saver" mode, which includes the manufacturer's optimum settings for preserving battery life.
Turn off
your phone or use its "Airplane Mode" if you'll be spending time in an
area without a strong cell signal. Phones will keep searching for a
signal even when asleep, consuming valuable power.
