## Why Does My Phone Battery Die So Fast?

Why do batteries die? And, why can they only be recharged so many times before they won’t hold a useful amount of charge?

And this same question has probably crossed the mind of every cellphone user trying to send one last text before the screen blinks off.

Research, like mine, continues around the world to make batteries that charge faster, last longer, and can be recharged and discharged many more times than today’s.

But as much as you and I would like, it’s impossible to make a truly everlasting battery. I have taught thermodynamics for more than 30 years.

So far, there is nothing that suggests we can break the fundamental laws of science to get that elusive battery.

Battery scientists and engineers call the main problem “capacity fade.

Regular people wonder about it with questions like “Why won’t my battery hold a charge?” and complaints like “I just recharged this thing and it’s already out again!

It’s a result of the second law of thermodynamics, which states that whenever some real process happens, it creates a certain amount of wasted energy along the way that can never be recovered.

Any time a battery is charged or discharged, there’s a little bit of wasted energy – a little bit of wasted capacity in the battery that cannot be recovered.

To envision how this works, think about battery use like transferring water between two cups.

Using a battery is like emptying the water from one cup into the other, and charging the battery involves pouring the water back into the first cup.

Even if you do it one or two times without spilling a drop, there’s always just a little tiny bit left in each cup that you can’t pour out.

Now imagine pouring back and forth hundreds or even thousands of times over a period of two or three years (for a cellphone battery) or 10 to 20 years (for an electric car).

Over time, all the thousands of little and big things that go wrong add up to quite a bit of water going missing. Even spilling a barely visible drop – say one-tenth of a milliliter – adds up to an entire liter if it happens 10,000 times.

That doesn’t even include the possibility of one cup failing in some way that loses even more water – like springing a leak or heating up and causing evaporation.

Just as water inevitably goes missing when pouring from one cup to another, more energy is required to charge the battery than it actually stores, and less energy comes out than is stored in it.

The proportion of wasted energy to stored energy grows over time.

In fact, the more you use a battery, the more energy gets wasted, and the sooner the battery will reach a point where it’s dead and can’t usefully be recharged.

I and others are studying ways to have those discharging-recharging cycles run more smoothly to reduce the amount of waste, but the second law of thermodynamics will always make sure that there’s no way to get rid of it entirely.

Pass it on: Popular Science

## 3 Ways To Cure The Cell Phone Dead Zone At Home

Can you hear me?” “Can you hear me now?” If most of your cellphone conversations begin this way — or if you’ve taken to hanging out a window just to get a signal — you’re not alone.

Spotty cellphone service can be especially frustrating when you have full bars in your building’s lobby or hallway but one measly bar as soon as you set foot inside your home.

It turns out, there are good explanations for why this occurs (no, the cellphone gods aren’t trying to punish you for posting too many selfies) and solutions that renters can easily implement. Here’s how.

Cause #1: The position of your building’s cellphone antenna

Cell carriers in all major cities position their cell sites close to the ground because that’s where most of the people are,” says Graham Caparulo, principal consultant for Diligex, a New York, NY–based managed IT services provider.

On the corners of buildings, you’ll see them 20 to 30 feet up, and they’re angled toward the street.” That doesn’t do you much good, especially if you live on the 30th floor of a high-rise.

Cause #2: Building materials can block radio signals

Tinted windows (especially the ones found on “green buildings”), concrete, and metal all interfere with cellphone reception — which is why you can often get more bars if you hold your phone out your window or step onto a balcony.

Cause #3: You live in a densely populated area

Have you ever noticed that your service is slower at night or on weekends, or when you attend a packed basketball game? The more people using a network, the slower it runs.

Each cell tower only has limited radio channels it can use,” says Caparulo. “When it’s full, you’ll have bars but can’t make a call or use data.

Solution #1: Invest in a cellphone booster

Invest” is the right word here, because a cell signal booster will typically set you back between \$400 and \$1,000.

A traditional cell signal booster takes in a signal on one end, amplifies it, and spits it out on the other end,” says Caparulo, who cautions that you have to have a good signal to work with in the first place, which may mean putting the booster’s antenna outside your window — a no-no in some apartment buildings.

Solution #2: Enlist a femtocell

A femtocell, also called a microcell, basically uses your Internet connection to back up your cellphone,” says Caparulo.

The device plugs right into your modem or router and uses your Internet connection as a cell signal booster.

Solution #3: Enable Wi-Fi calling on your smartphone

This feature, available on the iPhone 6 series and many Android phones, allows your phone to use your in-home Wi-Fi connection to make calls. (On the iPhone 6, go to “Settings,” then “Phone,” and it should be the first option.)