Inside Android, how to extend your battery life

Howdy!  It's me again, and this week we're gonna talk about something near and dear to all of us -- battery life.  It's always at the tip of everyone's tongue (especially as new phones are released), and all the information out there is enough to make a person lose his or her mind.  Hopefully together we can work through it all, separate the fact from the fiction, and figure out how to keep everything out of the red.

Prepare your beverages, smoke 'em if you got 'em, and follow the jump so we can figure this out together.

Where we all need to start is with the realization that Android devices aren't phones. They're tiny little laptops with voice capability.  Those of us coming from feature phones (I hate the word dumb phone, you won't see it here again) or BlackBerries are probably shocked at the amount of juice these phones tiny laptops can suck up in a short amount of time.  On the other hand, folks from the WinMo, Pre or iPhone camp already knew battery life is, and always will be an issue with devices that are so feature-rich.

Another thing to remember is that if you've just got your new Android phone, you probably haven't given it much of a chance to sit still unless you're asleep :)  Once you're done setting it all up and checking out all the coolness that oozes out of it, battery life will get a little better.

Charging it up

Charging the HTC Hero

Straight and to the point -- you'll have to charge your Android phone at least once every day.  Get into the habit of hooking it to the charger at night before you go to sleep.  I wish I could tell you of some magical trick that gets you two or more days out of a battery without killing off everything that makes the phone worth having, but I can't.  If you're the type who never puts your phone down, you might even need to charge more than once a day.  Unless you want a much bigger device to hold a much bigger battery you're going to have to deal with
charging more often that you would like.  On the average though, using the tips you find here and elsewhere across the internet you'll probably manage to find a way to get through a full day on a single charge.  Of course a spare battery and charger or an extended battery is always a wise investment.

Conditioning the battery

You'll see that in a lot of various help forums and Android fan sites people talk about conditioning a new battery.  Not needed.  I won't bore everyone with the technical mumbo jumbo about battery types and manufacturer recommendations, you can find those HERE.  (Isn't it sad that I even have pages like that bookmarked? I need more hobbies!)  In plain English you do not need to cycle the battery in your new phone.  Charge it when you're done using it, try not to let it get too low too often, and try not to leave it on the charger more often than necessary.  Yes, there are complicated overcharge protection schemes in the battery charging circuit, but the battery itself will last longer if it doesn't sit with a full charge too often.  My advice stands -- charge it every night, take it off the charger every morning, and if you know you'll have a bit of "phone down time" it doesn't hurt to partially charge it throughout the day.  The battery is only designed to last about a year anyway, so rather than try to squeeze two more weeks of life from it just enjoy the year by using it.

After all that, there is a reason to condition your phone itself via the battery and charger.  A lithium ion battery (the kind in modern cell phones) has a memory.  Android reads this memory and translates it into human readable information -- the battery meter.  Every once in a while, it's fine to let the phone run down the whole way and then recharge. This helps keep the battery meter and the battery's actual memory on the same page and give a more accurate reading for battery life. If you're the geeky type and have rooted your phone, you can delete /data/system/batterystats.bin and reboot to do the same thing. (There should be an option for this in your Recovery module, if you're not running stock.)

Tips to save battery life

Charge battery Android

There are some things you can do to improve your battery life.  Most of these are common sense, and the folks in the forums have done a fine job covering some of them, but let's list them here in a nice and easy to read consolidated post.

Screen brightness

The screen on your phone is going to use the most battery.  It's  a big power hungry beast.  Always use auto-brightness if you can.  If your model doesn't have an auto brightness setting, pick something sensible for a default and work your way up.  I suggest starting at 30 percent and see if it suits you. 

Also remember to set your screen timeout -- as in the amount of time of inactivity before your screen goes dark.  Having the timeout set longer than 1 minute is just asking for trouble.  On the other hand, the inconvenience of having it set to 15 seconds isn't worth the hassle of unlocking the phone every time you touch it.  Thirty seconds or 1 minute is pretty sensible and should be a good starting point.

Android powercontrol widget

If you have a phone with an LED screen, you'll find auto brightness doesn't work well outside.  Hopefully this is something that science can figure out, but for now we can use the power control widget (sorry guys and gals stuck on Android 1.5, I feel for ya).  The screen brightness button has three settings -- think of them as low, medium and high.  The "high" setting cranks the screen to the max for use outside, the medium is a nice setting for indoor use, and the low works well in the dark listening to podcasts in your undies under the blankets.

Desktop background

Yes, those live wallpapers are cool as heck.  They also use some battery.  Not a lot considering what they do and their special effects, but enough to warrant discussion.  Anytime your screen is on, the live wallpapers are running.  Displaying them on the screen uses precious juice.  The live wallpaperss also use the processor, which also uses up the juice.  Again -- these aren't the battery hogs a lot of folks make them out to be, but every little bit counts.

An interesting note - if your phone uses an LED screen, dark wallpapers use less battery to display than light.  Not enough for me to worry about the color of my background, but I'm tossing it out there for the folks who want to squeeze every last drop. So here ya go, have a cool one on me :)

Wallpaper for Android

click me for the full res version!


When GPS is on, it uses the juice.  HARD. I don't mean when the setting is on, I mean when it's actually being used.  There are two ways to deal with this.  The simplest is to just shut GPS off unless you need it.  (Power control widget FTW!) The other way is to keep an eye on your status bar.  When GPS is running, you'll see the icon that looks like Jerry lost his mind and is using his satellite dish to communicate with the aliens. Not really, that was only once and I'm sure someone slipped something into my drink.  This icon is what we're talking about:

Android Maps GPS

If you see it, your phone is searching for GPS satellites and will draw power like nobody's business.  Sometimes we want or need this.  Looking at Maps, or checking into your favorite club with Foursquare, these kind of things. Any other times we don't want it running. If you see it's stuck on, or is starting and stopping when you think it shouldn't be, that's something you need to investigate.  We'll talk more about how to investigate a bit later.

WiFi, 3G, and how it affects things

The second biggest battery killer (after the screen), and the one most apt to cause battery life problems is the 3G radio in your phone.  Looking at the sky and determining which signal to lock on to, and when to switch, is a huge drain on your battery.  You can test this yourself.  Spend a day outside doing some drinking doing some healthy activities and check your battery life.  The next day, spend it inside your cube at work, or deep in your basement where the signal sucks.  Your battery life suffers.  A lot. 

Believe it or not, the WiFi radio uses a lot less battery.  A big part of this is the way it locks on to a signal and doesn't switch until it's told to, or the signal degrades enough that a proper connection can't be maintained. We can use this to our advantage, because that's what we do -- exploit everything we learned from the Science Channel to our own benefit :)

If you find you're having 3G signal issues in a place you spend a good portion of your time, invest in a cheap wireless G router.

Wireless G?  Are you crazy?  I want N!

If you have one already for other things like a computer or the toaster from Star Trek, N is good.  It's seven letters more than G for goodness sake :)  Just make sure to fiddle with mixed mode so your phone can connect and call it done.  But if you DON'T already have a WiFi router, a $50 router from WalMart will provide a connection faster than your phone can use.  Even if you have wireless N on your phone, it can't process the information as fast as the router can toss it out.  Save the coin, spend it in the Market.

Once you're connected to WiFi, have a look at some settings.  The first one we want to look at is WiFi sleep policy.  To get there, open the settings on your phone and hit Wireless and networks, Wi-Fi settings, and hit the menu button. Press Advanced, and have a look at the pictures below

WiFi Settings AndroidWiFi sleep policy Android

Pick Wi-Fi sleep policy, and set it to Never.  Yep, this sounds like it would use MORE battery, but it won't.  When WiFi is on, 3G is off.  When your screen is off, and WiFi is set to shut down, 3G has to kick in to get notifications, check mail, etc.  Leaving WiFi on while the screen is off keeps the power hungry 3G radio off and forces it to behave.

Another thing to consider is disabling the "Always on" setting under mobile networks if you have a CDMA device.  You'll find it under settings, Wireless and networks, Mobile Networks.  Enable Always on is set by default.  You can shut this down.  Look at the pics for a second

Android always on mobileAndroid mobile warning

See that warning in the second pic?  That means you're not going to get much use out of third-party apps that need to stay connected, and even some built in Android apps don't play very nice.  This is because we told the phone to shut off the data connection.  You'll still get phone calls and text messages, but the rest will be hit or miss. In my opinion this is only useful when you have a bad 3G data connection and no WiFi to mooch off of.

If you're using a GSM phone, you might have a battery-saver, too.  Under settings, Wireless and networks, Mobile Networks as well.  You can shut the 3G radio off and force the phone to use 2G connections only.  Look at the pic below to see what I'm talking about.

Android 2G setting

These tricks won't help if your voice signal is weak.  Those bars in your status bar are a measure of voice signal strength.  I you see them stay very low most of the time, or always seem to jump back and forth, you'll need to look at your actual signal strength.  You can do this under settings, About phone, Status, Signal strength.  Look at mine below:

Android signal strength

If yours looks like this (a number lower than -95...negative numbers, -100 is lower than -95) then you have issues.  My issue is living out in the sticks and trying to get a T-Mobile signal :)  One more tower T-Mo, please...just one more tower.  If your phone signal strength stays like this ALL the time, head back to your carrier and let them have a look.  If it's just in certain areas, look into a femtocell.  Your carrier can provide one, and are usually pretty helpful about getting you one with minimal costs.  They want to keep your business, so good signal where you live or work is important to them too.

Task killers

Ugh.  These two words will haunt me 'till I die I think. Read this. Don't worry, we won't go on with out you.

Back already?  Good.  Now you have a better understand of task killers, and why when and how to use or not use them.  If you decide to use one, make it helpful here, too.  Anytime you run an app that uses your camera, open the task killer and make sure it's closed when your done using it.  This could be placebo effect, but I've found a big difference by killing off things like barcode scanners and Obama Camera when I'm done using them.  YMMV.  But hey, if you wanna roll with the task killer, what's it hurt?  In my opinion, you're better off not using one if your only need is to try to save battery.

Android task killer


So you think you have a problem, where the heck do you look to find it?  First we're gonna talk to the good people still suffering with Cupcake.  If you're running something lower Android 1.5, update your phone for goodness sakes.

Spare Parts

Android spare parts

Market Link | AppBrain
spare parts QR code

Download it from the market.  Open it up, and press Battery History.  Look at the pics below:

spare partsspare parts battery stats

Look through these settings and see what's been using the most battery resources.  If it looks like something that shouldn't be using so much of it, fire off a question in the forums.  We've set up a special thread in the forums to use just for these kinds of questions, where we can get a bit more in depth than we could in the comments.  We still love to hear your comments of course, so feel free to say hey down below even if you had a problem to post in the thread.

Now if you're running eclair, there's a different way to check all this out.  Menu, settings, About phone, Battery use. 

Nexus one battery stats

Notice 14 + hours since off the charger, and 73 percent battery left.  You can do this, too.

Again, have a look, and if anything seems out of the ordinary, throw it out to the forums, and we'll all dig together.  And if you're lucky enough to have had issues and solved them, feel free to hang out there and jump right in :)

It's impossible for you to get the same battery life you expect from an old Blackberry Curve or that even older (and just slightly less feature rich *zing, I kid, I kid -- don't knee me, Kevin!*) Moto c139, so don't even think about it. But hopefully some of these ideas can help you stay running a little longer before you're scrambling for a micro USB cable.  In any case, none of it will hurt :)

Next week y'all,