Battery in Android L

The next version of Android introduces battery-saving features for developers and users alike

You can never have enough battery power. Battery life is one of the main areas of smartphone performance in which there's still a huge amount of room for improvement. Batteries in the leading Android phones are getting bigger all the time, and that's one way to make things better. But the Android L developer preview also brings software improvements aimed to boost longevity, including new battery stats and a battery-saving mode for users, and tools to help developers make more battery-friendly apps.

Let's take a closer look.

First, let's look at the user-facing changes to power management in Android L. Under Settings > Battery you'll now see a projection of how long your battery has left, based on your recent usage. It'll appear after a few minutes of use, as the system gets a feel for how you're using your phone or tablet.


Next is battery saver mode, long included in manufacturer-customized Android phones, but new to the stock OS. It's found in Settings > Battery, under the overflow menu at the top right corner of the screen. Battery saver can be turned on automatically when your battery reaches a certain level, or enabled manually at any time. As we've seen in customized phones from Samsung, Sony, HTC, LG and others, this mode reduces the backlight and clocks down the CPU speed to save power.

Battery saver

This isn't an "ultra" or "extreme" battery saving mode, though, and as such all your apps are still available when it's turned on. (When it's enabled you'll see a persistent notification in your notification shade.)

Google's "Project Volta" also introduces a couple of important developer-focused power features, and these should eventually allow devs to create more battery-friendly apps.

The first is a power consumption analysis tool called Battery Historian, a new part of the Android SDK. Similar to the way developers can analyse graphical performance with the "Profile GPU rendering" tool, Battery Historian lets devs see detailed visualizations of the impact their app's actions have on a particular device's battery life.

Battery Historian

The new Job Scheduler in Android L is another important tool for developers that can help apps avoid waking up the device unnecessarily. Using this feature, programmers can set certain preconditions and deadlines for performing battery-intensive tasks. For instance, you might want to pull down a large amount of data, but only when an unmetered Wifi connection is available. Or you might want send data to a server within a deadline of 15 minutes. Setting deadlines allows the Job Scheduler to intelligently process job requests from various apps, and then wake the phone up and process several at once when it makes sense. By doing things this way, you avoid waking the OS up over and over again for each background task.

This is roughly comparable to the "queue background data" feature found on some Sony phones, which is designed to avoid unnecessary wake-ups by queuing up background data requests and processing them at set intervals. However Android L's Job Scheduler is a step beyond this, as devs themselves are allowed to set specific conditions and deadlines for their jobs.

Remember that what we're seeing in the current Android L developer preview isn't final, and it may well change between now and L's final release. It's a promising start, though, and the benefits should be seen across all Android L devices from this fall.

More: Everything you need to know about Android L, Android L Preview hands-on


Reader comments

Android L preview: Battery and power management


Man my Nexus 7 is gonna feel like a whole new device after getting Android L but I still don't like the white settings

Posted via Android Central App on Google Nexus 7 2013

+1 totally agree. it'll only be worse for amoled displays (like mine) that turn off black pixels. android is looking more and more polished!

Posted via One M8

Ars has done work and in their synthetic web page loading test a N5 lasted 36% longer.

On a practical sense we won't really see many gains from the new battery stuff in L until apps are updated to take advantage of the things like scheduling. Remember that this developer preview HSAs been in people's hands for a week. It'll take some time.

Posted via Android Central App

Intelligent response. I hate it when people don't see catastrophic improvements and immediately dismiss any improvements that might be present.

Doesn't mean we shouldn't see them.

My SoT doubled my first day with L (sounds crazy, I know); 4.5 hours SoT with like 10 hours of usage on the N5. That's with all my apps installed.

Really? My battery life has been stellar on L. The first day or two, it was average, but once everything was setup and settled, I immediately noticed longer battery life. I wish I had taken a screenshot, and it's fine if nobody believes me, (I know.."Screenshot or it didn't happen ") but yesterday, at 30% battery left, I looked at the screen on time in the battery usage menu, and it was at 6 hours 23 mins... Once again, that's still with 30% remaining.
Unfortunately, I was leaving for the day and I wanted a fully charged tablet to bring with me, (Aahhh OCD!!!) so I never got to see this through to the end; but I'm quite confident I'd have reached 8 hours SOT.
I have not modified anything in any way. These results are NOT with the power save setting on either. That setting actually works very well too, when needed. I have the brightness adjuster set dead center. I do use Google Now with my location settings using "Battery Saving" mode, since I find no benefit to "High accuracy" mode on a WiFi tablet. I also keep "Okay Google" Hotword Detection off on my tablets.
Early results are promising--to me.

You gotta remember none of the apps your are using are updated to run with L, so none of these battery saving measures are baked in yet. Also this is a preview and not final. I wouldn't read into any performance upgrades or downgrades at this point.

Yeeaah.. I'm not exactly new at this stuff, friend.. ;-)
Yes--this is a preview, and all the applications aren't updated to the same design language, however, Android L absolutely *does* make other changes to the system/services/management...It's not just a visual preview obviously.
I wouldn't read anything into a small increase or decrease on battery; however, I know how my tablet is, an it's handling battery and CPU a bit more efficiently (incidentally, people seem to report lower benchmarks as well). The only thing about it that has changed is the version of Android.
I expect things with battery life will be even better at time of release, once developers have integrated all the principles discussed in this article.
So, to conclude: I was making a statement about battery life being better...but just in general, and not really as a result of the specific changes mentioned in this article.

If this works anywhere near as advertised it will likely become the single most important part of L.

Posted via Android Central App

To my surprise this is probably the features I'm most anticipating for my S3 since the battery life is pretty shitty.

Posted from my de-TouchWized Samsung Galaxy S3 running SlimKat 4.4.2

I'm pretty sure I'll get my Android L custom ROM before whatever bloated up version you get on your phone. Unless of course you use a custom ROM too then we're on the same page here.

Posted from my de-TouchWized Samsung Galaxy S3 running SlimKat 4.4.2

While I agree it is kinda unlikely, Samsung supports their phones much longer than most have in the past (The others are getting better) so it is not out of the realm of possibility. VERY unlikely, but slightly possible.

True, if its one thing Samsung does right its actually update their phones. Unless Verizon or especially At&t have a say in it.

Posted via Android Central App

About its prediction of the battery drain, shouldn't the graph look a bit different?
I thought that battery draining is never linear (including charging).
I don't remember the exact shape (nor its name in English) though.

I know right, it's crazy to think that phones like the G2 and m8 battery will get even better with L the batteries on these 2 phones give me no reason to complain but that would be just amazing.

Posted via Android Central App

So can you set it to display battery percent in the notification bar instead of just the battery graphic yet? That's really all I want :(

Nope. This simple addition is too difficult for them to add. Of course, some people would rather you add a crappy 3rd party app to do that. Most OEMs add it, don't know why Google can't.

Posted via Android Central App

only on Super AMOLED displays. on LCD it doesn't matter. And the irony is the only company really doing SAMOLED's in any scale right now is Samsung.....and they've been changing the settings screen to a white background in touchwiz for years already anyway.

It's been quite a while tho, or was the One S AMOLED? That's still a couple years old tho... Moto X was way more recent. It's understandable since Samsung controls AMOLED supply for the most part.

After the T-Mobile knock on update, my battery has already improved by 30 percent. I can't wait to see how much longer it lasts after the project L update in the fall.

Posted via Android Central App

I wish MMS would work on android L I had to go back to kit Kat. That is the only issue that mattered to me. Is any one else having it or has fixed it?

Posted from my bathroom in the basement.....

I used gravity box to change the navigation bar to L and I must say I didn't like it at first but now I love it. Didn't take long for me to get use to it. Love the upset to Google search. Now I can say OK Google any where

Posted via Android Central App

All this HUB BUB stock android poor battery life mess filled with Android L promises is truly comical.

Thank God we users of Samsung handsets don't have to worry about this serious mumbo jumbo bull or worry about unfounded promises.

Everyone knows stock and handsets/Nexus products have been '' THE WORST'' battery draining poor quality camera products on the market since it's inception.

The android L will only make the industry leading Galaxy Note products even more better where it matters most battery life.

Samsung handles battery life excellent actually the BEST out of any manufacturer especially their products something GOOGLE/ANDROID/Nexus can learn so much about

I'm laughing at all these silly Android L promises everyone knows GOOGLE never delivers on solid promises

From my Galaxy Note 3 via Android Central App

OMG! Its RY! I haven't read one of your blathering posts about Samsung in quite some time! How ya been?

Posted via Android Central App using an LG G2.

Agreed. HTC and LG have done some great battery improvements as well. While on the other hand, Google just sits on their asses and expects the whole world to fall in love with "stock" Android. Google, you need to get your shit together. This is pathetic.

Your Samsung keyboard is pathetic considering the amount of typos and huge grammar errors in your comment.

Posted via Android Central App on Google Nexus 7 2013

Samsung sucks. Touchwiz sucks. It is slow and laggy. HTC is a million percent better as are Sony and LG.
Posted HTC One M8 via Android Central App

Hi, does anyone know if the L preview will be updated OTA?
I'm half thinking of flashing it, but don't want to repeat the process too much, I have my phone set up nicely how I want it!

Off topic, but I like the couple of 3 features Nova has added recently and looking forward to more.

Posted via Nexus 5 with SwiftKey