1. Deron Baker's Avatar
    Smart phones are an interesting bunch when it comes to battery life. So much is debated and posted on web pages about the subject; it has become a primary concern for potential buyers. It is rather difficult to get a good description of battery life when perusing message boards because users expectations are not the same. What is one mans great battery life is another mans reason to return the phone and get another one.

    In an attempt to provide some sort of objective, verifiable evidence of battery life for the new Droid Razr, I conducted a series of (somewhat) controlled experiments. To help bring a better perspective, I also ran the experiments with my previous phone, the Droid X.

    What can be gleaned from all this? I think there are two important conclusions. First, it can give potential buyers an idea of how the Razr compares to a previous generation smartphone. The Droid X is a good comparison since both phones have 4.3 inch screens and are marketed to the same type of user. In other words, does the more powerful phone sacrifice battery life or does its larger battery make up for this? The second conclusion is that Droid Razr owners may learn how to better manage battery life, or at least understand the tradeoffs that come with using the mighty 4g network.

    I start by summarizing the results so you can get the quick and dirty on it. In a subsequent post I will discuss my methods. The term PPPH = Percentage Points per Hour. PPPH is the average percentage points of battery capacity you can expect to lose when doing a particular activity for one hour. This happens in a (mostly) linear fashion, although battery capacity drains somewhat faster once the percentage drops below 30%. For example, if watching Netflix via 4g LTE network drains about 35 PPPH, just subtract 35 from your starting battery percent to get the percent battery after an hour of use. So if you start at 95% battery capacity, an hour of watching Netflix via 4g will drain your battery down to 60% (95 minus 35). Or if you start watching Netflix via 4g with a battery capacity of 50%, an hour later you will be at 15% battery capacity (50 minus 35). Or if you start at 90% battery and watch for 2 hours, your battery will then be 20% (95 minus 35 x 2). Another way to use this information is to divide 100 by the PPPH to obtain the approximate time you can do an activity, starting from a full battery. So, at a 35 PPPH battery drain, starting with a full battery you can watch about 2.85 hrs, or 2 hr 50 min of Netflix via 4g. (I know, it sucks.)

    In my subsequent post I will provide a link which shows the specific settings I used for each experiment. In general, all tests were done with Bluetooth off, screen brightness 50% or screen off (depending on the experiment), speakers/headphones volume 50%, landscape view for videos.

    Droid X data

    Activity---------------------Avg PPPH---How long on full battery

    Netflix Video 3G--------------40---------2 hr 30 min
    Angry Birds------------------35---------2 hr 50 min
    Web/Email Browsing 3G-------28---------3 hr 30 min
    GPS Navigation 3G-----------25---------4 hr
    YouTube Video WiFi----------20---------5 hr
    Phone Call-------------------10---------10 hr
    Streaming Music 3G----------7----------14 hr


    Droid Razr data

    Activity---------------------Avg PPPH----How long on full battery


    Angry Birds------------------40----------2 hr 30 min
    GPS Navigation 4G-----------35----------2 hr 50 min
    Netflix 4G--------------------35----------2 hr 50 min
    Youtube 4G------------------35----------2 hr 50 min
    Web/Email Browsing 4G-------33----------3 hr
    Netflix 3G--------------------32----------3 hr
    GPS Navigation 3G-----------28----------3 hr 30 min
    Web/Email Browsing 3G-------27----------3 hr 40 min
    Netflix WiFi------------------17----------5 hr 45 min
    Youtube WiFi----------------17----------5 hr 45 min
    Phone Calls------------------9-----------11 hr
    Streaming Music 3G----------7.5---------13 hr
    Passive Battery drain---------0.5---------200 hours


    Side by Side Comparison
    The numbers are the PPPH drained for each activity. (Remember that Droid X does not have 4g.)

    Activity---------------Droid X-----Droid Razr

    Netflix 3G--------------40---------32
    Angry Birds------------35---------40
    Wed/Email 3G----------28---------27
    GPS Navigation 3G-----25---------28
    YouTube WiFi----------20---------17
    Phone Call-------------10---------9
    Streaming Music 3G----7----------7.5
    12-04-2011 09:40 PM
  2. Deron Baker's Avatar
    Caveat: I understand that no one charges their phone to full capacity and then does one activity until the battery is dead. Also, those numbers might over-estimate the actual time you can perform a given activity from a full charge since the battery drains slightly faster once capacity drops below 30%. Instead, it is better to focus on comparing the PPPH numbers.

    The point of doing these experiments is to get a comparison of how battery is drained by doing various activities and to see how Droid Razr compares to Droid X. In actuality, most users will vary their use from day to day and will only perform these activities for short periods at a time. Still, getting an objective measurement of battery drain can give a clearer picture of battery life.

    A couple of conclusions can be drawn from this:

    1. Droid Razr and Droid X have very similar battery lives, with Droid Razr having a slight advantage overall. This rule only holds true for WiFi and 3G, since Droid X lacks a 4G radio. (Using 4g on Droid Razr will drain the battery faster than 3g on Droid X, albeit youll get faster data speeds. The one exception is with Netflix. Watching Netflix via 4g on Razr is actually more battery efficient than watching Netflix via 3g on Droid X.)

    2. On Droid Razr, when using a particular app, battery drain is 4G > 3G > WiFi.
    On average, 4G drains battery about 10 20% faster than 3G, doing the same activity. (This is not to be confused with 10 to 20 percentage points.)
    On average, 4G drains battery about twice as fast as WiFi when watching streaming video (the most data-intense activity you can do on a phone.)

    3. There is no good reason to use the 4g network for GPS/Navigation in your car. Use 3g only. Three reasons for this: 4g drains battery about 25% faster than 3g using Navigation. Secondly, 3g speed is fast enough to update Google maps on the fly. Lastly, 4g coverage is limited geographically while 3g is widespread. While driving it is possible to lose 4g coverage, causing the phone to temporarily stall while switching to the 3g radio. Imagine this happening at a crucial turning point in your navigation route.

    4. Using the Smart Actions app to shut off cellular data (3g/4g), WiFi, and GPS when the screen is turned off causes battery to drain at an extremely slow pace. And this still leaves the phone on standby to receive phone calls and texts.
    12-04-2011 09:42 PM
  3. Deron Baker's Avatar
    To obtain the data, I ran a series of (somewhat) controlled experiments. Running the tests multiple times, I then averaged the results. I also held certain settings, such as screen brightness, the same throughout the tests to minimize variables.

    Basically, I ran each test by noting the start time and start battery capacity (as reported by the Battery Circle widget in exact, not rounded, percentages). I ran the experiments according to my settings and methods and then noted the end time and end battery capacity. I then calculated the time elapsed (delta time) in hours for each run as well as the starting battery percentage minus the ending battery percentage (delta percentage points). Then I divided delta percentage points by delta time to obtain the Percentage Points per Hour (PPPH) drained. An example will make it clear:

    For my Netflix 4g test, I did the following:
    - Set screen brightness to 50%, no screen timeout, headphones volume 50%. Plugged in headphones. Set the Network Mode in settings to CDMA/LTE. Confirmed I had the 4g symbol on the phone.
    - Wrote down the start time and start battery percentage.
    - Opened up the Netflix app and went into my instant que.
    - Started playing a movie.
    - I either watched the movie or let the phone sit near me so I could verify it was playing.
    - Periodically I would listen to headphones to ensure audio was still going. Periodically I would tap the screen to show the notifications bar to ensure the phone was still using the 4g LTE network. Periodically I would laugh at the absurdity of the Jersey Shore episode I was streaming. (I was not able to calculate the number of brain cells lost watching that show. Perhaps a future experiment.)
    - After a while, I would then stop the movie and hit the home button to exit the app. I would then write down the end time and end battery percentage.
    - I would repeat this process several times at varying lengths and varying starting battery percentages.
    - For example, in my first run I started at 1043 (military time) with starting battery percentage 96%. The end time was 1220 and end battery 41%. The delta time was 1.62 hours, the amount of time from 10:43 am till 12:20 pm. This is 1 hour and 37 minutes. I divide 37 minutes by 60 minutes to get the time in decimal form. So 1 hr 37 min becomes 1.62 hrs. Now I take the start battery 96% and subtract 41% to get delta percentage points of 55 percentage points. Now divide 55 by 1.62 to get 34 PPPH. In other words, if it took 1.62 hours to drain the battery from 96% down to 41% that is the same as 34 percentage points per hour drained.

    If anyone is interested in seeing the raw data: https://docs.google.com/document/d/1...QUCAoxHOw/edit

    Let me highlight my settings:
    - Screen brightness 50% on all tests that had the screen on
    - Screen off for phone calls and streaming music.
    - Speakers or headphones volume around 50%.
    - Music stream test was done with Google music cloud player.
    - For the phone calls test, I used my GFs land line to call my cell phone. I played continuous music (the new Megadeth album) through the land line cradle to create a constant source of sound. I checked on my cell phone periodically to ensure it was still connected.
    - For passive battery drain, I used the Smart Action app to turn off cellular data, WiFi, and GPS when the screen was off. I wrote down battery percentage and time before I went to bed and then shut the screen off. I did not touch the phone at all until I got up the next morning. Then I turned on the screen and noted the time and battery percentage.
    milkshed27 likes this.
    12-04-2011 09:45 PM
  4. TrendyProfessional1's Avatar
    Thank u very much.....
    12-05-2011 10:33 AM
  5. Deron Baker's Avatar
    Welcome. Now if someone with an HTC Rezound would run a few of these tests for comparison, I would be much appreciative. That's what we really need: a head to head with the Razr, Rezound, and Galaxy Nexus.

    Sent from my DROID RAZR using Tapatalk
    12-06-2011 09:30 AM
  6. GMasonDragonDad's Avatar
    Deleted
    09-20-2013 11:51 PM
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