back to article Nokia app monitors juice

A new application from Forum Nokia allows developers, and anyone else, to see just how much power their phone is using, and compare consumption when running different applications. The app is free to download from Forum Nokia, the Nokia developer's portal, and runs on S60 3rd-Edition handsets. Our N95 averages out at around …


This topic is closed for new posts.
  1. Jasmine Strong

    You must be doing something wrong...

    ...because my N95 has plenty of RAM to play videos at the same time as it runs the energy monitor; not a lot of point in having one otherwise, is there?

    It uses about three watts. However, note that:

    a) the energy monitor itself burns about a third of a watt (which is an order of magnitude more than the normal quiescent power of the N95 as measured with my handy dandy milliwatt meter.

    b) running two apps at once is disproportionately hard on the battery in these devices due to the cache pollution side effects; ARM1136JF-S doesn't have that much cache, and all code segments are cacheable in SymbianOS, so the RAM interfaces will be working much harder with the energy monitor running than it would be otherwise.

    Measured figures with a meter:

    Typical power dissipation of an N95-3 playing AAC audio at 320 kbits/sec into 32 ohm headphones at maximum volume is around 300 mW with display illuminated and 200 mW with it dark, while on a rather weak UMTS HSDPA cell (-= 30 mW for GSM/Edge), Bluetooth on (probably <10 mW- was lost in the noise), WLAN off (depends on your power setting, but generally double the setting's ERP), and with no USB connected (+= 100 mW or so for the USB line drivers).

  2. John Latham

    It may be free to download...

    ...but the download fails (whining about missing metadata) unless you're registered with and logged in to Forum Nokia.


  3. John Parker
    Thumb Up


    I code etc. on phones, and just wanna say that's a great first comment :)

  4. auser

    Shouldn't this be a built-in functionality?

    Like in the case of the good old sony-ericsson-s where it's part of the hardware info, along with the battery status and temperature, the cpu temperature, the radiated power and lots of other junk... You can even get this info through the standard (serial or usb) modem interface without starting an exra application.

  5. Tim Spence

    S60 3rd-Edition

    Yes, the article is correct in that it does *run* on S60 3rd-Edition handsets, but it's next to useless as the measurements only work on Feature Pack 1 (and onwards) devices. That rules out my N80 anyway.

    Just thought I'd point it out like.

  6. MikaK

    Most accurate measurements and RTFM

    For the best power measurement accuracy, use 5 s mode and "Manual Only" screenshot trigger (in Settings). Read also Options>Help since it actually has some good information - not just typical blabla.

  7. Tom

    I dunno

    I mean, when you're running Fring or some other energy-intensive, always-on program on your phone, the battery life takes a real hit (from 3 days to "get out of my way, can't you see my phone is dying?!"). If this encourages the program makers to fine-tune their apps, or even put in an energy-save option, then it can only help.

    As for its poor interaction with other programs, they aren't going to be run in isolation anyway, so it may not make all that much difference.

  8. Anonymous Coward


    wonder how much juice is used when the battery explodes in your face?

    (pocket pc's have had this functionality for a while haven't they?)

  9. AndyB
    Jobs Halo

    does it...

    ... Work on the iphone?

  10. MikaK

    Re: It may be free to download...

    You don't need to be registered/logged on for download. John L which browser are you using? Works fine with laptop + Firefox. S60 browser download problem is .ZIP file, we will fix this asap.

  11. Stewart Atkins

    Re:You must be doing something wrong...

    pre-v20 firmware its quite easy to push it out of memory. Since the update mine has been performing a lot better memory wise, but just ran a video playing test with energy profiler, it went up to about 5w average while it was playing

  12. Werner Ruotsalainen

    nope, no iPhone

    AndyB, nope, it doesn't - it's a Symbian-only app.

  13. Werner Ruotsalainen

    real-world tests

    Some VERY thorough tests posted to... (these are cross-posts to different forums!):

    You’re welcome to comment on them.

  14. Werner Ruotsalainen


    [i]<i>“a) the energy monitor itself burns about a third of a watt (which is an order of magnitude more than the normal quiescent power of the N95 as measured with my handy dandy milliwatt meter.”</i>[/i]

    That’s quite a lot. BTW, as I’ve also explained in the article (and, for example, at ), the numeric battery life estimation results it provided were all VERY close to the results I’ve measured on my relatively (~2 months old; that is, it’s not worn-out in any way) battery with my “let’s completely deplete the battery to find out how long it lives” approach. That is, even if it indeed consumes a lot of battery, in my N95-1 v20 tests, its results have turned out to be very reliable.

    [i]<i> “Typical power dissipation of an N95-3 playing AAC audio at 320 kbits/sec into 32 ohm headphones at maximum volume is around 300 mW with display illuminated and 200 mW with it dark”</i>[/i]

    200 mW is VERY low and would result in about 18 hours of continuous playback, which is certainly not the case, not even with the v20 firmware (with AAC, the typical playback time is about 8 hour under the circumstances you’ve described).

    I’ve measured the total battery life (with the deplete-it-completely approach) and Nokia’s Profiler several times and I’m absolutely sure the battery life is 8 hours when playing back AAC / MP3 / WMA over the factory headphones at 70% volume (NOT 100% as is in your tests – that is, my setup should consume even less power than yours).

    Are you ABSOLUTELY sure your figures are OK?

    [i]<i>“while on a rather weak UMTS HSDPA cell (-= 30 mW for GSM/Edge)”</i>[/i]

    I recommend my related 3G vs. 2G measurements on both strong and weak signal. With the former, it’s “only” the average power consumption that is much higher than with 2G networks, there’re two entirely separate cases: either the base power consumption (which is exactly the same as with 2G) or the very high peaks (which, on the other hand, are way more than +30 mW). That is, is your +30 mW a time-averaged value (then, it seems to collerate with my results), or, just one in a definite time instance?

  15. Werner Ruotsalainen

    @Stewart Atkins: 5W while playing back video? Ouch!

    5W means about 50 minutes total playback... What format was it in? What did you use for playback? I've thrown several, even high-res (VGA native MP4 / DivX) video files at both RealPlayer and the current version of CorePlayer. I've never measured power consumption OVER 1 Watts with the lowest backligt level and moderate speaker volume.

    Are you sure the handset wasn't on a charger while doing the tests?

  16. kevin pownceby

    n95 battery

    I could'nt give hoot about a meter that tells you about how much power you use, what i want to know is when are nokia going to to build a battery for the n95 that lasts longer than the rubbish one that they sell with the phone now, that's what every nokia n95 user wants to know.

  17. Werner Ruotsalainen

    @kevin pownceby

    Unfortunately, you just cant expect more of a 120g, snappy (!) all-in-one device - unless you don't use its advanced features, that is. Otherwise, name any 120g 3.5G (HSDPA) device offering so much versatility and having a considerably better battery life.

    Nevertheless, the new, v20 firmware has a definitely better power management - power saving can be as high as 45%. You might want to read my above-linked article(make sur eyou follow the links to my earlier ones too), where I've explained this all.

  18. Jasmine Strong

    My figures

    My measurements were time-averaged by the (physical, not software) meter I used to take them. My N95 is an N95-3, and has slightly lower power consumption and a bigger battery than the original N95.

  19. Werner Ruotsalainen


    Thanks for the clarification.

    I still dont understand how AAC playback can only consume 200 mW - it's way lower than I've measured on the 95-1 - or, for that matter, others measured on their 95-3 using the traditional "let it continuously play back some AAC files until the device shuts down" method (that is, no software metering had taken place). After all, consuing 200 mW would result in the impossible 18 hours of playback, which is certainly not achievable, not even with the N95-3.

    In addition, many ave reported (see the benchmarks at ) that the N95-3 has slightly (about by 7%) higher (!) power consumption than the N95-1. (The figures are really worth checking out.) Any comments on this?

This topic is closed for new posts.

Other stories you might like