Power, communication, and files

May 2, 2010

Processor power increases exponentially. Hard drive storage increases exponentially. And the energy density in batteries? Decidedly not exponential. Lithium ion batteries are thought to be nearing their technical limits, and alternatives are still probably a few years away.

I thought about this the other day when I was working at my local coffee shop. On the table in front of me I had both my fancy smartphone and my ancient MP3 player, which is what I was listening to. Because, frankly, I don’t trust my phone to have enough juice to make it through the day if I use it for frivolous things like playing Plants vs Zombies. Or listening to music.

Streaming music over the 3G network, is incredibly energy-intensive – like talking on the phone constantly. Rhapsody and Spotify have figured this out, unsurprisingly, and their iPhone apps enable you to download playlists of music to your phone over WiFi. (With an average speed of 22 Mbit/s for an 802.11g network, you can download a 5 min song at a bitrate of 128 kbit/s in just a couple of seconds, so you don’t need to spend long in a hotspot.) But having a bunch of playlists on tap is still pretty far from true streaming music.

Given a constant energy density, of course, one option is just to make the battery bigger. And my coder friends tell me that clever programming can help a lot with battery life. But for smartphones, we really just need much better power sources before the promise of whatever you want to listen to, whenever you want it, wherever you are, can become a reality. Dear materials scientists and electrical engineers, please get right on that, will you?

Thanks to Mark Chang for some technical background to this post; any misapprehensions are entirely my fault, not his.

Image: New Battery Generations, from the Argonne National Laboratory, posted here under its Creative Commons license. How freaking cool is that?


  1. Yeah they really need to step up on this battery power thing. That, and freaking BANDWIDTH.

  2. while i completely agree with the need for bigger and more energy dense battery, i completely disagree with your conclusion that jukebox in the sky isnt areality yet.

    i subscribe to Zunepass on my KIN. Using that, i routinely listen to several hours of pretty high quality bitrate streaming music each day. whatever strikes my fancy that morning, i have in about 5 seconds – and zune has millions of tracks. (and yes we can also download the track on the go for better playback)

    KIN delivers on the jukebox in the sky – at least for my sbstantial 2 hour commute each day, and in doing so removes the need to own music, sync your mp3 player to your computer, or other hassles.

    i recommend you check it out 🙂

    -from my KIN

    • Thanks, Michael. (and a disclosure statement for people who don’t know you: Michael works for Microsoft and is one of the developers of the KIN)

      It sounds like you are doing what I described for Spotify and Rhapsody – downloading playlists of songs over wifi, and then augmenting as needed over the 3G network (let me know if that’s incorrect). My point is that we don’t currently have enough battery life (energy density) in phones to do all that on the fly.

    • I think that for musicholics like debbie, the all-day cloud jukebox is still out of reach. For shorter bursts, it can definitely be done.

      • So first, I apologize for forgetting my disclosure – Debbie is correct, I am an engineer on KIN. These statements represent my personal opinions and not the opinion of Microsoft.

        So everything I wrote prior was actually referring to true streaming over 3G.

        We have the further option of allowing you to download to store locally anything you’re listening too over 3G or wifi, but I rarely use that feature becasee 3G streaming is so good.

        Mark is correct though – my music consumption on the go never exceeds 2 hours a day – which the KIN handles perfectly. For all day streaming sessions, we’re not there yet.

  3. Thank you both for the clarification. And thanks so much for adding to the discussion!

    Michael, do you know offhand what bitrate the streaming audio uses?

  4. […] posts to get you started: How artists hide from Google. Streaming music needs better batteries. Payola and self-fulfilling prophecies. Thinking about […]

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