I have the same problem with SGS2. Kills my battery in hours. I have to charge my phone 2 or 3 times per day now if I listen music. My old HTC Wildfire lasted much longer with same usage. I hope spotify does something to this problem. Otherwise I will stop using spotify for a while.
EDIT: I think my old wildfire used something like 20-50% CPU when using spotify. I might remember it wrong. On SGS2 spotify uses less than 0,5% when listening local music and 6-17% when listening offline-playlists.
Update: For some reason Spotify seems to heat up my phone when screen is off. Phone is cold when screen is on and I am listening music but starts warming when I turn screen off. Battery doesn't get hot, only upper part of the phone. It is just like the prosessor is running 100% load or something. Really weird. I wonder if this Spotify problem or whether this is in any way related to the suspend-bug.
I tested grooveshark. Uses about 0.5-6% CPU at the beginning of the song (10-20s) but returns to zero after a while. Keeps phone awake. UI seems quite stable. However, it is little bit confusing. Seems a little unfinished. Music wasn't very well-organized. I don't like it.
Test 1: I pooled cpufreq readings (while() do cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq; sleep 15; done) and waited about 5 minutes. Result: 200Mhz, almost constant. Then I turned the screen OFF and waited for 10 minutes until the phone began to feel hot. I checked cpufreq pools. Result 1200Mhz, constant, at least 3-4 minutes. Cpufreq returned to normal after I turned the screen ON.
Test 2: top -m 20 -d 60. I waited 5 minutes. Result: spotify cpu usage 4-17%. Then I turned the screen OFF and waited for 15 minutes until the phone began to feel hot, again. I checked the latest top output. Result: spotify cpu usage 49%. Cpu usage returned to normal after I turned the screen ON.
If I understand this correctly, this means that the spotify retains a whole cpu core for itself forcing it to run at full clock. This might be the real reason why spotify kills my battery.
I reported this to the spotify-group by email. I hope that they will do something about this problem.
I just received a reply to the original e-mail: "Please note that the Galaxy SII is not supported by Spotify yet. Having a Galaxy SII (dual core) app is something we want to do at some point but as with all development plans we don't discuss future releases. When we have something to say about a dedicated dual core app we'll be sure to let everyone know."
I suspect this has nothing to do with dual core processor. My understanding is that Android 2.3.* doesn't even have a full dual core -support (meaning that normal app sees only one core, OS two). Correct me if I am wrong... I would guess (based on my Wildfire+spotify experience) that this problem occurs with other phones too. SGS2s more powerful processor just makes things worse. Both cores run at 1200Mhz and one at full speed...
I am testing review-version (0.4.9.175). Preliminary results seem good. No heating yet.
oh no, this all sounds terribly upsetting.
i just got a GS2 today and just installed spotify, not really used it yet. if what i'm reading here is true then the phone is not yet supported by the app? that's rubbish
i've been using spotify on my HTC Desire for nearly a year now, happily paying