02-20-2009 06:59 AM
Taken from my battery test thread: http://forums.sandisk.com/sansa/board/message?boar
Being curious how long my Clip's battery lasts while playing certain bitrate songs, I started conducting tests. Testing details are at the end of this post.
The results: I will update as I complete more tests. Test Results in Hours Minutes Seconds HH:MMS
Charging Silver Clip 4GR1:
Charging from Desktop PC USB: Test1: 03:39:00 Test2: 03:45:00
Charging from AC adapter: Test1: 02:20:00 Test2:
Charging Black Clip 8GR2:
Do headphones make a significant impact on battery life?
Black 8GR2 playing Flac Level8 encoded album at 1/2 Volume
Standard Sansa Earphones xx:xx:xx
Playing Time - Comparing the Silver 4GR1 vs.. Black 8GR2: 1/4 Volume
Silver Flac Lvl8 : 09:02:00 * Silver wins lasting an hour longer than the Black 8GR2 *
Silver Flac Lvl0 : 08:59:00 * Silver wins lasting an hour longer than the Black 8GR2 *
Silver Ogg q8.5 ~256k : * Going to retest - Silver died while I was away *
Silver Ogg q5 ~151k : 10:15:00
Silver MP3 v0 ~252k VBR : 15:07:00 * Appears ARM clocking to be same as that of v2 *
Silver MP3 v2 ~190k VBR : 15:09:00 * Appears ARM clocking to be same as that of v0 *
Silver MP3 v6 ~128k VBR : 17:40:00
Playing Time - Comparing Various Encoding Options:
Silver 4GR1: Standard Sansa Earphones
Flac Level8 : 1/2 Vol = 09:02:00 1/4 Vol = 09:15:00
Ogg q5 ~151k VBR : 1/2 Vol = 10:03:00 1/4 Vol = 10:15:00
MP3 v6 ~128k VBR : 1/4 Vol = 17:40:00
Black 8GR2: Skull Candy FMJ's
Flac Level8 : 1/2 Vol = 07:46:00
Black 8GR2: Standard Sansa Earphones
Ogg q5 ~151k VBR : 1/4 Vol = 12:12:00
MP3 v6 ~128k VBR : 1/4 Vol = 20:47:00
MP3 v2 ~190k VBR : 1/4 Vol = 17:18:00
Playing time vs.. Volume level?
Black 8GR2 - Flac Level 8 encode
1/2 Vol - Sennheiser HD-595 07:40:00
What effects the battery life of the Sansa Clip?
Processor: Arm CPU clock speed
Silver 4 gig Revision 1 Clip Firmware version: 01.01.30a
Music used for test:
Codecs used for encoding:
The album was played endlessly on repeat until the battery ran out of juice and the player died (battery low). Test Results in Hours Minutes Seconds HH:MMS. Seconds were ignored, not significant. In any individual data sampling test there is uncertainty. Don't be surprised at the variation. You can't calculate to the minute exactly how long your battery will last.
Observation on battery power percentage measurement:
The Power% measures in increments. 0,7,14,21,28,35,42,50,57,65,71,78,85,92,100
Volume Control Settings used for this test:
I don't experience any issues with battery leakage, other than once in awhile I may leave it playing when I am wearing it, or after I unplug it from the power. The clips battery lasts an amazing long time. I stick with higher bit rate VBR MP3's encoded with Lame's codec. v0 or v2 settings and get around 15 hours of use ( I have never ran out of juice , as I usually plug it back in after a long day).
I may repeat a few tests in 6 months to see if the battery degrades over time. They say at 500 charges you will still get 80% battery capacity, so with normal use I expect the clip lasts a decent time. At least long enough for the next cheap mp3 player to be released with more memory.
02-20-2009 08:55 AM
>> Silver wins lasting an hour longer than the Black 8GR2 *
I think the problem is that there is a quality control issue in the manufacturing of the batteries. You could compare several Clips of the same capacities and colors, and still get wildly different results between them. i.e. there are some 2GB red Clips that play 11 hours...and some that will play for 15 hours...and some that lose charge when not even playing.
The batteries are the weak links in the Clips. You just happen to be seeing the difference between two Clips of different capacities and different colors...but you'd still likely experience those differences even if you were testing two identical Clips. They all have the same battery...and it's just the luck of the draw as to whether any Clip has a good, mediocre or bad battery.
02-20-2009 09:13 AM
Yes, I agree there is battery capacity variations. They are probably all within an acceptable power range.
What I don't understand about the tests is, the Rev 2 black clip was consistantly averaging longer play times for both ogg and mp3 formatted files. I did many and the variance was consistant with these two formats. But on the Flac encoded files, it was reversed and an unexpected result. This makes me suspect that the firmware on the Rev 1 clips are clocked at a slower rate for Flac encoding than the Rev 2 clips. It's just suspect, I hope someone at sansa notices this, and checks.
02-21-2009 08:24 AM
This is wonderful. Thank you very much for all the hard work. You MUST be an engineer. Can't wait for the next round of results. Hope it will include tests at full volume, since that is where I play mine (bad ears). Ratio of charge time to play time seems impressive. If only they could get an electric car to run that well.
I am confused about one thing. I can't find an 8GB clip on the Sansa website.
02-21-2009 08:49 AM
The 8GB clip exists....but you can find it cheaper than the price you will see there.
Clip Zip 4GB+16GB, e280, Fuze+ 16GB <--All rockboxed. Cowon D2+ 16GB+32GB, Sony NWZ S639
Nexus 7 32GB, Samsung Galaxy Tab 7.0 Plus 16GB, LG Optimus G Pro 32GB+32GB