My CZ is a little over a year old now and I noticed that I don’t get the battery life I did a year ago. I thought it was due to the 320k VBR MP3 files I normally play, compared to the 128k CBR file I used for battery life testing a year ago. So, I tested it again with a 128k CBR file, looping the song and playing my headphones (Sennheiser/Adidas around-the-neck phones) at moderate volume (2 ticks above minimum). I’m running the stock, lastest Sandisk firmware.
In my tests last year, I got 17 hrs. of battery life, a pleasant surprise since Sandisk claims 15 hrs with 128k MP3 files. This time, I didn’t even get to 12 hrs under similar conditions. I thought, ‘great, the warranty just expired and the battery is already going’. I then realized the file was on my SD card (Sandisk 32GB, class 4), not the internal memory.
I tried my test again, this time playing a 128k file off the main memory and removed the SD card. Lo and behold, I get the 17 hrs. as in last year’s test. The battery isn’t going on me; the SD card uses up a lot more current than I expected.
If anyone has the time, I’d love to see if these results can be repeated. I won’t give up the 32G card but was surprised it knocked that much life off the battery. I’m also guessing that the battery life per charge goes down when using the external card, not when it’s just plugged in.