Oh oh I think that the battery ballooned because I found the DAP floating and touching the roof....
I'm joking 
Ok got the results and the battery last for 16 hours. Not exactly what I expected but not bad either. I was expecting like 20 hours or something.
I forgot to mention that 2165 out of 2255 files are either 320 kbits CBR or Alt Preset Extreme VBR MP3s. The other 90 files are 32 kbit 1 hour podcasts. Also I forgot to deactivate the Optical port so the red led was active during the test.
It seems that with different headphones you get different results because the battery last a little bit longer when using the Senn PX-200 instead of the Shure E4.
Something weird is that the DAP keep working for about 20 minutes even when the battery indicator was at 0%.
Well there you got it so far so good. Now you know that you can leave the factory molex connector and just swap the cables.
