[HWTest]

The "Charger doctor" arrived. Now I'm charging the X3 (forced shutdown charging) and the "doctor" displays 4.97V 0.85A on the 2.1A charger.
I'm starting to think its not a problem of the charger but of the X3, because the second thing that troubles me is, I'm not getting the advertised 10 hours of battery life.
I get only 6 hours of playback time. Tested on FW 2.1, flac 44.1/16, low gain, volume 30, Sennheiser CX-300 connected, no fiddling around with the player during the test, screen was only on on the start of the test.
Is this reason enough to RMA the X3?

 

[giorgio09]

  The "Charger doctor" arrived. Now I'm charging the X3 (forced shutdown charging) and the "doctor" displays 4.97V 0.85A on the 2.1A charger.
I'm starting to think its not a problem of the charger but of the X3, because the second thing that troubles me is, I'm not getting the advertised 10 hours of battery life.
I get only 6 hours of playback time. Tested on FW 2.1, flac 44.1/16, low gain, volume 30, Sennheiser CX-300 connected, no fiddling around with the player during the test, screen was only on on the start of the test.
Is this reason enough to RMA the X3?

 
Yes
Something is wrong with yours X3.
My X3 battery , FW 3.0, high gain, volume 60  with Flac lasts almost 8 hours and 50 min.

 

[HWTest]

   
Yes
Something is wrong with yours X3.
My X3 battery , FW 3.0, high gain, volume 60  with Flac lasts almost 8 hours and 50 min.

Thank you for the information.
 
Freshly charged the X3, so I'm going to test it again with FW 3.0 and report back.

 

[HWTest]

I did some playtime tests and here are the results:
 
10:17  16/44.1 FLAC (level 5)
09:11  24/96 FLAC (level 5)
 
FW 3.0, low gain, volume 60, Sennheiser CX-300 connected
The results seem to be OK.
 
But now the strange part.
First I was charging using the new 2.1A charger, charging current 0.82A (showed by the charging doctor), took little less than 4 hours to full charge.
For the second cycle I've used the older 2.1A charger, charging current 0.82A, took little less than 4 hours to full charge - this never happened before with this charger, it always took over 6 hours!
For the third cycle I've used again the older 2.1A charger, charging current 0.41A, took took 6,5 hours to full charge - why (only 0.41A)?
The charging current goes continually down, in the last third (guessed) of the charging process, to 0.01A in the end - next time I'll take notes, to be more exact.
 
Another thing - the X3 has a 3000mAh battery, if I'm generous 4x0,82 = 3.280Ah = 3280mAh, knowing there is a charging factor 1.4-1.6 (you have to deliver more charge, by that factor to fully charge) and taking the lowest, I get 2343mAh. And that calculation is very optimistic.
One explanation is, the charge doctor is very inaccurate or something is wrong with my X3.

 

[HWTest]

Some news.
 
The charge doctor is pretty accurate - verified the readings with a quality DMM (Metex).
I also verified that both 2.1A chargers are capable of delivering 2A without the voltage breaking down.
 
This time I took notes during the charge process and here are the results.
2370mAh - charge delivered through the entire charging process.
Using the charging factor 1.4 this gives a approximately 1700mAh battery!
I don't think it is normal, that the capacity of the battery drops down to 57%, after 10 months of  very light usage (about 20 charge/discharge cycles).
 
I noticed an interesting thing - in the first couple of seconds, after the start of the charging process, the current fluctuates. Maybe this is the time, the charging circuit determines how much current it can draw. And I (almost) always in this time pressed and hold the power button of the X3, to put in the forced shutdown charging mode, which maybe somehow disturbs the charging circuit, when determining the charging current?

 

[tjw321]

  ...
I don't think it is normal, that the capacity of the battery drops down to 57%, after 10 months of  very light usage (about 20 charge/discharge cycles).
...

But you just got 10 hours of FLAC playback, so I don't think your battery has really dropped down to 57%.

 

[HWTest]

  But you just got 10 hours of FLAC playback, so I don't think your battery has really dropped down to 57%.

 
I agree.
 
But I got only 6 hours with firmware 2.1 when my X3 was new.
 
That's why I started this thread http://www.head-fi.org/t/729179/how-long-does-the-battery-in-your-x3-last hoping that someone will repeat my tests and I have some numbers to compare

 

[HWTest]

I did make a graph of the current during charging.
Ignore the values, because the used DMM has only 20A, 200mA and 2mA ranges and there is a big measuring error, measuring 500mA in the 20A range.
The shape is important.
The slope on 16' is caused by switching the X3 to forced shutdown charging.
 

 
 
 
Zoomed to the start of the charging process. It seems that in the first 20-25 seconds it starts charging with a lower current, then determining somehow, if it can draw more and switching to higher current.
Maybe my problem was trying to switch to forced shutdown charging in this phase.
 

 
 
Zoomed so, that also the point of switching to forced shutdown charging is visible.

 
 
 
On another note - I could measure the capacity of the battery precisely. I have the equipment. But that presumed the disassembly of the X3 to disconnect the battery for proper measurement, which would void my warranty ...