Hey Nikloai,
No, nothing unusual there. When I ship the the DS-1300, the way I have it configured, it will ONLY display the battery status via the case-mounted RED LED. To get the full story (and I'm still not sure I explained it very well), you need to check out this BLOG entry.
The long story short is that if you want to enable the main LEDs to show you the battery status (for example, for a helmet mount application), then you have to go through the menu programming and:
1) Restore the "default" state of the firmware
2) Re-set the temperature trip limit to 60 deg C (up from the default of 50, which is what is used for the taillight).
Now the headlight will act just like the taillight with regard to flashing out the battery status with the main LEDs. The caveat is that after performing the factory reset function, the headlight will be in "multi-mode" (i.e. all 5 power levels available in steady mode). As soon as you switch it back to "three-mode" (the preferred headlight run-mode), then you'll lose the main LED status indication. No matter the particular mode or state of the firmware, however, the case-mounted LED on the headlight will always indicate battery status as documented.
This quirk is the result of a single line of code that was left out of menu #5 and the above procedure is really more of a "work-around," so that helmet users can at least have the option of seeing the battery status indicated by the appropriate flashing of the main LEDs.
Charge the battery whenever you like, no need to wait till it's discharged. I tried to set the 50% indication to be fairly accurate on a "timeline" basis for any given run mode. In other words, if the light would run in flash mode 1 for 10 hours, then when the status LED first turns on and stays solid, indicating 50% capacity remaining, you would expect roughly 5 hours of run time remaining. As soon as you change power levels, however, you essentially switch to a different "timeline" so a lot of the battery status usefulness will come as you get familiar with how the various power levels behave.
Also be aware that it is totally normal to feel a little warmth in the PCB inside (under the skin) of the battery pack as it's nearing the end of charge and even for a while after it's removed from the charger due to the self-balancing function of the PCB. This may diminish with time as the cells may become more precisely balanced.