Nikon DSLR battery project, used equipment

Here is a brief view, to selected equipment - what I use my LiPo battery project:

Microcontrolled charger (Robitronic LD15z)
Orion LiPo 3S 11.1V 2100mAh battery
Orion LiPo 4S 14.8V 6400mAh battery

Drawback in the first battery, is the output voltage range. In full charge (3*4.2V=12.6V) it can feed Nikon D200 without any voltage converter. When battery is discharged, voltage drops below the specified level. It remains to be seen, whether it affects to camera operation.... This battery equals to capacity, usually found in pro-DSLR's, like D3/D4.

The second one, provides approcimately three times capacity than first one (3S 2100mAh version). Output voltage in the 4S version, is too high to  be connected directly to D200. Fully charged battery provides approximately 16.8V. Nikon own power supply EH-6 provides specified 13.5V output voltage. Connecting battery directly, might blow up my camera, and I do not want it to happen. So in first phase of test, I propably will make diode connection is series. That will drop voltage approximately 3V (5*0.6V). Then output voltage would vary somewhere in range of 11.8...13.8V.

Microcontroller charger

Orion 3S LiPo battery

Orion 4S LiPo battery