''Hint:
For the DPSI Micro - DualBat, two identical batteries must be used, i.e. same
type (NiCad/NiMH or LiPo) and same cell number. The capacity may vary – even
if this does not make sense.''

Another quote from the manual !
It has completely separate pathways for each batt,,.
It will take from the higher voltage source at all times, therefore normally maintaining an equal voltage batt 1 to batt 2.
It has separate and combined low voltage warnings.
The manual is a German to English translation - some quirky phrases result.

Brian