After connecting the battery (or after a reset by pressing the button for 30s) the SBX charger initializes the battery once. 

This is done by charging up once to the Initial charge level (see table below).

Battery PackNominal battery voltageInitial charge level (*)Nominal operation level
NiMH 6S1P (Standard)7.2V8.1V6.6V - 9.0V
Li-Ion 2S2P7.4V7.4V6.0V - 8.4V

After initial charge, device operates in nominal operating level. 

LED Indication

Initial charge is indicated by a fast blinking battery led (V4.1.0 and never)