Triflex charging state indicator:

The battery charging state is displayed on the front of the PowerUnit.
Duoflex charging state indicator:

The battery charging state is displayed on the top of the PowerUnit.
Battery charging state indicator (while charging):
Duoflex HX1:
Lowest capacity: left indicator flashes.
Increasing charging capacity: left indicator lights up; middle indicator flashes.
Further increase in charging capacity: left and middle indicators light up; right indicator flashes.
Charging capacity approx. 91–99 %: left, middle and right indicators light up.
100 %: indicator switches off.
Battery charging state indicator (while in use):
Triflex HX2:
100–70 %: top, middle and bottom lights are lit up.
69–35 %: middle and bottom lights are lit up.
34–11 %: bottom light is lit up.
10–0 %: bottom light flashes slowly.
Duoflex HX1:
Maximum charging capacity: all indicators light up.
Decreasing charging capacity: two indicators light up.
Charging capacity decreasing further: one indicator lights up.
Minimum charging capacity: one indicator flashes.