When you have it plugged into the Nexto, does it charge at the same time as the internal battery? So when the red light turns off indicating a full charge, are BOTH the internal and external battery completely charged?
Is the external rechargable battery pack a Li-ion or NiMH battery pack?
When you connect Nexto into AC adapter, internal battery is charged first and then external battery. And, when red light turn off, internal and external battery is fully charged.
the external battery is Li-Ion.