[Reimar]

The Batteries are Lithium Polymer, each contains 3.7 VI wrote in a other thread that those batteries are sensitive to charger. For my own I use the following config: 1. a power supply AC 230 V to DC 12 V; 2. connected to that power supply a RC Model charger DC 12 V 1-3 Cell Microprocessor Charger and charging power 250mA to 2000mA, it's a Prolux 3834

Using that to charge the Batteries while set to 2 Cell, brings me more than 4 h time of using.