In just under four hours of charging time for an empty battery pack, the external charging possibility seems to me a "must" to be. Sony should mitliefern even the same. Have the same time the 12 volt option tested on my solar system. As long as the battery is charging, the LED is red and once the battery is full, it will turn green. The charger is small and "cute" and can also be connected to the mains voltage of 230 volts (see other customer reviews). The value for money seems to be unbeatable.
