The other reviews are contradictory in the following point partially, perhaps there are different versions, but when my cable a small red LED light while in the USB connector. At the end of charging, this is becoming weaker. When it is completely out, the charging of the battery is completed and fully. Even if the USB connector appears opaque in itself, you can see the illuminated LED very clear. In my opinion, it is therefore not necessary for it to drill a hole or similar ..
When loading via the remote control, you're never sure when charging is complete, because the local LED umfärbt be lagsam from red to green to yellow. I always ask myself if this is already green or even yellow. The red LED on the USB connector is made easy, which is a clear signal for the end of the charging cycle.
The cable is about 30 cm long. Those who want to leave the helicopter loading on the table and use a USB hub or notebook, should perhaps buy a USB extension cable.