The Bediening is simply explained and you can actually do not do much wrong.
If the batteries are fully charged - appears a green LED and the charging process is terminated automatically.
The batteries will not be discharged again and also not damaged.
I use them for my game consoles (Wii and Xbox 360) and keep them usually at least 14 days to 4 weeks.
In addition, you can load the device also other batteries format AA or AAA.
Conclusion: BUY