Short answer: Yes, it's safe.

Longer answer: The eDGe's battery is Lithium-ion polymer type, which is standard for portable devices these days. Such batteries are NOT prone to memory, contrary to popular belief. Incidentally, you also don't need to charge them for 8 hours the first time.

For more info, see URL below:

http://kipre.wordpress.com/2009/03/2...mer-batteries/