There are tons of different threads all over the place that explains about how to properly charge and discharge lipo batteries. Long story short, you do not want to discharge lipo batteries under 3v a cell.
If you are not 100% comfortable with using this style of battery I would advise on using NIMH or NICD only.
I have seen LIPO batteries balloon and smoke just to the point where they burst into flames INSIDE someone's AEG.
When you start to notice a ROF change in your AEG, it’s time to change your LIPO battery.

