those are good batteries. the danger usually isn’t when they’re in the light (except if they short out somehow, then it will happen very fast) the danger is if they are discharged too low, and then you try to charge them, or if your charger over-charges them.
Amazon will have decent prices on chargers, but not so much on the batteries. For a simple order of batteries and charger, mtn electronics is very fast anyways. And from what i’ve seen, almost all xtar chargers are very good. As for batteries, almost any protected panasonic or sanyo from a reputable seller will be good. Richard at mtn only sells good stuff. If you have questions, you can ask them here: MTN Electronics: LEDs - Batteries - Lights - Chargers - Hosts - Drivers - Components - 1-Stop-US Source