I have a 2 lipos in a TF Giant P-47. I charge them out of the plane in the house in a lipo sack in case they do catch fire. I also take them out of the plane when not in use. The problem is that there are 2 sides of the story with anything. Can they go up in flame just sitting there? Yes. Can they go up in flames when I charge them? Yes. Can I die walking across the street....Yes. I just take some precautions regardless by charging in the lipo sack and taking them out of the plane. Charging them outside is an idea too I never thought of, but the precautions we all are taking with the ammo box and outside just reduce the odds of something bad happen because that ammo box can still fail or something else can fail. It's just the odds of something happening are slimmer.