Richard Saville (Average Man) saw a lot of people at Pi Wars 2015 using LiPo batteries to power their robots. He had always heard of the dangers of using these batteries and was more than a little wary of doing so. However, he has now looked into the comparative dangers of using different types of packs and decided to give LiPos a go, erring on the side of caution (as one should when dealing with bang-y type thingies). He’s written an introduction to the batteries here, and it’s well worth a read if you’re interested in making your Pi portable or wireless.