Agreed, and it seems to stem from the NiMH requirement. Maybe designing a protective shell around a LiPO battery (to avoid puncture damage) would have made more sense?

Pretty impressive work though! I think you must have learned a lot. I've spent quite some time on about 5 different projects that were way less polished, but it seems we have picked up the same level of skills along the way. The post is very recognizable ;) Looking forward to the your project!