But surely two 18650s are just overkill. I might understand switching from the recommended LiPo cell to a single 18650 for cost cutting reasons (even though that's still probably a bad idea safety-wise), but why two?!
I have a bunch of camp badges there too and while some are really fun boards to play with I wouldn't trade safety for longer battery life with any of them.
Two 18650s also sounds like it would be heavy for a badge