GRJ....This is a topic I have hands on experience with.My other hobby is building and flying R/C airplanes. (as if I needed two hobbies) For your Camelback project LiPo is likely your only choice. They are available in many sizes and shapes and have high energy density. These cells are safe when handled properly and charged with the right charger. Many fliers use these and remove and store them in a fireproof container. MUST be reduced to a storage charge for long term storage. A club member here burned his house down with these. Not the battery's fault but he still lost his house.
NiMh is not suitable for high drain or fast charge. I use then in most of my transmitters.
Lilon safer version of LiPoly...built in a metal tube. Some can take a reasonably fast charge.
A123 now Lithiumwerks Nanophosphate....My personal choice for aircraft radios and servos. Not a fire hazard, fast charge,store fully charged for years no problem. LiPo4 are a poor cousin do not have the fast charge or long life.
Difference between aircraft and model train use. NO PTC or fuses are used in aircraft packs. Failure mode is a fast moving object coming down right now. Don Sweet's packs appear to be protected and possibly use a controller on board to handle charge.
Chargers are important. I use and recommend CellPro Power Lab 6. US designed and sold/supported, Asian made.Supports almost all battery types. Many people start with a cheapo and end up with a good charger like this one.
Richard
