Rob, do you ever split your large packs up and use the individual packs in smaller planes? It sounds like you may have charged a couple of packs together that were unequally discharged.
I'm not sure I would feel safe charging an 8s or 9s pack in series in my house after reading Gary's unfortunate experience with his Funtana. I would be OK with it if I charged the packs individually on separate chargers but then the expense of having multiple chargers is overwhelming. I charge my 3s4p 7.8 but I only charge at 5amps, under the 1C max of 7.8amps. Packs are always cool.
These lipos are like drugs. You take your first drink of them and you want all your planes to have them. Then you end up spending more money on batteries than planes, motors, radio etc.
I've come to some peronnal conclusions about all this
1. I'd rather have fewer planes that use lipos then a whole bunch that run on older cells
2. I'm finding the 4 planes is all I can support; building, maintenance, flying, charging, repairing, storing, transporting.
3. 16 cell models are about the limit to my financial resources.
4. The only way you are getting my Lipos is prying them out of my cold dead fingers
There is obviously going to have to be safer cells/chargers developed if the lipo technology is to become mainstream in the RC industry.