thanks andersonwal for that link to r/c calculations, thats what i was looking for when i was building my life packs using old laptop batteries
Personally, i think if you get the cheap lipos at 20 dollars a pack, you can buy 5 for the price of one at your local shop and if one goes bad, your only out 20 bucks and you can easily afford a new one.
Splitting Lipo packs is definitely not for the inexperienced. It involves using a METAL soldering iron to un-solder the individual cell tabs that sit only millimeters from eachother. One small slip and you can have a disaster. I've been soldering for 10+ years and have split and rebuilt countless Lipos packs and I still get a little nervous when I'm tearing into them.
RCN has considered a tutorial for this very procedure but decided against it because of the raw danger involved.
They can explode if soldered incorrectly, or if the paste inside gets to hot it can explode, you can accidentally cut the cell when cutting the pack which can make it explode, and much more.