This should have been in my first post- This is what happens when you try to suck em down cold.
http://www.rc-monster.com/forum/showthread.php?t=24836
Remember the temperature gets MORE critical as the C ratings go up. For example you have a 10C rated pack (I know, there's only
one company making those, and they are labeled at 60C, sorry that's my random stab at MA today) it will be pushed much harder, and produce more of it's own heat, sooner. Take a 30C pack that normally won't get hot even in the summer---- you see the problem. I would even suggest preheating, as I did in the linked thread. Just keep em happy!