Having lipo problems

[Savage03]

Recently I have been having lipos go bad on me, I have 3 I use in my minis(tamtechs) and over the winter my 2 hyperion 1800mah 2s packs I guess went bad, I left a charge on them peridically, I went out to charge one and it was very puffed and the other one would start getting warm as it was charging, I contacted B.P.P who i got em from and he said their done stop using them, great 2 pretty new packs down the tube.
So we move on to my other one which is even worse since it hasnt even had 6 full runs on it since getting, its a maxamps 2100mah 2s, went out just now to charge it for my Tamtech Hotshot and it started to puff on the charger! Im so ticked I cant stand it. I use a hyperion balancer, hyperion or ice charger and have never ran the packs to cut off in the cars, pretty much always leave a good amount left on them.
So I see alot maxamps bashing so besides that is something going on here im missing? Before I go buy 3 more lipos like to know maybe if im doing something wrong.
Thanks