I just had two brand new GensAce 4s 5000mah hard case packs go bad. Purchased 3/9/2012 and used 3 or 4 times each. The tab where the positive cable connection is soldered to the battery broke off. Exactly the same on both packs. I was able to easily remove the case to discover the problem. There's double sided tape on 3 sides of the pack to hold the case on...but they didn't peel back the film where it contacts the hard case! I should not have been able to pry the case off had they assembled it properly. (my two other GensAce hard cases won't budge) I think the cells are sliding back and forth inside the case ever so slightly causing the tabs to weaken and break.

I really like the GenAce batteries, except for this big manufacturing defect on the latest batch of packs.