I have noticed this before but never gave it any thought. Everyone always talks about puffed lipos, and if their pack is puffed because the heat shrink feels like it has ballooned away from the battery, but I never hear about the lipo packs that change shape, but are still hard. In that you can't feel that puffiness and it is still as hard as a new pack but when compared to another pack of the same model, you can visually see the difference in shape.

What is going on there? Is that puffed?

These are new Turnigy Nano-tech 5000mah that I have in question, but have noticed it with others too.

Hi there. I think I mentioned this in a previous post: 2 modes of failure for Lipo with expanstions.
1. Soft puff. Basically over or under voltage of the cells. This is usually the users fault
2. Hard Puff (expansion). Chemical crystalization of ions internally. Due to poor seection of chemistry and unable to deliver the cycle count.

Thanks for the reply. Is it as dangerous as a soft puff?