Whats an easy way to get hold of Energy Crystals?

I know Behemoths carry them along with Ruby Dragons but the gits never seem to drop them after battle. I'm using the Rare Items ability and level up but it dosn't seem to be helping. The enemys always seem to drop something else or nothing at all.

I assume it's just a case of trying over and over until you get what you want. Just takes so damn long.

Whats annoying is I managed to get hold of the things the first time I played through the game but this time I just can't get any. I want to get all the characters final weapons on before I go to Ultimecias castle.

I need to get 7 of the things and can't even get one at the moment. Grrrrrrrrrrrrrrrrr. :grr: