I bought a more compact charger "XIT" from China with two batteries. After a while, the batteries started being 'tight' in the camera and I had to hit the bottom of the camera on the heal of my hand to get them out far enough to pull out. I quit using them. When I examined the batteries, I noticed the case seam was partly open. I could pull on it and separate the two halves. The batteries didn't seem to be swelled or leaking, just not glued together properly.
I do like the charger--much more compact and has the fold away power plug (no cord).