I have been staying for all my cameras 1-2 cheap replacement batteries. There was some trouble, but they were solved by the supplier quickly and very accommodating. The delivered with has approximately 2/3 of the capacity of the original, it loads in about 1 1/4 hour. In both the camera and the charger he sits well and has good contact. Grade the energy hunger of my E-PL1 is an indispensable accessory.
The series dispersion seems occasionally to make trouble, in case of doubt simply request a replacement part.
Although performance is as specified somewhat lower, for the price a good thing.