When I had lost my charger, I have long wondered about buying a cheap accessory charger. However, there are countless poor reviews of the devices that appear to have all the same origin in spite of many different names. In addition, the accessory chargers are significantly larger than the original. So I do not regret having me ultimately decided again for the original.
Suitable charger is the way for the CP-FM500H batteries the SLT Alpha cameras, in my case, the SLT-A77.