My original Samsung battery for my S3 mini died after just one year. I’ve had good experience with cheap batteries from eBay before, but the replacement I bought this time made my phone behave rather unstable. That’s why I thought I’d take an X-ray of them to see how different they where.
I replaced the cheap 1500mAh battery with a slightly more expensive “gold” battery that turned out return the phone to a stable state and have acceptable battery life. Here is what they look like:
And a x-ray:
While it is impossible to say much about the quality of electronics with a simple x-ray the impression is at least the the cheapest e-bay has a simpler circuit. I don’t believe that the gold battery actually has 2450mAh, but at least it works just as good as the original.