I bought some BTY batteries from a Hong Kong seller last year and i was totally conned. They didn't reply to any of my emails and i had already left positive feedback so i couldn't do anything else about it.
The batteries are cheap for a reason, they don't charge and heat up dangerously whilst charging and feel like they will explode.
The ones i bought were 2500mAh ones and they lasted about 30 photos in my Sony Camera whereas the original Sony 2500Mah batteries last 200 photos.
So if you are thinking about buying cheap Ni Mh batteries from Hong Kong and China please don't as most of them are fake dangerous pieces of rubbish. Spend a bit more on branded batteries to save yourself a headache.
I am now only buying branded Ni Mh batteries from reputable UK sellers.
Ebay should ban these sellers from selling these fake dangerous batteries.