Marketplace
I bought a battery on Ebay for a Samsung s3 battery. At first battery was OK. Bad, fake or non genuine batteries I read get hot quicker and overtime battery bulges and the weight of the battery is heavier. Beware of batteries that are labeled brand new genuine OEM battery. There are a lot of sellers selling bad batteries on Ebay.
https://www.ozbargain.com.au/node/183884#comment-2584137