One of the biggest complaints about the Galaxy S6 is the fact that is doesn’t have a removable battery. Supposedly the manual says that it is replaceable, but it’s not as simple as popping it out like you could on all previous Galaxy S phones. You can’t just rip off the back either.
The folks over at My Fix Guide disassembled the Galaxy S6 with complete instructions, but I have to stress that if you don’t have a lot of experience with this stuff, you would be better off letting a pro handle it. You’re going to have to heat up the back cover with a heat gun in order to remove it. Then you will have to remove the middle frame, nfc chip, and motherboard.
If you’re a brave soul, they did post pictures along with complete instructions. Just hit up the source link for more info.