New battery recognized / fans not working.

So I changed the battery of my MacBook Pro (MacBook Pro 15" Unibody Early 2011) according to the guide here on Ifixit, which worked like a charm till my computer had a shut down hours later while playing LoL.

I noticed that my fans weren't quite working anymore, and thus might have caused the shut down. So I tried an SMC reset. (following exactly the steps described in this video https://www.youtube.com/watch?v=m9DkJHN6... )

Doing this the first time, the fans were running full speed but the battery wasn't recognized anymore.

I found out that the only way my battery will be recognized again is if I try : Shutting down my computer, removing my magsafe cable from the macbook, power it up, close it, (as shown at 3:00 of the previous video) then redo an SMC reset with the cable on after > But then again, the fans don't run at all.

So I have to choose between my new battery being recognized or full speed fans with no battery whatsoever.

What I tried so far :

1) Numerous SMC resets

2) Downloading Smcfancontrol (which doesn't starts the fans)

3) Repairing system permissions using disk utility

I tried putting the old battery back in, it is so old (1333 cycles) that there's an X icon over it, but the fans don't seem to be runing with it either.

(Sorry for my english, I'm french)