I just charged all the batteries I have, firstly the phone didn't want to wake up, then I started unscrewing the LCD, while holding the battery with one hand, I pressed the on button, the phone booted fine one/two times, when I screwed everything back, it didn't want to get on.

Conclusions:
-It works
-there is a charging and probably a battery contact or sensor problem

I'll investigate further, does anyone knows if there are sensors (maybe hall effect) that may prevent the phone to start (like a back cover detection system or something like that) also, I noted that the phone starts more often when the LCD mechanism is open, are there any reasons ?

Thanks in advance