I thought that my battery was dead but not all. In fact I had installed too useless application that functioned bottom and bousillaient me the battery. Small format and voila my laptop consumes the energy properly. Think about it! In short, I always use this one and it is therefore an official no problems! And to think that it is found on the official website to 40 it is a real shame ... it's a bit like Amazon had to give them a punch in the teeth. Thank you Amazon!