I have the i7 256GB touchscreen and used to get about 6-8 hours battery life but it's declined to about 4 hours after 6 months of use. I finally contacted Dell and according to their tech, this is "normal wear and tear" and the average life span is only "a year to a year and a half". He then proceeded to install a battery management software on my system and said that my battery health is good even though the performance has dropped about 50% in less than a year! I asked to speak to a supervisor and the supervisor said that I am "lucky to be getting 3-4 hours backup battery"... I asked him to tell me where on the Dell website does it say that it should be like that and he in return asked me to tell him where on the website does it say that I should be getting more! I was so upset by the supervisor that I forgot to mention the annoying buzzing sound that has plagued my laptop since I received it. I just emailed support and hope that they can be more helpful than the tech that I spoke to on the phone.