XPS15 9530 Poor Battery Life

Hello,

Work bought me an XPS 15 9530 in early 2014. It had very light use for the subsequent year, and was almost always used plugged in with the AC adapter. Now I have started to need to use it more without the adapter, but I notice the battery life is appalling. It was sold with up to 11h of battery life (61k mWh battery). But 'up to' cannot equate to the current 2-3h I am lucky to get - even with extremely light use.

I read on another post that the graphics drivers may be the issue, so I have updated both the Nvidia (version 353.06) and Intel (version 10.18.14.4222) drivers. This hasn't helped. I have downloaded a small program (BatteryBar) to assess the battery. It reports I have 14.7% battery wear, but surely this shouldn't impact the battery life from the advertised 'up to' 11h to 2-3h.

Does anyone know how to fix this (other than a new battery - which I have read in other posts doesn't seem to work)?

Alternatively - how do I complain to Dell, that a laptop which cost ~£1300 and was advertised with 'up to' 11h of battery life seems to be performing so appallingly below par. I have read on other posts that Dell have in the past repeated it was advertised as "up to" - but that is wholly misleading if the user actually experiences 2-3h.

Looking forward to hearing your suggestions regarding fixing/complaining.

Thank you, Batterywoes