I have bought my Surface Pro 4 in December 2015 and have been using it fantastically except the battery was almost dead after about 2.5 years. The battery was not lasting for even 5 minutes. Last week, I had some difficulty with this device for which I decided to do a 'factory reset', and surprisingly, the device is working like new including it's battery! It is true! Now the battery is lasting for about 6 hours! I would strongly recommend everyone to do the same if you want to bring back your battery life. Just wanted to share with you!!
Thank you. I have an SP4 which I gave up for dead and bought an SP6. After two years it in turn seems dead. I have tried everything and none have worked. Managed to coax some charge into the sp4 and resetting now. Don't know if I can resuscitate sp6. Have tried a 60 w charger in the past. Would something more powerful have any better chance?