Burning smell on new XPS 13 (2015 model)

I just got the new XPS 13 (2015) and after using it for 5 hours on battery power, the battery life was getting low. The laptop was installing programs, downloading stuff, etc but that doesn't explain how I got nothing near the 15 hours of claimed life (I have the 1080 screen). I was on power saver mode. The fan was running, but not often.

I hooked it up to the power outlet because and used it for another 4 hours. It was set to high performance mode and the fan was running full time while it was plugged in. Everything was fine until I noticed a burning electrical smell (9th hour) underneath the laptop near the charging port. I picked the laptop up, smelled it and was certain it was coming from inside the laptop. I could feel the laptop was mildly warm near the vents. It wasn't hot or alarming. I was using the laptop on a flat desk when I noticed the burning smell. The backlit keyboard was on and the laptop was charging.

I then unplugged it from the power cord, shut the laptop down and put the laptop in a safe area for the night.

The second day (today), I've been using the laptop for light tasks for a 4-5 hours on battery power and power saver mode and found no issues. I then connected it to the power cable and set it to high performance mode. The fans were running full time again even though I was only surfing the net. So I changed it to balanced mode and after a while it eventually quieted down to a hum.

I feel uneasy about the laptop because I don't know if it's just breaking in or if the burning smell will come back. It's such a beautiful laptop. The build quality is outstanding. But I'm unsure on what to do. Do It return it? Exchange it? Wait to see if the burning smell comes back? 

Does anyone else have the new XPS?