Your unit is pretty new to be having a univolt issue. I am not sure you even have a univolt on that new of a unit.
Condensation seems like the most likely to me. In Tucson, if the days are hot and the nights chilly, that could be what is causing it.
Here is a test to see where the water is coming from if the batt is in an enclosure:
Take some paper towel and tape some small pieces to the top and the sides. Let it sit and whatever part get wet, you have a clear direction. You could even use some Crayola markers or perhaps even chaulk to mark the batt in various spots to see which runs or get washed away. The trick is to monitor it every few hours so that a leak or condensation in one spot is not allowed to travel too far without being noticed.
If none are noticed in those spots, maybe there is a leak in the bottom or condensation from the bottom?? Any leak of the insides is bad, but if it is just condensation, you can get one of those battery blankets that can be placed underneath or there are some that insulate the sides. This usually protects the batt in cold temps and keeps some of the heat from getting in on hot days.
Just a thought.
Computers manufactured by companies such as IBM, Compaq and millions of others are by far the most popular with about 70 million machines in use worldwide. Macintosh fans note that cockroaches are far more numerous than humans and that numbers alone do not denote a higher life form. -NY Times 11/91