I had a pair of Energizer Lithium Ultimate batteries run out after only 1.5-2 hrs use in my GPS on the long weekend. They were from a pack of 4 and the first pair worked "as expected" and gave me a several days of good use (although to be honest I would've expected them to last longer).
The only thing I can think of is that perhaps they were affected by the cold? It was near freezing for parts of the first couple of days of the trip, although the day I changed them for the old set was warmish in comparison. Has anyone had this happen before?
It's a bit of a pain, and I guess in future I'll be taking 2 or more pairs of spares!