Thanks for all of the feedback...
Part of my limited knowledge is the difference between a converter & inverter... and while I knew I had the former, wasn't sure if the rig also included the latter. Especially considering how these rigs are sorta meant to be used in remote locations... or that it might include an inverter for using on long periods of generator use. Anyway...
Checked the battery compartment this morning, but saw nothing unusual there... as, since I keep my small air compressor in that compartment, I usually take a peak every few weeks when I have to adjust tire pressures. The terminals were all clean with no corrosion present.
The battery itself is about 2 ½ years old... bought & installed in July 2015. It is from VMAX Solar, and is a 12 Volt 125Ah Group 31 AGM Deep Cycle Heavy Duty Battery (no, I have don't have any solar panels). As you can see in the photo, it's a completely sealed, no maintenance type... with no fluid to check.
Again, I'm probably just being paranoid... or maybe it's just my imagination that the fan seems to be cycling more often. I like the surge protector check idea, just not sure I can get outside to check it in time when it next occurs.
We'll see...