That is what I like about my Xantrex Prosine (no longer made) 2.0.
IF I set the switches properly it works as follows
IF shore/Generator power presentL: It charges the batteries
IF shore/gneerator power lost: It switches to INVERTER mode and powers TV's DVR's Computers, and optionally (If in use) microwave and kitchen/bath outlets. This includes my Wi-Fi "modem" (Wireless game adapter) that brings the internet in from afar here in the campground.
I can also disable either the battery charger (Which I have done) or the inverter (Which I did by accident a few nights ago) if I wish (I use a different converter/charger to maintain batteries, LIke it's software better, Progressive Dynamics 9180 with wizard)
When I accidently turned it off. we had a power flicker (In this RV that means 3 minutes no power) Reset everything, TV, Converters, Computers, DVR's everything.