Not an expert by any means but it appears that this is both an inverter and a battery charger (makes sense as it's for boats). I think that if you wire it correctly, you can use it as a normal inverter and can also plug 110 into it and it will charger your battery(ies). I guess that would make sense if you were at a camp site, for example, with 110 available and had a bunch of 110 stuff permanently wired into your 80 (e.g. fridge). You could then drop a lead from the inverter/charger into the 110 and not draw down your battery.
The specs also say that it draws <3 amps under no-load conditions. That probably means that it generates almost 3 amps of heat with nothing plugged into it. Therefore, I would make sure you wire it with a convenient on-off switch so that it isn't on except when you want it to be.
Great score though....let me know if you decide not to install and I'll take it off your hands!
