Charger recommendation

It's hard to give advice without knowing the important variables. How you are going to use the trailer? Are you boondocking? If so, for how long? What are you going to run off the power port? What's the battery type and capacity?

According to Fiamm that model battery is made for uninterrupted power supplies, like the ones that keep your computer running for a few minutes when the power goes out, at a high rate of discharge. They're meant to put their amps out fast to give you time to save your work and shut down your computer or start a backup power source like a generator, then to be charged slowly until the next outage occurs.

I'm no AGM chemistry expert so I don't know what the effects are, if any, of a slow discharge like you get camping. But reading all the documents Fiamm had on their website, the only charging voltage they give is the float voltage, 13.62 @77 degrees. No bulk or absorption voltages are given. That implies that they want nothing more than trickle charging, which makes sense, since UPC batteries are meant to be on a charger 24/7 for weeks or months at a time between power outages, so they have plenty of time to be charged very slowly to avoid gassing. It also implies that a standard RV 3-stage converter is out. Looks like if you find a trickle charger/maintainer that operates at @ 13.62v, you should be OK. But it's not a battery you could deep discharge and fully charge every day without eventually killing it, so minimizing usage would be the way to get the longest life out of it.

The key thing to remember about inverters is that for every amp of 110v you need, it takes 10 amps from the battery.