Won't Charge Batteries. Upgrade?

[porthas]

Hey folks,

New owner here, bought a used 2016 trailer 30' flying cloud (30FB). We went on our first trip boondocking just to find out a day later that our power goes out if we are not running our generator. As a generator, we've got Predator 3500. Once home, we found out that while we were driving - the batteries charged quite a bit but the juice ran out a couple of hours later as the trip is only about 10 miles. I plugged the trailer to 110 for a day. Checked a day later but still no juice with batteries. I tried all combinations, Storage / Use and inverter on/off.
As far as my converter (is that same as inverter?) I have Intertek Series 5300.

As I have been reading through the forums, I see that there are many recommendations to upgrade my converter so that the batteries can be charged. Would that be right to assume that those cannot be charged any other way? That's quite odd.

Now I am thinking to actually upgrade the batteries so when boondocking they last a bit longer. Thinking of LFP. I assume i would need to upgrade the converter, batter pack, and to have some work done on the roof as well to attach solar panels and wire those to the trailer. Is this difficult to do on your own or shall I hire an electrician or an RV expert? Also any recommendations on any particular hardware? On youtube I see a lot of recommendations for Renogy and Batter Born.

Thank you!

[Acheron2010]

Before you do that, inspect and charge your batteries using either an external charger, or a campground 30 or 50 amp connection, whichever ur trailer has. No stock Airstream will last an overnight on just batteries with normal use plus a heater unless you are very conservative on power usage. Lots of posts in the forum on calculating power usage. Easiest to do it while in a full hookup camp, and with fully charged batteries, go about your normal routine. You will quickly find out how long you can last unplugged, then, plug in, and start looking at lithium upgrades, solar panels and generators. Welcome to Airstream camping.