I checked ebay and Amazon. Cheapest I find for similar output is PowerMax PM3_35, 35 Amp for $114, and not much weight or size savings, plus no battery charger output. Instead, I'll reinstall the OE converter which outputs 30 A fine. I'll just leave the optional 5 A battery charger board disconnected and use an external 2 A charger. I'll connect it to incoming shore power before a (new) selection switch so the charger will only be ON with shore power. "Should work".
In other electrical work, I kicked the Dometic fridge to the curb since it stopped working years ago (if ever did, forget). I tried all the tricks of taking it out and leaving it upside down for weeks. They are very costly to fix or buy new. Instead I installed a "residential fridge", which only runs on 120 VAC and is what most new RV's now use. I picked a Frigidaire EFR492 4.6 cu ft, which was the only largish mini that was short enough to just fit after removing the front feet and fiberglass on top of the opening. Seems it rejects heat thru the top, so you don't want insulation there anyway. It just barely squeezed in over the bottom water tubes (w/ pry bar help). Only 1.5" gap on the sides, which is easy to fill, and doesn't protrude as much as the Dometic. I paid $220 on Amazon, then too-late saw for $189 at Walmart.
To power it w/o shore power, I bought an inverter, actually tried 5 before I found one which worked, a DATOUBOSS 1000W pure-sine inverter, $99. The fridge draws only 65W steady, but must have a large startup current since even a 500 W pure-sine didn't work. I first tried an old 400W regular inverter (square wave I assume) I had on hand. Since in the utility cabinet, I ran 2 wires from its ON switch to a DPDT switch next to the water pump switch, labelled "AC INVERTER": "ON" - "OFF". One side turns on the inverter and the other side simultaneously switches the AC outlets from the shore input (cable in box below trailer) to the inverter output. You don't want to leave the inverter on when not needed since it draws 0.7 A from the 12 V battery with no load. As with the Dometic, you want to chill down the refrigerator and contents on shore power before leaving, then switch to inverter on the road to keep it cool, which is like switching the Dometic to "DC". While driving, the tow vehicle will provide 12 V power (plus charge trailer's battery). Once stopped, if dry camping, the 12 V battery can keep the fridge cool if you go easy on door openings. I measured 7.4 ADC draw with compressor running (slightly higher than spec, but a hot day), which allows only 7 hours compressor running on my ~50 A-hr battery, but the compressor shouldn't run continuously. Some people carry a generator or solar panels when dry camping. You lose the ability to run the fridge off propane, but also lose the inefficiency of absorption refrigeration.
