battery not charging

Take your battery down to any tire or auto parts house and they will load test it for free - eliminates "bad battery" question.

Propane alarms have limited life and when they get old they can go bonkers whether you have good battery or not.

Since the water pump should work off of the battery, having to plug into 120v to run the water pump means the battery is not supplying power to the RV. There can be many causes.

1. battery disconnected via disconnect switch
2. bettery dead and won't take/hold charge
3. loose connections from battery to RV. Check the ground as well as the hot wire
4. blown reverse polarity fuses on the converter 12v board
5. converter is bad and won't charge the battery, so it ran down

I consider #5 to be unlikely since the converter ran the water pump when plugged in.

Hoping the converter/charger was not turned off by flipping its 120VAC breaker when you hooked up to the house 120VAC Receptacle... The converter/charger being run from the 30AMP Shore Power cable is what was suppose to run your 12VDC items including the water pump as well as charging your on-board battery. Actually the charged up battery would have run your water pump just fine if it was connected to your 12VDC Distribution Panel not required to be hooked up to Shore Power.

Also hope you had all three conductor of the shore power cable connected to your house 120VAC 15A receptacle through the approved type RV30A-15A adapter..

Whenever we hook up to to shore power we always do a quick check with a DC MULTIMETER across the battery terminals to see if it is getting a charge from the converter/charger unit when hooked up to shore power. The battery terminals will read 12.6VDC when fully charged and will jump up to 13.6VDC if it is connected to the converter/charger unit if it is working...

Lots of things to learn about how the trailer works to keep ahead of situations...

Roy Ken

Assuming you're talking about a single 12 volt lead acid battery & if you have a multimeter & hydrometer, you could start by checking its condition prior to attempted charging. Check the water levels in each cell, if lead acid, fill just below slot with distilled water only, if needed.
12.6 + volt reading = fully charged battery

I gather from your posting, the pump, lights etc do not work unless you are connected to shore power. Correct ?

Let that portable work at least 24 hours.
I assume it is automatic and will float or shut off when done.