Two 12 volt batteries? Are they also group 24 which is the smallest available? Even if they are group 27 they are still minimal and may not carry all that. It's very common to upgrade to four GC2. You also have to look at your charging capabilities.
During my first year I ran a four pack GC2, led bulbs, propane fridge, 42" led tv, lap top, cell phones, ceiling fan and plenty of furnace and I'd usually be down to 12.2 or a little less. I wasn't inverting to heavy devices. Your inverter isn't drawing too much power. It's probably drawing .5 to .7 amps. That's 500 to 700 milli amps 5/10 to 7/10 of an amp. When DW was done watching tv late at night she would shut of the inverter with a remote button which saved about .7 A x 8 hours = 5.6 amp hours.
In order to put all those amp hours back in the next day I had upgraded the converter to a Progressive Dynamics PD 4655 with 14.4 volt capability. Even with a better charging source it will probably take 6 hours or so to put all those amp hours back in. You can do 3 or 4 hour charges and not return 100 % and possibly make it through the next night but each day your battery specific gravity will drop lower and lower.
As the gravity reading drops each day you end up with what amounts to a smaller and smaller battery. You may see 14.4 volts when charging and you may see 12.6 resting but the battery wont perform because it hasn't been fully charged. You also get into the issue of what generator you are charging with. You dont need a 5000 RV installed generator to charge your batteries so people will often times use something smaller and quieter like a Honda or Champion etc inverter.
There is no one size fits all answer to much of this. Everyone accomplishes it in different ways so you need to look at the whole picture and build your system. I accomplished it by setting out to be just as comfortable as when at home and have spent about $5,000 or more from generator to inverter to panels on the roof.
The second year I added 520 watts of solar which would usually have me fully charged each day. For poor solar days I also added a manual power supply which helped the PD4655 and could also be used to equalize. There are better converters available that will go to 14.8 volts so dont buy what I did. If you are always going to charge with a genny then you want to build an efficient system based on that. If you are going to run a decent solar bank then you can put less emphasis on genny charging and live with the RV generator and perhaps the oem converter. The oem converter can some times not be a very good model.
You need to do an energy audit to get some idea of what's going on.
You battery bank is your savings account.
Your overnight use is your withdrawals.
Your charging sources are your income.
While charging you also have to pay extra because of system resistance. If you use 100 amp hours you may need to create about 112 amp hours return.
Everything you are using from your tank monitor or propane sniffer to stereo to satellite are using amperage. That amperage times how long it is drawn equals amp hours. Just letting your rig sit there with the fridge on propane and no lights on or anything is probably pulling 1 to 1.5 amps. 1.5 x 24 hr = 36 amp hours. A group 24 battery is probably 85 amp hours and only about half or less of that amp hour rating are available without discharging too deeply. So one of those batteries is only good for day or so. When people shut off their fridge and leave the rv in storage they will come back to stone dead batteries after a week or two.
