Our camping is almost exclusively dry camping up until now. While it was in a different brand of RV, the fridge is a Dometic, and the battery and charging systems are pretty much the same as the Keystones.
Typically, we use some lights in the evening for reading and the fridge runs 24/7 on propane/12vdc. The hot water heater also uses a small amount of 12vdc for its control circuits. Because we can use the generator for a couple of hours each day in NYS parks, we've gotten a bit lax about energy conservation. I have converted some of the lights to LED's but that is an ongoing project.
Two big users of 12vdc that no one thinks about are the propane detector and the AM/FM/CD/DVD radio unit. Even when turned off, the radio continues to consume electricity. The propane detector pulls amperage 24/7.
So, if you want your battery to last 4 days to control the fridge, at a minimum, do the following:
- Pull the fuse on the propane detector
- Pull the fuse on the AM/FM radio
- Pull the fuse on the hot water heater
- Make sure ALL lights and other 12vdc appliances are off or unplugged
- Make sure the battery is fully charged before you leave it
- Double check and then check again that there is nothing else using any 12vdc before you leave
Even with all the above, if your battery is not up to snuff, it may not go the 4 days. Age and past treatment of the battery comes into play here.
As an aside, I am going to be learning about 12vdc conservation all over again with our new trailer. All the systems are "bigger" and the lighting is more extensive. Bigger fridge, too.