Hola Clay, and welcome to the forum.
You may want to read up on or watch a few videos about electrical systems of RVs to get a basic understanding as this will make your RV life much more pleasant.
Your question about "charge" probably relates to something known as battery capacity vs system draw, and the answer is really "it depends".
Imagine your camper as a Flashlight... You put a battery in, turn it on, and it illuminates stuff. For how long? Like I said, depends... in my simplified example, how powerful of a battery, and how bright the bulb. A smaller battery will be empty quicker, but if you turn down the brightness, it may last longer.
How long before you have to recharge depends on those two things. Plus, your camper may come with solar panels which, if your energy usage is humble, could be able to fill up the Batteries for almost unlimited boondocking.