Awesome thank you. Can you tell me what the battery will power on the camper? See I am going on a camping trip to a country music concert in July and I want to make sure I have all I need to keep my sunline going for the 8 days we will be there. I know I have a million questions.
Your camper has 2 different power systems.
12 volts DC (the battery power) This powers the lights inside and out, the water pump, the furnace, the fridge control system, maybe the hot water heater control system (your HW heater may be all gas controlled being as old as it is), a radio inside if yours has one.
120 Volts AC (VAC) (power like in your house) When the camper is plugged into shore power, it powers up 120 VAC wall outlets that you can plug some limited amperage devices into. It also powers up a power converter that uses 120 VAC and makes 12 volt DC to charge the battery and create excess 12 volts DC to run the DC volt devices. If your camper has a 120 volt element on the fridge, it can run LP gas or 120 VAC. If it has a roof AC unit, this needs the 120 VAC, if yours has a microwave it runs this.
Basically, the camper is self contained using LP gas and 12 volt DC devices. While you cannot plug in your toaster, or other 120 VAC electrical devices when running on battery, you can camp very comfortably.
You asked about how to keep the Sunline going for 8 days, is this with no ability to plug into 120 VAC? If so that will be complex to run everything in the camper on the one battery charge. But, knowing some how of this works, the battery can be used for critical things. If your fridge works, it runs on propane gas and uses only a little battery power. Keeping your food cold is very important.
Using the standard incandescent lights in the camper, uses a lot of power when running on battery only. If you are plugged into shore power, then no problem. In this case you can buy a few LED lights in key locations and only use them when really needed. Flashlights will work the rest of the time. Some camper folks also bring a spare fully charged battery as a back up. If the first one gets drained down to low, they change the battery to a fresh charged one. You still need to be a power miser but it is a back up plan.
Those of us who live off the grid (no 120 VAC power hook up at the campground, we call this Boondocking) we take special precautions to reduce power. We convert the camper to LED lights to reduce power, we have bigger batteries and we have a method on how to recharge the batteries. Some use solar cells to recharge others use portable generators. Us boodockers adapt to being a power miser group and once you are past the learning curve, it is not that hard.
That said, there are ways that you can get through your 8 days without trying to figure out how to covert your camper into a power miser, you just may have to give up some features. Think of this like tent camping, just you have a camper instead of a tent. The fridge can work well for you and uses very little power on gas, you can use the gas stove. The water pump if use very sparingly can be used. Think about using camp water in place of the camper water for big jobs. You onboard water and waste tanks will have a hard time going 8 days but you can manage that too to make it last. Take showers at a shower house (if there is one) wash dishes outside on the picnic table and heat the water on a camp stove. Again, think tent camping but with extra luxuries, just not full RV mode.
Hope this helps
John