I got my first RV used back in the early 1980s so it was probably a mid 70s model. One of the many things it did not have was a battery, there was no water pump you pressurized the tank with air. If you wanted heat you had to light a match and hold your finger on the pilot light till it got hot enough to stay lit,. The camper was so small you did not need a fan to spread the hot air around. But one night I remember well from about 30 years ago was when I was hooked up in a cement parking lot at the Grand Canyon. It was late September with shirt sleeve weather during the day. But as soon as the sun went down it dropped to below freezing. I was a cuddled up with my G/F in the back and he heater was keeping us toasty warm. Sometime in the middle of the night we both woke up freezing, the wind had blown out the pilot light and the safety shut off turned off the gas.
I spent what seemed like an eternity on my knees holding the button waiting for the thermocouple to warm up enough to take my finger off the button. It only happened once but even with the extra work required to get the heater running it was nice to have a camper that did not depend on battery power for heat. The problem is these large campers need fans to move the hot air around.
With my current setup I have 2 batteries in my truck and one in my camper which makes me confident I won't have to worry about running out of power
2010 Dodge 409 CI diesel long bed dually crew cab B&W hitch, 95 Gallon Auxiliary Transfer Fuel Tank, pulling a 33 foot Holiday Rambler Alumascape suite, Winegard SK-3005 TRAV'LER , Central vac, Splendide 2100 XC washer dryer, Rotochoks, TST Tire monitor.
Your going to need a second battery. Set your thermostat to 52 degrees and take extra blankets.
30 gallons a day...WOW! If you run your water pump dry it will not last very long...
I missed the 30 gallon a day part on first read, I am only one person with 2 dogs and won't use that much in a week.
I buy a case of bottled water, I think there are 24 or 30 (maybe 36) 12 ounce bottles to a case and a case that last me and my dogs over a week. I do drink a lot of soda but I fill up the glass with ice cubes made from bottled water.
For showers I only use a few ounces of water to get wet then shut it off and soap up, Then only use a few ounces to rinse. For washing dishes I put a couple cups of soapy water in one sink, and a few cups in a rinse sink for a total of a little over a quart. If I don't have many dishes I may do the breakfast and lunch dishes together. 30 gallons in one day is mind boggling.
I dry camped in a popup for two weeks a couple of years ago, while using the furnace once in a while. The key was careful power management. First of all, I added a second battery and a quality volt meter. I had two group 27 deep cycle batteries and never ran dry. I was using my TV to charge them up as I drove every couple of days, though, but they never got fully recharged after I left home with them. Always leave home with them fully charged. Second, I acted like I was camping in a tent and only ran the heater to take the edge off in the morning and evening. I used little LED tap lights and went to bed at sundown. I used my water pump but only about 5-10 gallons a day. I shut down all the other 12v appliances by pulling the fuse or shutting off the switches, so everything that could ran on propane. So shut off the stereo, microwave, fridge fan, whatever else is set up to draw 12v.
It sounds like they're acting as though they were home. They haven't yet learned to conserve. We don't have a generator so when dry camping somewhere between point A and point B, we conserve. We turn the hot water on propane to wash up and do any dishes. Then shut it off. I have a kerosene lantern for light rather then use the TT's lights which eat the juice. The fridge auto switches to Propane when on the road. We will use heat but haven't drained the battery yet in only one night. We use heavy quilts and fleece sheet sets. Their water usage blows me away. 30 gallons a day? They must be taking showers daily and letting the water run. In time they will learn how to conserve.