Heater, How long??

[eo19]

How many hours due you think I can safely run my heater off of my deep cycle battery in my Coleman Utah. I don't want to run the generator overnight.

[coach]

10-20 hours non stop

A fully charged group 24 ought to have ~ 60 amp hours available for use.
The furnace fan uses less than 4 amp/hr

60/4 = 15 hours of non stop run time.

Run the gen daily ~ 2 hours to keep the battery topped off.

[copcarguy]

It really depends on how cold and windy it is outside as well...  I have used an entire 20 pound propane tank and totally wiped out a group 27 in one night on several occasions.  I had the thermostat set in the 50's as well.  For one remote campground I go to dry camping I bring three batteries with me.  I went to the dealer and bought some more of the Coleman/Fleetwood battery connectors with the circuit breaker and the white plug that plugs into the tongue, and got a battery box for each one.  When the battery on the trailer tongue dies I unplug it and set the charged one on the ground and plug it into the camper.  
 
The furnace is the most energy hungry thing in your camper, it sure can use up both your propane and electricity!

[Booner]

The furnace is the most energy hungry thing in your camper, it sure can use up both your propane and electricity!

Found this out the hard way last week.  Camped in Moab and had a couple nights below freezing and used up the batteries.  

Just a suggestion for getting batteries recharged if you don't have a generator handy.  I took my batteries to Checker Auto and had them recharged, free.  Of course, you can only do this is you are camped close to a town with a auto parts shop.

[wavery]

10-20 hours non stop

A fully charged group 24 ought to have ~ 60 amp hours available for use.
The furnace fan uses less than 4 amp/hr

60/4 = 15 hours of non stop run time.

Run the gen daily ~ 2 hours to keep the battery topped off.

I guess it depends on the furnace and (more importantly) which battery you have.

Like Coach said.....less than 4A draw. Mine draws 2.7A. So if the furnace is actually blowing 50% of the time (30 minutes out of each hour) you should get 2 full nights out of one charge. However, you will also have other loads on the battery. I would, at least, bring a back-up battery for a weekend, just in case.

[Mike Up]

While I never used it for the PUP, I did use it for tent camping. I bought a Mr. Heater Big Buddy Heater. It's the larger 18,000 BTU heater that uses 2 portable propane tanks. It uses D batteries for the fan (which is not needed) and puts out more heat than either of my Pop Up Furnaces did at 16,000 & 17,000 BTU.
 
It's also 100% efficient since it uses no heat exchanger BUT does lose efficiency because it requires a window open to bring in fresh oxygen for combustion. It's safe to use indoors and supposedly creates no CO (Carbon Monoxide) and even comes with a low O2 sensor alarm. This could be used in conjection with a CO alarm as well. We usually only have it on in the tent when were awake and use a very warm sleeping bag with a blanket over us. If we were going to use it with the Pop Up, we also were going to put a blanket under the mattress to help keep some of the cold out.
 
With the tent, we used cots to stay off the ground and keep the cold air out from under us. With a Pop Up, you are essentially exposed to the same cold as being on the ground since the underside of the bunkend is exposed to the outside cold.
 
I know in the winter months when I ran the furnace (while at home) to keep it warm while I did things in it, it ate the propane and battery. I kept it about 50 degrees and only ran it about 3 or 4 hours a day. In a few days with temps in the 20's and 30's, I run one tank empty and would need to recharge my battery. So running it at 50 degrees for 12 hours in 20 - 30 degree temps, you should run your propane out and run your battery down.
 
If I were going to boondock in my Camper, I use my Mr. Heater during the day and use warm sleeping bags and blankets for sleeping. For sleeping set the thermostat on the main furnace for 50 degrees and bring 2 20# propane tanks on the tongue along with a group 31 battery. Then I'd also bring another tank in the back of the truck along with another group 31 battery. I'd only keep one battery on the tongue for towing as that would make a very heavy tongue weight.
 
Good luck and have a good one.