? about boondocking with furnace

Maybe this was mentioned before but don't forget that the battery capacity will also be less as the temp decreases. Just one more strike.

Bordercollie wrote:
When your house battery is near dead, your 12 volt DC appliance controls on fridge etc. may not work and your generator won't start unless you have the truck engine running and charging your batteries.

This happened to us on a recent trip .... the house batteries were just a bit too far down to turn over the generator in our Class C. I just went up into the cab and held the battery boost switch in the ON position while the DW hit the generator start button back in the coach and the generator started right up.

The battery boost switch in a motorhome can be used both ways -> by holding this switch ON the coach batteries can boost the engine starting battery or the engine starting battery can boost the coach battery(ies) -> so as to start up the built-in generator to then charge the coach batteries. This is an advantage that a motorhome RV has over a towable RV.

Bordercollie wrote:
The condition of your house battery(s) also determines how long the furnace blower can run before battery(s) become discharged. An old/poorly maintained battery may only last for 4 hours of off/on furnace blower operation. When your house battery is near dead, your 12 volt DC appliance controls on fridge etc. may not work and your generator won't start unless you have the truck engine running and charging your batteries.

Yes, the problem snow-balls with the fridge dying overnight and no way to start the generator until the batteries get recharged by the chassis engine or shore/pole power. It is not a good situation to put yourself into so make sure your batteries are charged up before going to sleep.....or set your thermostat way way (way) down.

The condition of your house battery(s) also determines how long the furnace blower can run before battery(s) become discharged. An old/poorly maintained battery may only last for 4 hours of off/on furnace blower operation. When your house battery is near dead, your 12 volt DC appliance controls on fridge etc. may not work and your generator won't start unless you have the truck engine running and charging your batteries.

Also .... for those of you with Class C rig based on the Ford E-Series (E350/E450) chassis .... be sure that the cab ventilation system is set to it's recirculate setting when making camp and before shutting off the engine. This keeps cold air from entering through the cab's ventilation system on cold nights and/or in cold winds.

(The Ford E-Series chassis needs the engine running in order to change the ventilation system's air flow settings.)

We have stayed in dry camp temperatures overnight as low as 20F with a 20 MPH wind at over 6000 feet elevation. What we do is run our generator with furnace on at late as possible at night and get the interior temperature up to the 70s. This insures we start the night with a high battery charge level and will be also some time before the furnace first runs. We then set the thermostat low, 50-55F overnight. This yields a minimum interior temperature of around 48F as the thermostat is in the ceiling with the AC unit. We have -15F rated backcountry sleeping bags from our tent camping days so that relatively low temp is not an issue.

Our basement is fully enclosed so furnace heat is supplied to the basement. We also use reflectix on the windows and block off the cab with a heavy blanket. Insuring the cab heat/AC control is set to off also blocks interior airflow.

Our 2 slide outs have dual seals and produce no noticeable air leakage.

We have an infrared thermometer and that helps verify the improvement of heat retention of reflectix on the windows.

Our thermostat is located in the galley area near a large side window and front of cabin and furnace cycles on and off frequently. If it was in the bedroom furnace would probably cycle less frequently. Thermostat is located to serve both heating and AC purposes (a compromise).

I agree that the furnace will kill a battery overnight, if the battery was not well charged before going to bed.

Each motor home has it's own heat-retention factor. Slide outs generally are not well insulated and the seals are not air tight, so they will work against the furnace.

Our rig is a 2007 Phoenix Cruiser 2350 and has a conventional RV furnace and two house batteries. I don't know the furnace BTU rating. We have no slide outs. The interior volume of air in our particular rig is much less than most so there is less to heat. Adding that our floor, walls, and ceiling are very well insulated, and we have thermal glass throughout with exception to the Ford front, the house retains the heat fairly well. It helps to drape a blanket across the two front seats to create a lower-half cold-draft-blocker to minimize cold heavy air into the house.

A cold night at high-altitude in the summer can drop to the upper 30s/low 40s. Our furnace will turn on 3 or 4 times during the night with the thermostat set to 55-60, and our bedroom privacy curtain closed which is where the thermostat is located. The bedroom with thermostat is very tiny and has a heat register inside. I assume our body heat and warm breath helps to prevent the furnace from cycling more often. The thermostat is located a few feet higher than our bed, right about at my belt line which I assume also helps.



If you look close, you can see the side of our thermostat, the white thing on the wall between the bed and mirror. The silver thing just below it is a wall-mounted alarm clock.

LED panel monitors are not accurate. Check battery voltage with a voltmeter and compare to panel indicators.

We are just back from 4 days in Jasper. No hookups, no generator, 100 watt solar panel, two batteries. Raining most of the time, temps around 8 to 16 C. Battery monitor said over 90% all the time, even after morning warmup with the furnace. The key is a warm spouse. We slept best with a window and vent open, furnace off.