Dry camping with furnace on
I was dry camping this weekend and had to put the furnace on for the first time. I was worried that I would kill the battery if I ran the furnace overnight. I was right :(. The house battery was ...
Forum Discussion
I'm a bit confused by the short battery life with furnace use comments here.
In high 30's temps at night our furnace cycles nicely when set at 60 degrees - about 5 minutes ON every 15 minutes or so. It's blower draws round 7 amps when it's running ... so cycling such that it's ON 5 minutes around 4 times every 60 minutes means it runs about 4 times X 5 minutes = 20 minutes every 60 minutes. This means that it consumes about 1/3 of 7 amp-hours = 2.33 amp-hours every hour on a high 30's temperatures night.
For a 10 hour night run this means that it consumes only about 23 amp-hours of our 230 amp-hour 12V AGM deep cycle battery bank's capacity.
We also run a couple of CPAP machines at night (room temp air only - no heat). Our batteries easily go 2-3 days this way before needing charging after dropping them down to around a 40 per cent state of charge (60 per cent of capacity used). We have a small 24 foot Class C that we block off the cab area on and our furnace is a 26,000 BTU one. We keep all shades drawn to better trap a layer of insulating air between the shades and the window glass. We also wedge a sheet of insulating material between the the shade and the window glass on one window by the bed. We do not have any solar on board.
I wonder why some of you are experiencing such short battery life with furnace use? Our propane furnace has worked well so far without seeming to be a battery hog at all - but we have not yet tried to drycamp in 20 degree weather!
In high 30's temps at night our furnace cycles nicely when set at 60 degrees - about 5 minutes ON every 15 minutes or so. It's blower draws round 7 amps when it's running ... so cycling such that it's ON 5 minutes around 4 times every 60 minutes means it runs about 4 times X 5 minutes = 20 minutes every 60 minutes. This means that it consumes about 1/3 of 7 amp-hours = 2.33 amp-hours every hour on a high 30's temperatures night.
For a 10 hour night run this means that it consumes only about 23 amp-hours of our 230 amp-hour 12V AGM deep cycle battery bank's capacity.
We also run a couple of CPAP machines at night (room temp air only - no heat). Our batteries easily go 2-3 days this way before needing charging after dropping them down to around a 40 per cent state of charge (60 per cent of capacity used). We have a small 24 foot Class C that we block off the cab area on and our furnace is a 26,000 BTU one. We keep all shades drawn to better trap a layer of insulating air between the shades and the window glass. We also wedge a sheet of insulating material between the the shade and the window glass on one window by the bed. We do not have any solar on board.
I wonder why some of you are experiencing such short battery life with furnace use? Our propane furnace has worked well so far without seeming to be a battery hog at all - but we have not yet tried to drycamp in 20 degree weather!
