How long should fully charged batteries last when using furnace in 2014 flying cloud?

[Arnoldjeff]

I recently did an overnight at a nearby barn where the owner let me boondock and stay overnight. The evening got progressively colder, and eventually hit the freezing point and we got a nice layer of snow. This was my first time using the AS in cold weather, so I was excited to try it out and use the furnace to keep warm (there was no option to connect to electric, so I could not use the heat pump – the furnace was the only option). I set the furnace to keep the AS at about 60°F through the evening hours since my dog was in the AS (2014 flying cloud) while I was in the barn with the horses. Once I settled into the AS for the night, about 10 PM, I adjusted the thermostat up to 65°F to get it a little warmer in there, as the temperature outside was dropping. I noticed my AS batteries were depleting at a pretty good pace through the evening, but I figured that since I had fully charged batteries it would surely last a while even with the furnace kicking on and off. At about 2 AM, the battery charge dropped low enough that it would not start the furnace – which made for a very long, cold night. By 7 AM, it was so cold inside the AS that I had to go outside, back my TV up to the AS, plug the AS into my TV, and keep the TV running. This began to charge the AS batteries and eventually I was able to turn the furnace on again and warm up the AS for the morning hours. My question is this – does that seem normal to you? I have heard of people using their AS all through the winter and staying warm using the furnace – are these folks in a campground somewhere connected to electric? It seems disappointing to me if the system is not designed to allow the furnace to come on and off through several cold days and nights without depleting the batteries. Please share any thoughts. Thank you!

[Mrjkq]

In that temp, yes normal furnace use draws the battery's down fast. A small generator will solve that problem & assure you & you dog a warm comfortable night.

[idroba]

The furnace in your 19 is probably the same one that is in my FC 20, that is a single outlet, relatively small furnace. Mine takes 3.6 amps with the burner on, and 2.9 amps with it off (in cool down mode). That is not enough to run your batteries down in the time frame mentioned, even if running full time, which I am sure it was not. Mine would drive me out of the trailer if run full time.

So, I have to conclude that either your batteries were not really fully charged, or more likely that they are not good. The two batteries should have a capacity of about 150 amp hours, that is they should supply your 3.6 amp load for 41 hours of run time. Since we prefer not to draw them down to less than 40%, that still would be 25 hours leaving some reserve in the batteries. Even with the refrigerator and water heater load, and some lighting use, you should get about 24 hours of use even with the furnace running.

It is common for the batteries to have a relatively short life if not kept fully charged, but not overcharged. Unfortunately the Airstream converter/charger supplied will often damage the batteries if left plugged in full time.

And if you have partly discharged the batteries and left them without recharging within a few days, you probably have damaged them.

I am not accusing you of battery abuse.... lol, but it may have happened by accident. Here is a post I did on the subject.

http://www.airforums.com/forums/f449...ml#post1602327

I hope that helps some.

[crisen]

On our 25' with (2) batteries we run the furnace overnight while traveling in cold weather without a problem. If it is very cold, as in sub-zero, I will plug in the generator for a while in the evening while we running more load, vent fans etc. Always shut it off before bed and things are fine overnight.

We do keep the furnace on while driving in these temps so the trailer is not stone cold when we stop. Typically run in the furnace at about 45-50F going down the road, mid to upper 60's in the evening and lower 60's at night. Coldest we have done this is -26F a couple years ago.

[sgschwend]

Doing the math:
Battery AH (amp hour) rating divided by 2 is the workable power available. Assuming you were at 80% charge.

Heater draw in amps time minutes run per hour divided by 60 gives AH per hour.

Not knowing your batteries or draw here is a guess:
80 AH battery de-rated to 64 AH. Half of that would be 32 usable AH.
4 amp heater, run at 30 minutes an hour is 2 AH used per hour.
Giving you 16 hours of heater run time.

Sorta sounds like your battery(s), and charging system needs fixing.

[AnnArborBob]

I am willing to bet that your batteries were either not fully charged to begin with or have been damaged by the use of the stock Airstream charger. There are lots of threads on this forum about the negative aspects of the stock Airstream charger. I'd suggest you read them for background and then, assuming you believe that you did start out with fully charged batteries before the episode you described, find someone in your area who can properly assess the health of your current batteries. If they are bad, then you need to get new ones and also a three stage (or smart) charger so you can take care of the new batteries properly.

[Arcticfox]

I'm with the others when they guess that your batteries might not have been topped up of you have a bad one.
We use our furnace a lot as we live in Canada and using it for a night without being plugged in should not be an issue at all. I have even gotten a couple nights out of ours on occasion.
Hope this helps
Cheers
Doug


Sent from my iPad using Airstream Forums

[ROBERT CROSS]

Started at "evening hours",stock batteries?, 32* & colder.....6pm? to 7am @ 60-65 pretty normal.
But test & ck the build date they could be 3+yrs old, and they may have been abused while on the dealers lot.

Bob

[cazual6]

Originally Posted by idroba

The furnace in your 19 is probably the same one that is in my FC 20, that is a single outlet, relatively small furnace. Mine takes 3.6 amps with the burner on, and 2.9 amps with it off (in cool down mode). That is not enough to run your batteries down in the time frame mentioned, even if running full time, which I am sure it was not. Mine would drive me out of the trailer if run full time.

So, I have to conclude that either your batteries were not really fully charged, or more likely that they are not good. The two batteries should have a capacity of about 150 amp hours, that is they should supply your 3.6 amp load for 41 hours of run time. Since we prefer not to draw them down to less than 40%, that still would be 25 hours leaving some reserve in the batteries. Even with the refrigerator and water heater load, and some lighting use, you should get about 24 hours of use even with the furnace running.

It is common for the batteries to have a relatively short life if not kept fully charged, but not overcharged. Unfortunately the Airstream converter/charger supplied will often damage the batteries if left plugged in full time.

And if you have partly discharged the batteries and left them without recharging within a few days, you probably have damaged them.

I am not accusing you of battery abuse.... lol, but it may have happened by accident. Here is a post I did on the subject.

http://www.airforums.com/forums/f449...ml#post1602327

I hope that helps some.

I was informed by the dealer to use the Furnace function, but if I am plugged in to either shoreline or generator, what does the heat pump do?

ArnoldJeff, I would also highly recommend you change factory installed batteries to AGM batteries. I would also recommend you get solar just to keep them charged while not in use. Keeping your AS plugged in all the time will cause life of some sort to go short, whether the batteries or other components. I got a single panel solar, which would be enough to charge the batteries during the day.

[xrvr]

Heat pump not much use below 40 degrees.

[malett]

when boondocking overnite in my 1994 34' classic i leave the trailer plugged in to my truck. i have a dodge ram diesel and it has 2 large capicity batteries and i have 2 in the camper. I have ran the heat all night, used the lighting and water pump. The truck always had enough battery left to start in zero weather. the furnace could not keep the temperature up without using my big buddy propane heater. i used propane faster than battery lol.

[kdickinson]

we found that the furnace fan will deplete the battery in our trailer, which only has one battery (I think the new models have two now) in about 2-3 hours depending of course on how much it is running. Having the battery run out on us on a cold night that was just getting colder and no electricity to be had led me to buy a back up heater. There are several good ones out there but I settled on a Camco catalytic with a quick connect to the LP supply in the trailer. The catalytic heater requires no electricity.

[gecko]

Originally Posted by malett

when boondocking overnite in my 1994 34' classic i leave the trailer plugged in to my truck. i have a dodge ram diesel and it has 2 large capicity batteries and i have 2 in the camper. I have ran the heat all night, used the lighting and water pump. The truck always had enough battery left to start in zero weather. the furnace could not keep the temperature up without using my big buddy propane heater. i used propane faster than battery lol.

Good luck with that! In our initial shakedown cruise, we managed to drain both the AS batteries and the TV batteries by morning--not a happy situation out in the boonies! Since then we've upgraded both our battery bank and the factory solar, and have not had problems.

[alano]

Understanding your battery use is key to healthy batteries and your comfort when boondocking. I haven't taken a poll but I would guess that a majority of the folks that boondock often have already invested in a battery monitor. This will display your available battery capacity and show you in real time how much current is being drawn from your batteries. This piece of equipment is key to understanding and caring for your system. Trimetric makes a nice unit if you're not looking to add a solar charger in the future. If you are considering solar, then Blue Sky has an optional battery monitor that also works very well.

[idroba]

Originally Posted by cazual6

I was informed by the dealer to use the Furnace function, but if I am plugged in to either shoreline or generator, what does the heat pump do?

The furnace function lets the furnace only run, not the heat pump. If you put the thermostat in the heat pump mode, it will run the roof AC in heat pump mode to heat the rig, assuming you are plugged into 120 volt power. The older heat pumps did not work all that well below 40 F, but the newer ones like the on on my 2014 FC 20 seems to heat well down to the upper 20's. However, they are quite noisy, much more noise than the furnace.

I don't know why the dealer would tell you to only use the furnace for heat unless they didn't want you to complain about the noise of the HP, or try to explain about the lower temp limits (or plain stupidity)

[JCWDCW]

Your batteries are likely faulty or not charged up as noted above, but the cold weather can also reduce the capacity of the batteries. You were in below freezing temps and the batteries are exposed to the outdoor temp more than the inside temperature, so voltage drop is faster than at 70 F. Even then, the calculation of 16 hours run time by sgschwend reduced for cold batteries should still have gotten you through the night.
JCW

[Buzzr]

I have a 25' Safari with 200 amp hours of Lifeline AGM Batteries. The furnace draws about 14 amps when running, or 15 amp hours for an hour of use. On cold nights,with the thermostat turned to 55 we use 60 amp hours or 30% of capacity. I have a trimetric battery monitor and I know my numbers are accurate. Obviously, he colder the night and the higher you set your thermostat, the more battery capacity you will use. The furnace is an energy hog and Airstreams are not good cold weather trailers.

[idroba]

Originally Posted by Buzzr

I have a 25' Safari with 200 amp hours of Lifeline AGM Batteries. The furnace draws about 14 amps when running, or 15 amp hours for an hour of use..

I have measured lots of RV furnaces for amp draw and have never seen one that used 14 amps when running. The largest 35,000 btuh Suburbans take under 8 amps in all my measurements. So, if yours is truly taking 14 amps, you need to check it out, as that is almost double what it should be drawing.

[gecko]

Originally Posted by idroba

I have measured lots of RV furnaces for amp draw and have never seen one that used 14 amps when running. The largest 35,000 btuh Suburbans take under 8 amps in all my measurements. So, if yours is truly taking 14 amps, you need to check it out, as that is almost double what it should be drawing.

idroba is exactly correct. Second that!

[Buzzr]

What could cause the high amp draw?