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Author Topic: Power consumption?  (Read 4444 times)

test1328

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Power consumption?
« on: December 09, 2013, 06:25:53 PM »
I'm trying to figure out just how much power is being pulled by my furnace and/or refrigerator/freezer when using strictly 12V.  I have a 2008 Dutchmen 18ft travel trailer and use it while hunting and for camping.  During hunting season, it can get quite cold and the furnace runs more at night.  Typically I just keep it on the lowest setting and it seems to come on around 55-58F, so it's not like I'm trying to keep it at 70F for comfort.  The only other things that use electricity are the refrigerator and radio.  I have a power cut-off switch installed that I switch off during the day when I'm not there to make sure nothing is running while I'm away, basically to conserve the battery power.  However, after 2 nights, the battery power is sufficiently low that it won't run the furnace.  I have two new marine batteries installed, connected in parallel and I know they are good batteries.  I'd like to figure out a way that I can run the furnace more than two nights without draining the battery.  I'm not sure how much the amp draw from the refrigerator is, but I wouldn't think it is very much since it is mainly running on propane.  If anyone has any ideas about extending the life of the batteries, I would appreciate hearing about it and if I should be able to run it longer than 2 nights, then can you suggest what I might look at to fix the problem?
2008 Dutchmen 18BH

SeilerBird

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Re: Power consumption?
« Reply #1 on: December 09, 2013, 06:34:58 PM »
Rather that adding more batteries what I did was to add more covers on to the bed. I don't run the furnace at all at night.

Great Horned Owl

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Re: Power consumption?
« Reply #2 on: December 09, 2013, 08:37:54 PM »
You might consider installing a ventless propane heater that uses no electricity at all. My preference would be one of the Olympic Wave series of catalytic heaters from Camco. Some people like the Buddy heaters.

Joel
Joel & Dorothy
Retired electronics engineer. Avid photographer, paddler & birder.
2011 Silverado 2500HD, Duramax, 4x4,crew cab, 8' bed
Palomino Puma 253-FBS  27' 5th wheel
1994 19' Class B Horizon / Chevy

Mavarick

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Re: Power consumption?
« Reply #3 on: December 09, 2013, 11:40:49 PM »
Just guessing here not knowing the specifics etc but your batteries are probably too small to run fridge, furnace, etc for much longer than 2 days while dry camping. I imagine you want to stay up hunting for a week or so and that means some major changes in battery power etc and or propane equipment. The simplest and cheapest fix might be to just bring along a small Honda genset that can run during the day and charge your batteries so you can actually use the appliances without worry. They donít use much fuel, they are quiet and you can use a charger you probably already have to keep the batteries up. Welcome to the forum also.
2009 Tiffin Allegro Bus 43 QRP
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SmokerBill

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Re: Power consumption?
« Reply #4 on: December 10, 2013, 08:48:57 AM »
The Mr. Heater Big Buddy heater would be a good option for you. It got down to 24 degrees here last night, and when I woke up this morning, the temp in my trailer was a comfy 66. Just make sure you provide for ventilation. I keep one window partially open and the bath ceiling vent cracked.  In addition to the fact that there's no draw on your batteries, the heater uses less propane than your furnace.
Bill
2011 Jayco 26BH
2011 1500 Dodge Ram, Hemi Powered!

Great Horned Owl

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  • Lake county, IL
Re: Power consumption?
« Reply #5 on: December 10, 2013, 09:30:30 AM »
The Mr. Heater Big Buddy heater would be a good option for you. It got down to 24 degrees here last night, and when I woke up this morning, the temp in my trailer was a comfy 66. Just make sure you provide for ventilation. I keep one window partially open and the bath ceiling vent cracked.  In addition to the fact that there's no draw on your batteries, the heater uses less propane than your furnace.

One possible problem with the Buddy heaters is their low oxygen sensor. It is a needed safety feature on that type (blue flame) of heater, but it prevents operation at higher elevations. The catalytic heaters such as the Olympic Wave series do not need the low oxygen sensor, and do not have an altitude limitation.

Joel
Joel & Dorothy
Retired electronics engineer. Avid photographer, paddler & birder.
2011 Silverado 2500HD, Duramax, 4x4,crew cab, 8' bed
Palomino Puma 253-FBS  27' 5th wheel
1994 19' Class B Horizon / Chevy

SmokerBill

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Re: Power consumption?
« Reply #6 on: December 10, 2013, 09:43:03 AM »
You're right about the fact that the Buddy heaters could have problems at higher elevations because of the oxygen sensor doing its job, Joel (7000+ feet according to the manual), but they aren't blue flame heaters. They have ceramic grid panels that burn bright orange. Some of their other heaters are blue flame, though.
Bill
2011 Jayco 26BH
2011 1500 Dodge Ram, Hemi Powered!

Marsha/CA

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Re: Power consumption?
« Reply #7 on: December 10, 2013, 10:54:53 AM »
To answer the OP question.   You will draw down your batteries quickly using the furnace.  The fan is a big consumer. 

An easy fix to all this is to run a portable generator.  Before we bought our motor home, we had a slide in truck camper for lots of years.  It only had one battery and we would go out to the boondocks with our horses.  We bought a 2000 watt Honda and would run it for about an hour in the morning and an hour at night.  That would keep the battery charged up and everything working.......and us warm.

Marsha~
2017 Heartland Mallard IDM231 Travel Trailer....Small but mighty.

Clay L

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Re: Power consumption?
« Reply #8 on: December 10, 2013, 11:19:27 AM »
As stated the fan is a fairly large draw - 7 amps as I recall.
I haven't boon docked with this motor home but with my last one I used to get one night with the furnace running and I had one battery and I still had power left.

Any lights you have on will draw additional current - maybe an amp per light.

 Also depending on what you used to charge the batteries it can take 24 hours or so to fully charge them.
Clay (WA5NMR), Lee (Wife), Katie & Kelli (cats), Sali (toy poodle)
Settled down after full timing for eleven years and snowbirding for one year in a 2004 Winnebago 35N Sightseer, Workhorse W 20 Chassis. Honda toad

test1328

  • Posts: 2
Re: Power consumption?
« Reply #9 on: December 10, 2013, 01:48:29 PM »
Thanks for the input everyone.  I truly appreciate your help.  Clay, you're right, the amp draw for the furnace fan is 7 amps.  I was just figuring that with two batteries, that the battery power should last longer than two nights.  I figured that the fan probably runs no more than 2-3 hours total in an 8 hour period so that is only 21 amp-hours a night max.  Times 2 nights and you have 42 amp-hours.  I would think that isn't too much, but maybe it is.  That is why I was wondering what the refrigerator might draw?  I'm not sure how the refrigerator works, but I didn't think it used electricity when running on LP, but I do know that it shuts down when I turn the power off, so it must require some.

In any case, it sounds like a generator might be the way to go.  Plugging the camper into the AC from the generator should provide the power to charge the battery, right?

As far as the Mr. Buddy type heaters, do the people that use them in their trailers install them someplace or do you just leave them freestanding so that you can move them where you want them?  Thanks also for the comments on the high altitude.  I commonly camp/hunt at 10,000 ft elevation or higher, so that is a big consideration.

Again, thanks for all the help.
2008 Dutchmen 18BH

Gary RV_Wizard

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Re: Power consumption?
« Reply #10 on: December 10, 2013, 03:10:02 PM »
Quote
I have two new marine batteries installed, connected in parallel and I know they are good batteries.

The 42 AH you estimated is probably about half of what a typical pair of marine batteries (size 24) could supply. Either you have additional draws you aren't aware of, or those batteries aren't as good as you think. Or maybe they don't ever get fully re-charged after use. People often think a few hours of charging is enough, but that rarely gets them higher than 80%. It may take 16-20 hours of charging to actually reach 100%.

The fridge uses a tiny bit of 12v for its controller, plus more whenever the interior light is on. However, if it has a switch to prevent condensation around the door, that's a 12v heater and could be consuming another couple of amps/hour, so check that out and disable if needed.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Great Horned Owl

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Re: Power consumption?
« Reply #11 on: December 10, 2013, 03:29:54 PM »
I have an Olympian Wave 3 mounted on an internal wall in the bedroom. I have it plumbed into the RV's propane system. There are also two larger sizes available, if you need more heat. Wave3.

These heaters will work at high altitude without a problem.
Edit: Fixed link.
« Last Edit: December 11, 2013, 07:28:04 AM by Tom »
Joel & Dorothy
Retired electronics engineer. Avid photographer, paddler & birder.
2011 Silverado 2500HD, Duramax, 4x4,crew cab, 8' bed
Palomino Puma 253-FBS  27' 5th wheel
1994 19' Class B Horizon / Chevy

Marsha/CA

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Re: Power consumption?
« Reply #12 on: December 10, 2013, 09:48:22 PM »
Joel, your Olympian wave camco "link" does not work.  Since I'm not sure where you are directing folks, I can't fix the link for you. you'll have to.

Marsha~
2017 Heartland Mallard IDM231 Travel Trailer....Small but mighty.

Great Horned Owl

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Re: Power consumption?
« Reply #13 on: December 10, 2013, 09:58:18 PM »
Joel & Dorothy
Retired electronics engineer. Avid photographer, paddler & birder.
2011 Silverado 2500HD, Duramax, 4x4,crew cab, 8' bed
Palomino Puma 253-FBS  27' 5th wheel
1994 19' Class B Horizon / Chevy

sbucks

  • Posts: 1
Re: Power consumption?
« Reply #14 on: December 11, 2013, 08:39:02 AM »
Hey Joel, i ran into the same problem trying to hunt out of an old class C for the past several years. My fix was....go to harbor freight and get their 3 panel 45 watt solar panel kit, it $149.00 and you can find 20% coupons easily. I wired it to my 2 deep cycle marine batteries and set it out behind the camper facing south. It charges all day,even if cloudy(just slower). Batteries are topped off by end of the day and hold up just fine all night with furnace set at 60 and using fridge on propane. i did this a week at a time with night time lows around between 0 and 20. never ran my portable generator the entire time. when heading back home i just pick up the panel and place it inside and lock up,  upon returning , put it back outside and run the generator for a few hours to top off  the batteries and all was good for another week. I also replaced my inside bulbs with LED to save power. Works like a champ!!!
Buck