Furnace murders the batteries

[Lance M]

The literature for your trailer shows it has a 25,000 BTU Atwood Hydroflame IV 8525 which is rated at 7.6 amps-91 Watts. Two group 27 batteries fully charged should give you 100a/h of use at 50% depth of discharge. If you ran the furnace for 10 hours and it was on half the time it should only take 38 a/h of battery.
How many amps does the furnace draw when operating?

[JCWDCW]

We always had a problem with killing the single battery using a Suburban furnace. I suspect the previous owners did too. They installed a catalytic heater on the end of counter beside the door. Because it is in the living area, it keeps things cosy but you still need the extra blankets. I also worry about being overcome by CO. Keeping the roof vents open and a window nearby in the kitchen area is adequate. The catalytic heater does have specifications for how much vent area is required. The CO monitor should sound more than early enough to keep you safe.
JCW

[Minipad]

The furnace is a big draw (mine is about 8.0 ah) and will wack the batteries. Unfortunately, when you need to run the furnace, your batteries are also in low ambient temps which drastically reduces their efficiency. You might notice your solar system seems to bring them back pretty quick but part of that is because your outside ambient temps are also increasing. If you are concerned about the safety of an additional heater inside, you might throw a blanket over the battery box (all outside the trailer) and put a heater underneath to actually keep the batteries warmer. (Obviously you don't want to have a gust of wind blow your blanket into the heater and start a fire out there. So, common sense is in order.) If you do put a heater inside to supplement or replace the furnace use, just remember that you have lost heat to the basement and if the temps are well below freezing, you might freeze pipes below.

I deal with the same problem in the mountains all summer long. Cold nights and warm days. It leads one to believe that the batteries are the problem but maybe the greatest issue is the batteries are just cold. My solution has been to add a vented tool box in which I have put a battery. (Actually I have two of these.) On the outside of the tool box, I have wired a typical tow vehicle umbilical plug receiver. I plug my trailer into one of these boxes at night and with the temps you are experiencing, My batteries (now 3 total) stay above 70% overnight. The tool boxes are recharged during the day as they travel in the back of my truck which has a separate solar system to the one on the trailer. If I am staying put, I leave the toolbox plugged in and both solar systems recharge all the batteries. One of these days, I am going to move my batteries inside the coach to avoid the problem. Tesla automotive has discovered that by heating their batteries in cold ambient conditions, the amperage they loose to the heating system, is less than the gain from the increased battery efficiency of warmer batteries.

[BoldAdventure]

Originally Posted by Minipad

The furnace is a big draw (mine is about 8.0 ah) and will wack the batteries. Unfortunately, when you need to run the furnace, your batteries are also in low ambient temps which drastically reduces their efficiency. You might notice your solar system seems to bring them back pretty quick but part of that is because your outside ambient temps are also increasing......

....Tesla automotive has discovered that by heating their batteries in cold ambient conditions, the amperage they loose to the heating system, is less than the gain from the increased battery efficiency of warmer batteries.

Very interesting, I had thought about the temp thing. Which might be part of whats going on. The only other things I leave running at night are Wilson Booster and Mifi. We usually charge our iPhones off a portable battery at night and recharge that battery during the day.

I have some extra reflectix, I wonder if I could line the battery box with that. Just need to insure that it's not conductive.

[Al and Missy]

Mike,

Either I am missing something or something else is going on. If your furnace was running 100% for 8 hours that is only 64-72 Ah vs. 200Ah capacity. It's probably more like 50%. I know mine runs 50% or less at around 40 outside. Now if you got little or no solar for an entire day and actually used 64Ah two nights, that could make sense, but I'm not clear on if your problem happens after one night or two with poor sun conditions.

400W of solar with 4 equivalent solar hours should give you 130Ah or so, more than enough to run your furnace. Either your solar system isn't putting out, you have some parasitic loads, or your batteries are bad. You need to get an ammeter (if your solar system doesn't have one) and measure the current going into the batteries when you have good sun and disconnect the solar panels and measure the current coming out under the same conditions as you operate it at night. Assuming it is more than you think, start disconnecting and turning off stuff until you have found all the loads.

Here are some curves for temperature effects. It doesn't appear that 40F is much of a problem, if they are correct.

https://www.google.com/search?q=lead...9qs-UNyVhQk%3D


Al

[idroba]

I would concur with Al and Missy's response above. Something else is going on to either draw down the batteries, or they are not fully recharging. Of course even new batteries have been known to be defective from the get go.

Your furnace fan is not taking down those batteries that much. So, more investigation is needed, hopefully with some measured amp draw numbers.

BTW, the MiFi and the Wilson booster are quite minor loads.

[Gearheart]

Batteries that have been drawn down below 11 volts are catastrophically discharged and will likely never take a full charge again. Your capacity may have been compromised by such an event. As a scouter who has slept outside in sub zero temps and been warm thanks to a decent sleeping bag, I would recommend improving your sleep system rather than wasting energy keeping the trailer comfy warm. A load test of the batteries is in order.

[ghaynes755]

Bold you said it kills the batteries but you did an NEI (not enough information). What does the capacity and voltage show before you go to bed and what is it in the morning. How many AH were used overnight? You didn't say which IPN but the IPN Pro has that type of information. If your batteries are the typical 105ah x 2 and you used 8ah/hr for 10 hrs then you have hit them pretty hard. And full charging usually starts about 10am to 3pm so if you start the morning with only 25ah available before the charging kicks in the yep, they are pretty well driven down to min levels. Throw in a cloudy day and out comes the Honda so that you can recover.

Maybe time for more/bigger/better batteries and/or more solar panels .

[BoldAdventure]

Never mind, forget I asked, I'll run the experiment again next time it gets cold with more measurements.

I have the IPN Pro Remote, also BlueSky charge controller. Up in the cabinet over the dinette, I installed a few outlets and a voltage meter. It usually displays a lower number than what the IPN Pro is reading, since that on is coming straight of the battery. Maybe I just got confused since I'm posting this a day later and I had looked at the meter in the cabinet and freaked out.

And now that I think about it, I wonder if I left the inverter on all night. That would of meant my computer and monitor were in standby all night long.

And when it's cloudy, I run the generator. Actually Sunday & Monday were the first two days I used it most of the day. But turned it off around 8pm. So I know I had full charge when I went to sleep.

[slowmover]

Originally Posted by Top

<insert CPT Obvious photo here>





If you only need a furnace for when the overnight temps are 35-50, 9,000 BTUs is more than enough. If you want, you can add another for 18,000 BTUs at 4 amps. The fact that they are a forced air furnace that can be added on in the space below the floor and they only draw 2 amps make them appealing to me. There is no need to waste BTUs heating the holding tanks in temps above freezing. I like to boondock in the winter in Texas, so this would be an ideal furnace to replace the big, old, noisy, energy hog 30,000 BTU Suburban furnace.

Except when a blue norther comes roaring down the Plains. Just as summer sun is a problem, so is the wind in a winter cold front.

[slowmover]

Originally Posted by BoldAdventure

Anyone know about the Olympian Wave 3 catalytic heater? Perhaps plumbed into the oven propane line.

Probably the most popular one. But there is another (name escapes me) that draws external combustion air.

See posts by 2Airishuman for an older and long discussion.

The catalysts on these things can deteriorate rather fast.

[pmclemore]

I have an Olympian Wave 8 installed in my rig and I love it. And so does Page. There is nothing like having an instant warm spot whenever you need one.

I looked into the Cat heater described by 2Air before I bought the Olympian. I spoke to the owner/manufacturer and decided that I would prefer one factory built rather than one handmade by some guy. The Cat is probably a superior unit, but I just didn't go that way.

Pat

[field & stream]

I am late to this discussion, but I agree that it seems something else (besides the furnace) is contributing to the problem.

We went to 6v golf kart batteries to help with the problem of how much the furnace draws down batteries, and are happy we did. In my opinion, you have more than enough solar (we have 200w), primarily you need more storage and to figure out what else is going on.

[ROBERT CROSS]

Two grp27 Lifelines, one Honda 2000i, and a pair of 15000btu Duofold's.

Bob

[BoldAdventure]

Originally Posted by ROBERT CROSS

Two grp27 Lifelines, one Honda 2000i, and a pair of 15000btu Duofold's.

Bob

I have two grp 27's already and the Honda eu2000i (see above photos).

They don't make the underwear for babies. One of my girls is 5 months, can't pile huge blankets on her, not safe when sleeping. Sids and suffocation risk.

We ran the furnace last night, batteries were at 12.5 last night when the sun went down and no additional charge was flowing into the batteries.

Woke up this morning to 12.3 voltage. I think I looked at the wrong meter the other day. I'll keep seeing what happens.

We're moving to different batteries in a couple months.

[Meeks]

I have wondered if solar, assuming there is enough sunlight and that the solar system is sized appropriately for the circumstances, would keep up with furnace use draining the batteries during cold snaps. Only time will tell for each of us, of course.

I have been quite interested in the vent free propane heaters. There are many folks who are deathly afraid of them because....they fear dying. Reasonable enough . From all that I've read, from the one sad RV story where folks did die (snow fell during the evening and blocked the window(s?) providing fresh air into the RV) to many full-time boondockers who use these heaters regularly, it seems like a good way to go for some folks. Some use them only during the day when they can monitor the air flow and some use them at night. All speak of making sure to leave both a window and roof vent partially open for air flow as oxygen is something we all need to live . And what some full-timers say to the "naysayers" is we already have propane and carbon monoxide detectors in our Airstreams (at least the newer ones) and the heaters themselves come with their own carbon monoxide detectors so there is double coverage for monitoring.

These heaters, as someone else mentioned, do not obviously heat the water and waste tanks below the trailer floor so when the temps drop below freezing one needs to run the Airstream provided furnace.

This article is one of the best I've found (thanks to those that took the time to write it!) with links to more learning about the different types of heaters, etc.: RV Heater: How to Install a Vent-Free Propane Heater in an RV

I sure would love to hear from more Airstreamers, who are using these types of heaters, to learn from them. I'm still on the fence as to whether to install one some day. I'll start with more solar and see how and where our travels bring us as the years go on.

As an aside, BoldAdventure, I've appreciated many of your posts. And you're going to love your new batteries that aren't Marine-based (if I understand correctly what you're currently using) when you get them.

[BoldAdventure]

Well everyone was right, I totally have shot batteries, not sure how that happened. Been checking the water levels, and everything. But they are discharging way to fast. Probably what I get for using the marine/rv costco batteries. Lesson learned.

[TouringDan]

Originally Posted by Top

<insert CPT Obvious photo here>


If you only need a furnace for when the overnight temps are 35-50, 9,000 BTUs is more than enough. If you want, you can add another for 18,000 BTUs at 4 amps. The fact that they are a forced air furnace that can be added on in the space below the floor and they only draw 2 amps make them appealing to me. There is no need to waste BTUs heating the holding tanks in temps above freezing. I like to boondock in the winter in Texas, so this would be an ideal furnace to replace the big, old, noisy, energy hog 30,000 BTU Suburban furnace.

I used similar logic when I decided to replace my 20,000 btu furnace in my 66 Tradewind. I looked at the furnace that you referred to but decided on an Atwood Everest Star #8012, 12,000 btu capacity that should fit into the original space. The blower draw is only 1.8 amps. It was less than $500. I have not installed it yet, but will before cold weather hits.

I am sure that 12,000 btu will be more than adequate to keep us warm. I suspect that all our cold weather camping will be in above freezing temperatures.

Dan

[Slats]

Originally Posted by Top

I installed an Olympian in a '66 Trade Wind. The owner is very happy with it. It is the only heater in the trailer.

I would recommend you tap into the propane supply under the trailer.

I have a '66 Tradewind and am thinking about doing the same. Where in the trailer did you install it? Have any pictures?

[6PackCharlie]

I have had this problems with my Airstream. I have a diesel pickup that has 2 batteries. I plug the AS into the pickup at night (with the pigtail) and it works great. Have heat all night and recharge the batteries with my Honda generator during the day as needed. Have the 2 batteries on the AS and the two additional ones on the pickup all available to the heater. Hope this helps.