Running Furnace on Battery

T@Buhura · January 2016

Does anyone have experience running their furnace on 2006/2007 T@Bs off battery? I'm curious to know how well/long it can run without killing the battery.

We went snow camping a few weekends ago and while it was a lot of fun, I was afraid to run the furnace off battery for too long for worry of waking up to an unrecoverable battery. Thankfully a neighbor had a little generator that he let us plug into to run our furnace the first night and we enjoyed some warmth. Then the second night no such luck. He was still there and we got to plug into his little Honda generator but the furnace wouldn't come on (heat or blower). The battery was fine, well above 12v following the weekend. The only thing we kept running over the 3 days was the fridge on propane - which was completely unnecessary as it was working more as an ice box; although the side perk was that by running the propane fridge it seemed to keep the front of the T@B warm enough to keep the waterline to the pump and sink from freezing.

KyBawpaw · February 2016

That's a question I've mulled over myself. I'd say that battery power is the only way to use the furnace since if you have shore power or generator then use a small ceramic space heater. Mine works great! No propane OR battery drain. Once I did have to use my furnace overnight on shore power in Brown County Indiana after dropping and breaking my ceramic heater at bedtime. Picked up a new one next day at Wally's. The answer depends also on how cold it is outside. The colder it is the more often the burner and blower will kick on, just like home. My instincts tell me it should make it thru a fairly cold night with reasonable battery juice left over. That's what it was made for, huh?

IMHO with limited experience behind it.

jkjenn · February 2016

KyBawpaw said:

That's a question I've mulled over myself. I'd say that battery power is the only way to use the furnace since if you have shore power or generator then use a small ceramic space heater. Mine works great! No propane OR battery drain. Once I did have to use my furnace overnight on shore power in Brown County Indiana after dropping and breaking my ceramic heater at bedtime. Picked up a new one next day at Wally's. The answer depends also on how cold it is outside. The colder it is the more often the burner and blower will kick on, just like home. My instincts tell me it should make it thru a fairly cold night with reasonable battery juice left over. That's what it was made for, huh? IMHO with limited experience behind it.

Don't you have an Alde? If so, they run very nicely on LP. It only uses a very tiny amount of battery.

clkeller · February 2016

I have a solar panel and I can run fridge and furnace for about a week and my battery don't die

Mercator · February 2016

Last winter I was planning a trip from Toronto to Key West and was going to be boon docking (Walmart) for several nights on the way down and the way back. The temperatures were around 20 ° F during the nights I used the furnace on battery power.

The T@B manual that I found showed a fairly high current draw for the Atwood furnace- 10-12 amps. I too was worried that it might not last overnight so I had a much larger - group 31 battery installed. However, I found the amp draw from the T@B manual to be completed erroneous and misleading. As it turned out I could have managed with the smaller group 24 battery that was already in the trailer.

The Atwood manual (attached) shows the current draw to be 3.4 amps. I'm sorry I don't have the exact numbers I used, (I have an ammeter wired into the system so I could monitor the usage), but the furnace didn't run continuously, so the nightly amperage draw was even lower.

As for propane, a twenty pound bottle contains 430,000 btu and should last a long time. I think the Atwood furnace is the 7912 which uses 12,000 but/hr. If the furnace were running continuously (which mine never did) it would last about 35 hours.

Mercator · February 2016

T@Buhura said:

<snip>... Then the second night no such luck. He was still there and we got to plug into his little Honda generator but the furnace wouldn't come on (heat or blower). The battery was fine, well above 12v following the weekend. ...

If you had lights and fridge (it needs some battery power even on propane to keep the solenoid controlled valve open) it might have been the furnace fuse was blown. Have you checked it?

T@Buhura · February 2016

Mercator said:

T@Buhura said:

<snip>... Then the second night no such luck. He was still there and we got to plug into his little Honda generator but the furnace wouldn't come on (heat or blower). The battery was fine, well above 12v following the weekend. ...

If you had lights and fridge (it needs some battery power even on propane to keep the solenoid controlled valve open) it might have been the furnace fuse was blown. Have you checked it?

Actually, it's funny you make that comment. I had tried to troubleshoot the second night and went through the converter and checked the fuses. One thing I noticed is on one of the fuses (maybe 2) of the 4, When I pulled the fuse, the little green indicator light on the panel didn't light. The fuses looked fine, but now I'm wondering if the converter may have not been since the blown fuse/open circuit indicator didn't light next to the fuse socket. That would be great if that's the case as it's a new converter (less than a year old) and should be under warranty. Still, I'm not terribly excited about how the furnace (yes I have the Atwood, not sure which model exactly) sits under the bench. It doesn't seem to be well secured so I put extra fasteners on it to tighten it down.

I'm waiting to hear from the dealer to see what could be wrong. I dropped it off too to have them put diamond plating on the front (a la Outback) to spruce it up after some road rash.

Also on the battery answer, that's great that it's only 3.4Amps. Certainly a lot less than the Northern Breeze fan which can really suck down the battery. I will want to put on ampmeter on the Atwood to get a good read on it. BTW, I'm reading the 3.4A in the Atwood manual as 3.4Amp Hours... It doesn't clarify it as Amp Hours but is it safe to assume as such?

Mercator · February 2016

T@Buhura said:

<snip> BTW, I'm reading the 3.4A in the Atwood manual as 3.4Amp Hours... It doesn't clarify it as Amp Hours but is it safe to assume as such?

Yes, that would 3.4 amps per hour (amp/hours). If you have the typical group 24 battery it will have about 70-85 amp hours of capacity (when new). My Group 31 battery has about 108 amp hours.

Mercator · February 2016

I ran the Atwood furnace today and it showed a draw of 3.5 amps.

BTW, when I first turned the furnace on I had forgotten to turn on the propane. After a few seconds the furnace stopped. I wentt out and opened the propane valve, but the furnace wouldn't start until I turned off the thermostat and turned it on again.

T@Buhura · February 2016

Mercator said:

I ran the Atwood furnace today and it showed a draw of 3.5 amps.

BTW, when I first turned the furnace on I had forgotten to turn on the propane. After a few seconds the furnace stopped. I wt out and opened the propane valve, but the furnace wouldn't start until I turned off the thermostat and turned it on again.

That's good to know. In our case I had the propane on from when we arrived to when we left (fridge and stove burning too). But before we left for the weekend, I had tested it in the driveway and noticed that it didn't want to turn on initially until I had let gas flush the air out of the system by lighting the stove. It's when I noticed it was purging air from the lines since it took a long time before the burner got gas and lit.

KyBawpaw · February 2016

@jkjenn Don't have the Alde. I have an Atwood 7912 propane furnace. It heats the T@B quick and easy. I have a early 2014 T@B Max S. Bought it used. Guess the Alde was an option or mid run upgrade.

T@Buhura · February 2016

Mystery solved on why the furnace didn't come on the second night - if I had only known! It has its own breaker and it had tripped thanks to the spiky little Honda. Ended up paying a "diagnostic" charge for that but they say it's good. On the upside also got our faithful T@B spruced up with diamond plating.

jkjenn · February 2016

T@Buhura said:

Mystery solved on why the furnace didn't come on the second night - if I had only known! It has its own breaker and it had tripped thanks to the spiky little Honda. Ended up paying a "diagnostic" charge for that but they say it's good. On the upside also got our faithful T@B spruced up with diamond plating.

Are you using a surge protector?

Nomad · February 2016

Hmmmm - Never had anything tripped when running my Honda - not using a surge protector when on generator, only when on campground power.

T@Buhura · February 2016

PXLated said:

Hmmmm - Never had anything tripped when running my Honda - not using a surge protector when on generator, only when on campground power.

Our neighbor who had the 2000i that let us plug into while he was using it was taxing it somehow and it would get peaky at times. What's funny is it worked fine throughout the first time and then I powered off for the night. The next morning I tried starting and nothing. It seems odd it would have tripped at the end or while not in use.

We used it this weekend and it worked great off battery and a few hours of solar (hard to keep snow off panels).

T@Buhura · February 2016

jkjenn said:

T@Buhura said:

Mystery solved on why the furnace didn't come on the second night - if I had only known! It has its own breaker and it had tripped thanks to the spiky little Honda. Ended up paying a "diagnostic" charge for that but they say it's good. On the upside also got our faithful T@B spruced up with diamond plating.

Are you using a surge protector?

No! But our dealer recommended this:

http://www.amazon.com/TRC-44260-Amp-Circuit-Analyzer/dp/B00JYMZ8HK/ref=sr_1_sc_1?ie=UTF8&qid=1454962954&sr=8-1-spell&keywords=surgeguard+44260

Any experience with it? I know others on the board recommend the Progressive but it seems like overkill. I have 3way fridge, furnace, Radio/CD, and HAM radio.

Nomad · February 2016

I've always thought it was overkill also - but, I'm "rarely" in campgrounds with hookups. I do have a curcuit testing plug - believe it's the same thing Verna uses - that gives me an all clear before I plug the cable into it. Not really a surge or low voltage protector though.

Verna · February 2016

T@Buhura said:

jkjenn said:

T@Buhura said:

Mystery solved on why the furnace didn't come on the second night - if I had only known! It has its own breaker and it had tripped thanks to the spiky little Honda. Ended up paying a "diagnostic" charge for that but they say it's good. On the upside also got our faithful T@B spruced up with diamond plating.

Are you using a surge protector?

No! But our dealer recommended this:

http://www.amazon.com/TRC-44260-Amp-Circuit-Analyzer/dp/B00JYMZ8HK/ref=sr_1_sc_1?ie=UTF8&qid=1454962954&sr=8-1-spell&keywords=surgeguard+44260

Any experience with it? I know others on the board recommend the Progressive but it seems like overkill. I have 3way fridge, furnace, Radio/CD, and HAM radio.

That's all I have connected. I bought it last January and I've been using it faithfully when connected to electric. One of these days I'll install the built-in one, but I have other priorities right now.

Ratkity · February 2016

Yup Verna.. I have that type of "List" too. Then on top of that, I get distracted by shiny things ... wait! LOOK!

SQUIRREL!

jkjenn · February 2016

T@Buhura said:

jkjenn said:

T@Buhura said:

Mystery solved on why the furnace didn't come on the second night - if I had only known! It has its own breaker and it had tripped thanks to the spiky little Honda. Ended up paying a "diagnostic" charge for that but they say it's good. On the upside also got our faithful T@B spruced up with diamond plating.

Are you using a surge protector?

No! But our dealer recommended this:

http://www.amazon.com/TRC-44260-Amp-Circuit-Analyzer/dp/B00JYMZ8HK/ref=sr_1_sc_1?ie=UTF8&qid=1454962954&sr=8-1-spell&keywords=surgeguard+44260

Any experience with it? I know others on the board recommend the Progressive but it seems like overkill. I have 3way fridge, furnace, Radio/CD, and HAM radio.

I know it seems like overkill, but IMHO, it isn't overkill. As a matter of fact, if I could have only done one modification or addition to my T@b this would be it. You could be saving yourself from ruining your appliances - or anything you are charging and perhaps even fire. There are very few brands in any market that have not only the performance reputation and also the customer service reputation that Progressive has. I am not saying other brands on't work or that they are poor, but Progressive is the one that RVers of all varieties rave about.

A good surge protector will also protect you and your family from RV "hot skin", low and high voltage, polarity errors, and other issues from outside power sources.

Nomad · February 2016

As usual, depends on what type of camping one does - overkill for me but probably wouldn't be if I was always in campgrounds with hookups. A circuit tester works fine for the rare times I'm hooked up. But, I'm a minimalist and even more so after reading the forums and being on the the road for a considerable amount of time. There's just no end to the things you can do or add :-)

T@Buhura · February 2016

PXLated said:

As usual, depends on what type of camping one does - overkill for me but probably wouldn't be if I was always in campgrounds with hookups. A circuit tester works fine for the rare times I'm hooked up. But, I'm a minimalist and even more so after reading the forums and being on the the road for a considerable amount of time. There's just no end to the things you can do or add :-)

Agree! For example, during our trip to AK we camped 30+ nights and only plugged in 2 of those nights. I think since we've had it we only docked fewer than 5 times where we've actual camped or as part of testing at home. I love our Bosch solar panels!

Perhaps the route I might go is the tester with spike/surge protection like the dealer recommended for the few times we might use it and if it will actually have benefits/be functional. It was certainly a surprise to learn the furnace had its own separate breaker - and harder to get to than the one on the converter.

mash2 · February 2016

I picked up a TRC 34730 surge protector (with voltage control) a while back for really cheap (70% off) and it has worked fine for the few times I've hooked up -- not my normal situation. I got it because it was a great deal for the price and was good for the occasional hookup. (Just sits in the back corner of the bottom drawer).

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