Furnace without shore power

[flmgrip]

I tried to have my AS heated without shore power, but half way thru the nite the batteries were drained...

What do you recommend to make it thru the nite besides thicker bedding and more clothes?

Thanks!

[DKDarrow]

Obviously you need a NEW battery...........Actually unless you ran a whole bunch of lighting and stuff should last a couple of nights......Easily through ONE.........Good Luck......Dennis

[Airstream01]

I ran mine all night in ~15F weather with thermostat set on 65F and only drained mine to about the 5/8th mark on my display. Sounds like its time for some new batteries, or some with a greater capacity.

[moosetags]

What kind of Airstream are we talking about, with what kind of furnace, with how many batteries that are how old? Your profile shows no info.

With no information to go on, my best guess would be that your battery(batteries) are crap, and not holding a good charge. An Airstream furnace fan should be able to run the night with decent batteries.

Brian

[Mexray]

The forced air, 12 volt blower motor in your furnace is the largest Amp Hog system in your AS, due to it's extended running time while heating...

When trying to run the furnace all night in COLD or FREEZING weather, your batteries must be fully charged by an external source (generator) before retiring for the night...

As noted above, if your batteries are reduced in capacity due to age, you're fighting an uphill battle, and you just won't "make it through the night."...

[flmgrip]

sorry folks for the missing info:

09 25SS international, less than 4 months old, most of the time charged by solar, barley ever with shore power, however it seems like the voltage is not even that great (around 12.2 - 12.4) after sitting all day in the sun and system in store for a couple of days...

is my solar charger not working properly? are the (stock) batteries just bad?

thanks !

[2xS]

The furnace blower on a Suburban NT-30 draws about 4.5 Amperes.

Your solar charger (let's assume) is 100W.

BEST CASE SCENARIO:

I (current) = P (power) / V (voltage)

In this case and with my assumption of your solar panels, your battery would be charging at:
I = 100W / 12V
I = 8.333 A
...during daylight... which happens to be approx. 10 hours. This would give you about 83.33A/h available to draw from.

If you never plug in, then you're relying solely on the solar to charge your battery. And if you're running the furnace while you sleep (let's assume 8 hours), then 4.5A/h is used to power your furnace.
4.5A/h*8hours = 36A

In this example, your furnace will be utilizing about half of your daily charge. BUT, you will never achieve the best case scenario specs from your solar panels in the winter. AND this example also didn't take into account any other 12VDC appliances being on like water pumps, exhaust fans, or lighting which will obviously make it drain much faster...

Consider alternative charging sources... like a gasoline powered generator, a wind turbine, love, or the 120VAC socket of your neighbors house.

[Mexray]

This is simple, at 12.2 volts, you only have about 1/2 charge in your batteries, and won't stand up to running the heate blower overnight - as you've experienced.

You'll need to charge your batteries fully before more extended use. If you are constantly running in the 12.2 volt range, the batteries will begin to sulfate due to undercharge and lose capacity.

Recharging fully after use is the only way to assure long battery life.

Once your batteries are again fully charged, the solar will be able to keep them topped off - recharging via solar when the batteries are only 1/2 charged will take forever- or at least several days if there's no load on the batteries...

Ray

[jnerges]

Originally Posted by flmgrip

I tried to have my AS heated without shore power, but half way thru the nite the batteries were drained...

What do you recommend to make it thru the nite besides thicker bedding and more clothes?

Thanks!

This same thing happened to us. We were on Orcas Island, Boondocking. Plenty of propane so what could go wrong, right? Well the propane alarm went off, not that there was a leak but there was not enough power to sustain the alarm which will cause it to honk. Like a low battery on a smoke detector. I went out and changed batteries the next day, spent the day charing off the Honda 2000 and it was fine the next night.

[Jammer]

Long ago, on our first RVing trip, in a rented trailer, we ran into this while boondocking in northern Minnesota on a cold, late September night. The trailer only had one battery in it and being a rental unit it had suffered a hard life. Ended up running off the TV battery for a while and idling the engine a little.

I've since come to the conclusion that a serious winter sleeping bag for each person is the best answer for boondocking. The furnace runs a lot less at 45 (maybe not at all depending on temperature and wind) than 70 and unless it's well below freezing out you still shouldn't have trouble with lines freezing. I have an old North Face sleeping bag that's supposed to be rated to -15 but in practice is quite comfortable down to 20 or so when I sleep outside. Then I turn up the furnace while having morning coffee.

In RVs the furnace has to be compact and so tradeoffs are made and they end up being inefficient and require a fan. There are non-electric vented heaters out there but they require a lot of space and a vertical vent pipe. Not sure I'd want one in a TT.

[wahoonc]

Originally Posted by Jammer

Long ago, on our first RVing trip, in a rented trailer, we ran into this while boondocking in northern Minnesota on a cold, late September night. The trailer only had one battery in it and being a rental unit it had suffered a hard life. Ended up running off the TV battery for a while and idling the engine a little.

I've since come to the conclusion that a serious winter sleeping bag for each person is the best answer for boondocking. The furnace runs a lot less at 45 (maybe not at all depending on temperature and wind) than 70 and unless it's well below freezing out you still shouldn't have trouble with lines freezing. I have an old North Face sleeping bag that's supposed to be rated to -15 but in practice is quite comfortable down to 20 or so when I sleep outside. Then I turn up the furnace while having morning coffee.

In RVs the furnace has to be compact and so tradeoffs are made and they end up being inefficient and require a fan. There are non-electric vented heaters out there but they require a lot of space and a vertical vent pipe. Not sure I'd want one in a TT.

They also have the Catalytic heaters that do not require venting.

On many Airstreams the holding tanks are heated by the forced air furnace so having them operational may be necessary in sub freezing conditions to keep the tanks from solidifying. FWIW that is the way my 1975 is set up, as part of my rebuild I am installing 12 volt tank heating system as a backup.

My recommendation is at the very least to have a small generator along to provide power in case you end up boondocking for an extended period due to adverse weather. I use a Honda 2000iA. I have two that can be paired up to provide power for my AC in the summer. In the winter months I will keep one with me for backup power, it has more than enough power to keep the furnace running and the batteries topped up. It saved us one weekend when an unexpected ice storm hit, the campground we were in lost power, and the road in was completed blocked by downed power lines and trees. It took a couple of days for them to get it cleared out so we could leave. If not for the generator we would have been cold and in the dark pretty quick.

We also keep the furnace on a very low setting and use the cat heater for direct warmth. Down comforters and flannel sheets on the bed.

Aaron

[DaveFL]

Originally Posted by 2xS

...
...during daylight... which happens to be approx. 10 hours. This would give you about 83.33A/h available to draw from.

If you never plug in, then you're relying solely on the solar to charge your battery. And if you're running the furnace while you sleep (let's assume 8 hours), then 4.5A/h is used to power your furnace.
4.5A/h*8hours = 36A

In this example, your furnace will be utilizing about half of your daily .

Two things not quite right here, assuming 8 hrs charge, I have found doesn't happen when it is needed, between clouds and trees covering collector cut this in half or double the collector capacity. While sleeping 8 hrs, furnace cycles and the fan with it so on time is less than the 36A.

Has anyone tried the resistor trick mentioned for the stove vent fan to reduce fan speed and power consumption? I used the resistor on the vent fan and it made an unbearable noise to a livable level.

[Lumatic]

Originally Posted by flmgrip

I tried to have my AS heated without shore power, but half way thru the nite the batteries were drained...

What do you recommend to make it thru the nite besides thicker bedding and more clothes?

Thanks!

Formulas are not my favorite even when I'm 100%. Now with the flu I can't deal. How about nice warm bodies? Like a 3 dog night? and a bottle of Jaegermeister.

[flmgrip]

thank you!

I think my solar panel is 110w... So with all the math beeing done something is not right with my batteries...

My system has been off for at least a week and I stopped by during daylight hours (solar charging), as soon as I turned on the lights the voltage dropped from maybe 13 to 12.2 ...

And I had the AS out recently and was plugged into shore, once unplugged it seemed the voltage dropped...

Did I ruin my batteries by 'deep discharging' ? Or do the stock batteries just suck and I should get some better replacements? What would u recommend ?


Thanks!

Originally Posted by 2xS

The furnace blower on a Suburban NT-30 draws about 4.5 Amperes.

Your solar charger (let's assume) is 100W.

BEST CASE SCENARIO:

I (current) = P (power) / V (voltage)

In this case and with my assumption of your solar panels, your battery would be charging at:
I = 100W / 12V
I = 8.333 A
...during daylight... which happens to be approx. 10 hours. This would give you about 83.33A/h available to draw from.

If you never plug in, then you're relying solely on the solar to charge your battery. And if you're running the furnace while you sleep (let's assume 8 hours), then 4.5A/h is used to power your furnace.
4.5A/h*8hours = 36A

In this example, your furnace will be utilizing about half of your daily charge. BUT, you will never achieve the best case scenario specs from your solar panels in the winter. AND this example also didn't take into account any other 12VDC appliances being on like water pumps, exhaust fans, or lighting which will obviously make it drain much faster...

Consider alternative charging sources... like a gasoline powered generator, a wind turbine, love, or the 120VAC socket of your neighbors house.

[Airstream01]

Have you checked the water level in the batteries recently? If not, you need to.

[3 Dog Nite]

Yes Lumatic, there are other heat sources. A 3 dog night can make for a night with little sleep. It makes one long for a larger bed.

Ricky

[wahoonc]

Originally Posted by flmgrip

thank you!

I think my solar panel is 110w... So with all the math beeing done something is not right with my batteries...

My system has been off for at least a week and I stopped by during daylight hours (solar charging), as soon as I turned on the lights the voltage dropped from maybe 13 to 12.2 ...

And I had the AS out recently and was plugged into shore, once unplugged it seemed the voltage dropped...

Did I ruin my batteries by 'deep discharging' ? Or do the stock batteries just suck and I should get some better replacements? What would u recommend ?


Thanks!

I would find out:

1. Number of batteries
2. Size of batteries
3. Age of batteries
4. Type of batteries

Also if you have a multiple battery system, a bad battery can pull down a good battery. FWIW I would consider replacing all of them if they are the same age and one is bad. This primarily applies to batteries with some age on them.

Then go from there. There are several different schools of thought on RV batteries. My preference is the Optima Blue top.

Aaron

[flmgrip]

I will check water level tomorrow and anwser the other questions too !

[flmgrip]

It's two megatron marine deep cycle, STM-24 550 cca 690, I don't know the age, but I purchased the trailer new about 5 months ago...

I checked the fluids, what is considered the right level?

Topped off or a little below that?

I hole was way low on water, all others seemed fine.

What's the best way to fill the battery and with what ?

Thanks!

[munimula]

fill each of the holes to the top with distilled water only. can be bought at most supermarkets and drug stores. careful not to overfill. that water coming out of the battery is nasty. it will burn anything it comes in contact with. something to do with sulfuric acid.