Furnace and battery

[John_Hammond]

We have a 5 year old 30' Rockwood trailer that we often use dry camping at a local county park that can get cold at night. We have two 6 volt batteries and a solar charger. Before we leave home I have both batteries fully charged. While dry camping we use our solar charger and are careful about our use of electricity. We use lanterns for lights, don't use the trailer's stereo, but never-the-less in the middle of the night when I'd rather be sleeping the low batter alarm buzzer goes off just after the furnace begins to work. This can happen even on our first evening out. When I turn off the furnace the reading on our control panel indicates there is plenty of battery power left. What could possible be going on to cause this problem? Anybody out there have an idea?

[maillemaker]

But first, there is something amis if you can't make it through the night. And you mention a alarm going off, what is the alarm? normally there is nothing in the trailer that will alarm at low voltage.

Like BP said above, my propane/CO detector that is hard-wired will start making alarm sounds if the voltage goes low.

I also have 2 battery-powered CO detectors, one in each sleeping area. With a 30-year-old RV you don't take chances.

Steve

[ktmrfs]

BFL13 wrote:
"I doubt you’d find a TV anything less than 20+ years old that doesn’t disconnect itself from the TT when the ignition is turned off. "

Fords yes, Chevs no. No isolation relay in Chevs so 7-pin #4 always hot.

GM depends. on all duramax it is always hot. On at least many year gasser's it is only on with ignition running unless you have the dual battery option. Or maybe the other way around. The manual has the info.

[bpounds]

Usually a low voltage beep will be the propane leak detector. Nothing else beeps on low voltage in our trailer.

An inexpensive LCD voltage meter is so very useful for anyone who boondocks. I wish they were standard equipment right there in the trailer control panel. But it is super easy to add one yourself. Get one that will read in hundredths of a volt, 12.xx. Wouldn't you like to see what voltage is setting off the low volts warning, without going out in your skivvies, digging out a meter, and opening the battery compartment?

[BFL13]

"I doubt you’d find a TV anything less than 20+ years old that doesn’t disconnect itself from the TT when the ignition is turned off. "

Fords yes, Chevs no. No isolation relay in Chevs so 7-pin #4 always hot.

[JaxDad]

ktmrfs wrote:

John Hammond wrote:
Here are a few of the recommendations I've received regarding running out of power when dry camping and running the furnace on battery power: Please comment on what you think of these ideas:
1) Keep the overnight temperature set lower.
2) Charge the batteries during the day by running the truck engine while the truck is connected to the trailer.
3) Leave the truck connected to the trailer at night so the truck battery can supply extra power to run the furnace.
4) Get a larger solar panel.
5) Buy two more batteries and swap them during our trips.
6) Use sleeping bags to stay warm.
7) Clean the battery terminals (done).
😎 Buy a generator to change the batteries during the day.

Anyone have any thoughts about these ideas?

John

comments:

3) yup, and in the morning truck battery is dead, trailer battery dead, and your hosed

I doubt you’d find a TV anything less than 20+ years old that doesn’t disconnect itself from the TT when the ignition is turned off.

[PaulJ2]

To find the problem the first thing to do is measure the voltage at the battery terminals while the buzzer is going off. Not at the battery monitor that may be taking it's measurements 20 ft away on too small a wire. In other words a voltage drop with furnace running setting off the buzzer prematurely. Or--is the battery actually going dead?

[BFL13]

John Hammond wrote:
Here are a few of the recommendations I've received regarding running out of power when dry camping and running the furnace on battery power: Please comment on what you think of these ideas:
1) Keep the overnight temperature set lower.
2) Charge the batteries during the day by running the truck engine while the truck is connected to the trailer.
3) Leave the truck connected to the trailer at night so the truck battery can supply extra power to run the furnace.
4) Get a larger solar panel.
5) Buy two more batteries and swap them during our trips.
6) Use sleeping bags to stay warm.
7) Clean the battery terminals (done).
😎 Buy a generator to change the batteries during the day.

Anyone have any thoughts about these ideas?

John

Yes, but unprintable. Never mind all that--have you even stuck an hydrometer in those batts yet? Gosh!

[MrWizard]

forget #3 ... bad idea, you need the truck battery to stay fully charged
#4 is good ... more solar is always better
#8 is good ... generator is great, the sun doesn't always shine, gonna get some cloudy or rainy days

[ktmrfs]

John Hammond wrote:
Here are a few of the recommendations I've received regarding running out of power when dry camping and running the furnace on battery power: Please comment on what you think of these ideas:
1) Keep the overnight temperature set lower.
2) Charge the batteries during the day by running the truck engine while the truck is connected to the trailer.
3) Leave the truck connected to the trailer at night so the truck battery can supply extra power to run the furnace.
4) Get a larger solar panel.
5) Buy two more batteries and swap them during our trips.
6) Use sleeping bags to stay warm.
7) Clean the battery terminals (done).
😎 Buy a generator to change the batteries during the day.

Anyone have any thoughts about these ideas?

John

comments:
1) what we do,sleep under a quilt. Furnace cycling wakes us up, but you will still need battery in the morning
2) given the way alternators work along with the long run to the trailer, you'd likely need to run the truck all day long
3) yup, and in the morning truck battery is dead, trailer battery dead, and your hosed
4) you'd need more solar and what do you do when it is not sunny
5) one battery set should get your through at least 1 day, then a generator and a GOOD converter (not the likely WFCO) and in 2hrs or so your at 85% SOC and good to go. WFCO would mean running the generator almost all day, seldom do they go into bulk charge mode.
😎 even with lots of solar, there are times when sun doesn't shine and in the end you need a generator. Get a quite 2000W generator.

But first, there is something amis if you can't make it through the night. And you mention a alarm going off, what is the alarm? normally there is nothing in the trailer that will alarm at low voltage.

and with the alarm going off does the furnace still put out hot air?

[bpounds]

John Hammond wrote:
Here are a few of the recommendations I've received regarding running out of power when dry camping and running the furnace on battery power: Please comment on what you think of these ideas:
1) Keep the overnight temperature set lower.
2) Charge the batteries during the day by running the truck engine while the truck is connected to the trailer.
3) Leave the truck connected to the trailer at night so the truck battery can supply extra power to run the furnace.
4) Get a larger solar panel.
5) Buy two more batteries and swap them during our trips.
6) Use sleeping bags to stay warm.
7) Clean the battery terminals (done).
😎 Buy a generator to change the batteries during the day.

Anyone have any thoughts about these ideas?

John

1) We run it at the lowest temp the t-stat will go, which is about 55°. Good sleeping weather in our opinion, and if it is above that outside, we wouldn't run the heater at all.

2) Works a bit, but a very inefficient way to charge trailer batteries. A generator does a much faster job of it.

3) First, that won't work unless you have a GM truck. Both Ram and Ford disconnect the trailer plug when the engine isn't running. And on the GM, you may not get your truck started the next morning (been there). I've seen people running their truck all night for this very reason, when they found themselves cold and unprepared. Fortunately, most gas trucks idle very quietly. And the diesel owners are apparently a little more savy about camping.

All the other points have merit.

[John_Hammond]

Here are a few of the recommendations I've received regarding running out of power when dry camping and running the furnace on battery power: Please comment on what you think of these ideas:
1) Keep the overnight temperature set lower.
2) Charge the batteries during the day by running the truck engine while the truck is connected to the trailer.
3) Leave the truck connected to the trailer at night so the truck battery can supply extra power to run the furnace.
4) Get a larger solar panel.
5) Buy two more batteries and swap them during our trips.
6) Use sleeping bags to stay warm.
7) Clean the battery terminals (done).
😎 Buy a generator to change the batteries during the day.

Anyone have any thoughts about these ideas?

John

[jkwilson]

maillemaker wrote:

Steve ... maybe I'm misreading your diagram, but what 12V Group 29 batteries are you using that have a capacity of 210 AH each?

The image is a random one I pulled off the internet to show the wiring schematic. Ignore battery specifics.

Steve

My guess is whoever drew it confused RC with AH. Most 29s are rated 210 minute RC.

[BFL13]

Doug R said something I am not sure is correct, that if the fan slowed down from too low a voltage ( he said under 12.5v!!!) the sail switch would open and the then no heat.

I have not seen that happen with much lower voltages than that, but I would wonder about a low speed setting for the fan wrt the sail switch's operation. Anyway, I can't alter the furnace fan speed.

[MrWizard]

Mine doesn't let you change fan speed for heat/furnace