Furnace running on battery

chaslorr · 12-10-2014, 01:17 PM

How long will my battery run the furnace when not connected to electricity? Is it reasonable to assume it would power it for a night stop over, and then after a days driving and charging from the tow vehicle, power it for another night. This would be without using any other draws such as lights and such. Have Rockwood Minilite 2109S with single 12 volt battery.

Tucson Joe · 12-10-2014, 01:20 PM

I have 2 batteries and can get one night without a problem. My fiends with one battery usually have a dead one by morning.

chaslorr · 12-10-2014, 01:32 PM

Hmmm, I thought with the furnace coming on and off, and the fan being the only draw, that it would last longer than that. Maybe I am dreaming.

MtnGuy · 12-10-2014, 01:38 PM

My 1 battery will not power the furnace over night on a cold nite.

We use a Big Buddy heater when dry camping......with windows cracked open, of course.

SKnight · 12-10-2014, 01:40 PM

With one battery the furnace will pretty much kill it overnight. Two should suffice fine.

There's an easy way to find out, try it at home. Set the furnace to 50* and let it run overnight. Get up at some point through the night and check the voltage, batteries aren't very happy after being sucked below 12.00V.

As for charging it, yes it will, depending on how far you drive. The charging circuit isn't really meant to recharge a dead battery, it will top one up, but not completely charge it unless it's connected for a long time.

**dcheatwood** · 12-10-2014, 01:41 PM

I've gone several days like that dry camping. Running gen a few hours each evening to charge battery then furnace would cycle all night.
There are so many variables. 1. Outside temp. 2. Thermostat setting. 3. Size of furnace. 4. Square feet of RV to be heated. 5. Size and condition of battery. 6. Other items drawing on battery. 7. Battery charge at beginning.
But yes, it can be done if all factors at in your favor. Good luck .

rotorhead1250 · 12-10-2014, 02:51 PM

When I'm dry camping and it's cold enough for heat, I run my Yamaha 2400 gen all night long. It uses exactly $2.21 in fuel at current prices and my batteries remain fully charged. Makes me a happy camper.

Witch Doctor · 12-10-2014, 03:47 PM

Quote:

Originally Posted by rotorhead1250

When I'm dry camping and it's cold enough for heat, I run my Yamaha 2400 gen all night long. It uses exactly $2.21 in fuel at current prices and my batteries remain fully charged. Makes me a happy camper.

Well that's certainly oneway if you where boondocking and nobody around me I would do the same if I had one. Some generators are pretty loud.....

**bikendan** · 12-10-2014, 03:50 PM

Quote:

Originally Posted by rotorhead1250

When I'm dry camping and it's cold enough for heat, I run my Yamaha 2400 gen all night long. It uses exactly $2.21 in fuel at current prices and my batteries remain fully charged. Makes me a happy camper.

since dry camping is camping in a campground without hookups, what campground allows you to run the generator all nite? i've never heard of any campground that allows that.

unless you mean boondocking, which is camping in undeveloped areas, where you could do that.

to the OP, you'd be lucky to go one night on a Group 24 battery, running the furnace.
we rarely camp with any hookups so we have a dual battery setup and a Honda 2000.

and as was said, expecting your tow vehicle to recharge a depleted battery is not realistic.
one, most tow vehicles supply only a trickle charge while towing. and if the battery is dead, you'd have to drive over 12 hours probably to get it anywhere near full charge.

Witch Doctor · 12-10-2014, 03:53 PM

Quote:

Originally Posted by SKnight

With one battery the furnace will pretty much kill it overnight. Two should suffice fine.

There's an easy way to find out, try it at home. Set the furnace to 50* and let it run overnight. Get up at some point through the night and check the voltage, batteries aren't very happy after being sucked below 12.00V.

As for charging it, yes it will, depending on how far you drive. The charging circuit isn't really meant to recharge a dead battery, it will top one up, but not completely charge it unless it's connected for a long time.

That brings up a good question do you know how many amps are sent to your battery by your alternator? Always wondered that. In the Marine industry they have alternators that will put out 125 amps. For shorter engine running time on a sail boat. It also would replace the one on your TV. I have never measured it, Just wondering if you know?

rotorhead1250 · 12-10-2014, 03:54 PM

Oh yea, I should of added that about running the generator all night. Im usually in the woods. Nearest camper is a mile or five away.
I try and keep the batteries fully charged all the time.

**KyDan** · 12-10-2014, 03:56 PM

Quote:

Originally Posted by chaslorr

How long will my battery run the furnace when not connected to electricity? Is it reasonable to assume it would power it for a night stop over, and then after a days driving and charging from the tow vehicle, power it for another night. This would be without using any other draws such as lights and such. Have Rockwood Minilite 2109S with single 12 volt battery.

There are so many variables here it's very difficult to give a good answer.

First lets cut to the chaise- many folks falsely believe that they can recharge
the trailer battery by hooking up to their tow vehicle and driving.
Wrong! Since the trailer battery is so far down stream the voltage regulator in the engine charges the engine battery then cuts back
on voltage so as not to over charge the engine battery. This leaves the
trailer battery with very little charge going to it.

2nd- you might be OK for 1 night on battery with the furnace if you don't
turn the thermostat up too high. We camped several times with one
battery and were fine the first night. The 2nd nite we ran out of juice....
It also depends on how cold the nights are how big your trailer is etc.

Hope this helps!

rotorhead1250 · 12-10-2014, 04:00 PM

Dry camping/ boondocking. Sorry, thought they were the same thing. Guess I was mistaken.

Martingale · 12-10-2014, 04:27 PM

Many factors at play here, a couple of the big ones:
1. Power draw from heater - how many times it runs and how long for each run (largely a function of outside temp, thermostat setting and amount of heat loss in TT)
2. Battery capacity (and health of battery) plus other items using battery.

You could do a lot of testing and math to figure our the real numbers but folks usually just get a feeling for things after using their rigs for awhile.

All that being said, we can get 3 nights easily on a fresh Group 29 battery using the heater in our pop-up, and will go a week in Yosemite using two G29 batteries. We do carry a Yamaha 2400 genny as a back up for the week long trips - but it mostly gets used to power DD & DW's hair dryer!

**ependydad** · 12-10-2014, 04:33 PM

No clue, but I may find out if my new Group 27 battery will do it. Depends if we make it to a Camping World and if they have space available for us to park overnight. I'll end up driving 10-12 hours the next day but I expect to have electric hookups that 2nd night.

rana · 12-10-2014, 04:37 PM

Quote:

Originally Posted by rotorhead1250

When I'm dry camping and it's cold enough for heat, I run my Yamaha 2400 gen all night long. It uses exactly $2.21 in fuel at current prices and my batteries remain fully charged. Makes me a happy camper.

You are funnin us right? LOL

rana · 12-10-2014, 04:47 PM

Quote:

Originally Posted by rotorhead1250

Oh yea, I should of added that about running the generator all night. Im usually in the woods. Nearest camper is a mile or five away.
I try and keep the batteries fully charged all the time.

Ummm.. you DO realize that sound travels for miles? That out in the sticks the sound and fumes from your burning genset severely impacts the immediate wildlife patterns? Many with nocturnal tendencies... Simply the vibration can affect wildlife patterns for weeks...

That's a real good way to wake up to sugar in your genset. LOL

I don't mean to be harsh... but if you don't have the respect to conform to where you are.. you have no business being there.

I will step of my soap box...

SKnight · 12-10-2014, 04:52 PM

Quote:

Originally Posted by gljurczyk

That brings up a good question do you know how many amps are sent to your battery by your alternator? Always wondered that. In the Marine industry they have alternators that will put out 125 amps. For shorter engine running time on a sail boat. It also would replace the one on your TV. I have never measured it, Just wondering if you know?

It's not the alternator actually. The charging wire has every amp the system can provide at it's disposal, batteries, alternator and all. The limiting factor is the size of the wire. A wire will only transfer so much energy in relation to it's size. The trailer battery wire is usually 12 gauge or so, and is run through the fuse block meaning several connections which limits energy transfer also.

It will provide 10-15 amps of charging power, but when the battery has been drained 40-50 amps then that means roughly 3-4 hours to top up.

Now, and this is something I've been considering, if you ran a 0 or 2 gauge cable set back to the battery it will charge it at the full rate your alternator can provide. The alternator on my truck is 140 or 165 amps (I don't recall.) and a battery will soak that up at a probably 40-50 actual draw (Batteries can only absorb energy so fast.) so now we're charging things up in an hour or so.

I've thought about adding that type of setup as a backup plan, in case my converter fails or I'm about to travel but only an hour or so away. You can use an onboard jumpercable set that has the large spade connections such as what a wrecker uses. Leave the regular setup for every day, but if you need the big energy transfer you plug in the umbilical cord and away you go.

rana · 12-10-2014, 05:15 PM

Apologies in part.. ;-) I've just had this yahoo over on the other side of the hill doing the same thing the past 3 nights.. so my nerves are a bit frazzled. LOL

rotorhead1250 · 12-10-2014, 05:49 PM

Yarome, that's twice you've laughed at me for stating i run my generator all night. What is the problem with that? You say I have no business being in the woods? Really? Who are you to tell me where I can or can't camp? That gen runs at 53 db and a normal conversation is 60 db so your point is what? Sorry to everyone else for this but I must defend stupid remarks aimed at me.

You may also like: