Running furnace off Batteries for extended time?

[LJ-TJ]

Batteries and Furnace. I guest the question is how can I run the Furnace when boon docking for between 8 and 16 hours with out a generator. Hm?

[DonD]

Lots of variables, how many amps does the blower use? How many amps batteries have. Mine uses less than the manufacturer shows per a VOM and with my 500 plus amp battery bank, I don't have any trouble.

[LJ-TJ]

As near as I can gather from what I'm reading is if I buy a pair of Trojan T-? 6 Volts and put them together they should run my furnace and all my electrics within reason for the weekend. I just got the old furnace in my 75 Winnebago. Run a few lights and maybe the flat screen for a few hours.

[DaveVA78Chieftain]

Example of how to esitimate usage

Device        Number     Rating          Daily Hrs       Daily Total
                                 in amps           Used          In Amp-Hrs
Lights               8    X      1.5       X       0.5       =        6
Stereo              1            2.0                4.0                 8
Water Pump     1            4.0                0.25               1
DC TV               1            5.0                4.0                 20

Minimum Daily DC Total                                            35 Amp-hr

Furnace           1            7.0                3.0                 21

Maximum Daily DC Total                                           56 Amp-hr

You should never deplete a battery lower than 50% so I would have at least 140AH battery bank (safety margin).  200AH would be preferred for this case.
That is how you determine your daily needs.

Note: Variable usage for appliances like a furnace that cycles on and off.
Number of hours turned ON = 24.  % of time ON per hour 25%.  24 X 25% = 6 Amp-hrs
% ON depends on outside temp and heat loss of rig.

Dave

[Oz]

I was just about to say the same thing, but Dave beat me to it...  :)rotflmao

[DaveVA78Chieftain]

Honestly, that is from the book Managing 12 Volts by Harold Barre

Amazon

Dave

[moonlitcoyote]

best solution is a catalytic heater I installed a Wave 6 and it works fabulously. http://www.adventurerv.net/olympian-wave-catalytic-safety-heater-p-1681.html?utm_campaign=partsfeed_ppc&utm_medium=cpc&utm_source=Froogle&gclid=CLz6lL-QtL4CFW4R7AodUgIAIQ

[DonD]

I've boondocked in the winter up north and just run the genny for 2-3 hours in the evening works for my set up. I watch the TV at gen time if I get reception or see a vid. Never have come close to flat house batts. I am gone all day 4 wheeling so no furnace draw then.

[Froggy1936]

Minor detail, This product cannot be shipped to Canada !  TJ got any friends just this side of the border ?    i??  Frank

[ClydesdaleKevin]

We've also got the Wave 8 Catalytic heater...and they work AWESOME!!!

Kev

[LJ-TJ]

Ok I know I'm a pain in the bum BUT just found a disconnected wire in my converter. Think I figured out where it went to so hooked it up. Just going to fire up the rig and see if it made any differance any were. Question I have 3 deep cycle RV/Marine batteries that read 12 volts on my test meter. Are they any good or should I scrap them or can they be brought back to read 13 to 14 volts? Hm?

[DaveVA78Chieftain]

12.0VDC = 50% charge



Fully charged, at rest is 12.6VDC

To recharge a 50% battery a typical battery charger will be up around 14.1 to 14.5VDC while charging in order to have enough force to push energy back into the battery.  Once charged, the battery is seeing a residual 13-14VDC surface charge from the higher charging voltage.  You have to remove the "surface charge" to get a true reading of the battery condition.  You have to apply a load like several lights for a few minutes (headlights on a car battery).  Once the surface charge is removed, the battery voltage should read 12.6VDC.

Dave

[ibdilbert01]

I think the best bang for the buck is a pair of golf cart batteries.      While in TN last year, my converter died and we had no way to charge the batteries, we went the weekend using the furnace, no issues.  (weather was about 50 degrees)   I will say on Sunday the lights were dim but seeing how I  consistently deplete my batteries till they have no charge and they are 6 years old, I am sure they are not running up to their full capacity.