Topic: Can the furnace be run without having 120VAC? (Read 6760 times) previous topic - next topic

Living in Florida, I ,so far, haven't even tried using the LP furnace for heating. But I am planning on a trip into the mountains of N Carolina next week and part of that will be boon-docking. I expect it will be getting chilly at night. I might be staying at a Harvest Host site so I won't be able to plug-in or run the genset. It isn't clear reading the owner's manual if the furnace/heater requires 120VAC to operate. I know it is controlled via the same thermostat as the AC/heat pump, but AFAIK it is otherwise a totally separate system with no blower.  My RV is currently at a storage lot so I can't test it. Will I be OK?

Yes, you should be fine. The LP furnace has a blower that is 12v so your limiting factors are how much you use the furnace, what your battery capacity is and the recharge option you have.

Yes…..I boon dock and use my furnace when needed; just don’t have it ‘cranked’ where it runs constantly. Just enough to keep the chill out and from seeing your breath! Ha!

Thanks to those who commented. I needed the furnace since it got down into the low 40's last week while boon docking in the Asheville NC area. It didn't run much - just enough to sleep comfortably. Didn't use much LP either.

I used mine two nights recently.  The power ran out in the morning about the time that we were waking up both times.  Are my batteries a bit bad?  Here are my settings.

2020 Unity Rear Lounge
Thermostat set to 68 or so
Auto for the fan
No other electric on

Possibly. Were they fully charged during the day? In my case I've got 2 x 130Ah Lithionics batteries and 400W solar to recharge during the day. I didn't check the SOC in the morning but these batteries can go down to 10% SOC safely..  Also, the blower didn't need to run much. I only heard it cycle on a couple times.

I have AGM batteries and I think they were fully charged.  The blower ran a lot of the time though.  It was cold out when I used it.

It seems hard to believe that after 1 year the batteries are shot. However with AGM you can ruin them in a hurry if discharged a couple times below 50%. Smart lithium batteries will last you for years and they turn off when low automatically. You get what you pay for in the end. The furnace should of used maybe 25% and no more of the battery. I have a 315ah and will use about 10% with it on overnight. I can also run them down to 10% and they shut off saving the battery.

Yea so the previous owner might have run the batteries down a bunch it sounds like.  They seem to hold a charge at first but I rand the TV and other eclectic stuff the other day and the batteries were worn down really fast.  I am going to time it and see how long they go from full charge 40-50%.

Victron offers a Battery Protect that will shut of flow when batteries reach the cutoff level.

Your batteries are 100% shot then if that's the case. I would definitely get some smart batteries so that they shut down on their own and they are protected if you ever run them low again in the future. You get what you pay for what you pay for. I know my batteries I can run down to 11% without hurting them however I stop at 20 but it's funny but it was a $4000 battery with 315ah.

Frankie,
Have your batteries load tested, that will tell you if they are ruined.
Any place that sells batteries should be able to test, like Auto Zone, OReillys, etc

I installed a Victron shunt with bluetooth to figure out how many Amp/hours I was using when dry camping/boondocking before I looked at replacing the batteries.
I just got new FLA batteries because we never use more then 100amp/hr overnight - cheapest investment you can make if you have an energy plan to stay within what the batteries are rated for.  FLAs can use 50% of rating shown on the battery.
I checked the old FLAs with a hydrometer as there were no longer holding a charge for very long. That showed that a couple of the cells where no longer good.  The water only needs to be check a few times a year so no big deal as they now have the quick release for all 3 cells and access in the UNity takes about 30 seconds.

We camp off season in cold weather as low as 23F(-5C)  we use the propane furnace set to 64F or 18C - we are good for at least 1 week before looking for filling it up again.  The furnace fan does not use a lot of energy so have seen that we only use maybe 40 amp/h overnight.

Yes, furnace uses 12 volts and propane.

Is it worth installing a third Lithium battery for off grid use? ie: heater