Battery life running heater

[TIME2CAMP]

We are getting close to the drive from PA to FL, and planning our overnight stays during the trip. Probably one or two nights stealth camping, and might need to run the heater. Hopefully it will be above 50 at night, we have a small 19 footer. So is it reasonable to expect a single battery to keep the heater on for 6 hours? I plan to test it at home before the trip but wonder what others have experienced.
TIA

[tuffr2]

You probably have a small group 24 12v battery. I stayed in my 22' camper cozy one night in a rest stop but woke up at 4:30am cold because the blower motor sucked all the energy from my small group 24 battery.

So in a 19' trailer your battery will be dead sometime in the early morning unless you have a larger group 27 or 31 with more reserve power. I was smart enough to get a bigger group 27 12v battery on my current trailer.

You should probably take a good sleeping bag or buy a bigger battery and bigger battery box for a larger group battery.

Good luck on your trip

[astrocamper]

Get a bigger battery or just turn off the furnace once you get in you bed with lots of extra blankets or winter sleeping bags.

We have plenty of battery (400 amp-hours) but still turn the furnace down to about 50 degrees once we get in bed. It is quieter at night with the furnace running less. In the morning I make a quick dash to the thermostat to turn up the furnace and get back in bed for 10 minutes for things to warm up.

[jergle]

I haven't tried it personally, but have seen people say to use an electric blanket or mattress pad to keep warm. Uses much less electricity than a heater.

[tuffr2]

To use electric blanket or heating pad you need to be running a generator. Staying at a rest stop/Walmart you only have your 12v system.

All you need is for it to last until 6:00am because it is now getting light outside at 7:00am. Like I said it lasted for me until 4:00am because at 4:30am I was cold. This was in Dec when it does not get light outside until 8:00am. I got in the truck to try to sleep until it was light outside. That sucked but I survived. I was by myself so I did not have a woman with me to stay warmer in the trailer. The truck was my best option.

[Highway 4x4]

A big group 92 battery should do it. I would warm the trailer up before bed, then turn it off. Turn it back on in the morning to warm it up for breakfast. I finally went to 2 Trojan golf cart battery 6 V in series, no more issues.

[jergle]

Originally Posted by tuffr2

To use electric blanket or heating pad you need to be running a generator. Staying at a rest stop/Walmart you only have your 12v system.

Not exactly. You can run AC with an inverter.

[twinboat]

I have overnighted in pretty cool temps with my 26 ft RV using 2 batteries. They are 2 GP31 deep cycle batteries that add up to 200 AH.

I used my battery monitor and checked my heater running and it draws 7 amps. If it ran steady that would equal 7 AHs from my batteries. It doesn't run steady, it cycles on and off.

If the heater ran 45 minutes out of each hour, that would equal 4.75 or round up and make it 5 AH.

8 hours of 5AHs equals 40 AHs. If you have a GP31 deep cycle battery or even a GP 27 deep cycle battery, in good shape, you should be fine.

Since this is a trailer, make sure your charging line is working, otherwise you won't have enough power left for the second night.

[jcussen]

Have stayed in my truck camper with two GC2 batteries. Used a 12 volt mattress pad when sleeping. It only uses about 36 watts when on, and is on a thermostat. Still had 12.4 volts in the morning. No generator needed. Solar next day recharged batteries.

[Mark_K5LXP]

Something I did my first winter with my RV parked next to the house was spend a few nights inside to see how it behaved when it was really cold (for NM). Key takeaway is like twinboat the blower drew about 7A and even with the temps around 30F outside, the furnace only ran about 20 minutes out of every hour to maintain 68F. So actual power needed was only 7Ah/3, 2.3Ah. The other takeaway I learned is that leaving it run all night, ~8 hours set to 68F it took 3 nights to use a quarter tank of propane. Different RV's will have different rates of heat loss so how often the furnace runs is unique, but I know for mine worst case I can easily go a week on battery and almost 2 weeks on propane. Set for a more realistic/conservative temperature and that extends my furnace operation out even further. Point is to do some driveway testing to *know* what your current draw and propane use per hour is, then when you apply the duty cycle of operation at a given ambient and thermostat setting you can predict pretty accurately how much run time you can expect. A battery capacity test goes hand in hand with this so you know what that's capable of as well. I don't see the point in paying all the money for, and hauling tons of equipment around just so I can freeze my a55 like I do in a tent. You bought it, don't be afraid to use it.

Mark B.
Albuquerque, NM

[TIME2CAMP]

90 minutes and still running. I set it at 60, will see how long it goes. I am not sure how good the battery is, am seriously considering a new one. Propane is not an issue, two tanks, one half and one full.
Good idea about the charging line. I am hoping we are in warmer climates by the second night. Then again, was 30s in north FL one year. Had frost on the windshield one morning!

[charliez]

You can do some other things to prolong battery life other that just upgrading/adding batteries. Start with going inside it during the day and making a note of were light is coming in. That will give you a good start to address where heat is being let out. Windows will be the biggest obvious start. You can easily get some Reflectiz online or at a Lowes like store and cut window covers. It's the foil covered bubble wrap. Cut them as tight to the widow frame as you can. That will help them stay in and avoid the need to fasten them so they are easily removed. If there is a skylight in the bath area cover it with Reflectix. You can get vent cushions that are not expensive to tuck up inside the vent's. A layer of Reflectx under a mattress if the mattress is on top of a storage space accessible from the outside is another good use of it. Look close arouind the fridge. They are usually not sealed very well from the outside, especially underneath. I have used foam board and foil tape and sealed the hot side of the fridge from the inside. That was a big air leak for me. A square of Reflectix cut the same size as the vent hood the placed on top of the filter and reinstall the filter will block a good source of cold. Just remember to remove it or fasten it from the outside in an easily removable manner. A tuft of some kind of insulation close up inside the outside shower if you have one is another place to address.


The main idea of this is to keep in what you already heated instead of letting cold in just to reheat the air again.




https://www.amazon.com/Double-Bubble...xpY2s9dHJ1ZQ==


https://www.amazon.com/Camco-Insulat...s%2C173&sr=8-2


https://www.amazon.com/3M-Foil-Tape-...xpY2s9dHJ1ZQ==

[SteveJ.]

Definitely do the driveway test, especially in the absence of a battery monitor.

I didn't see the size/brand of the furnace. Our 20 year old 16k btu Suburban draws less than 4 amps, I believe the 20k btu model is the same. I doubt yours would be a bigger furnace in that size of trailer. Doing the math on these models with a fully charged group 24 battery(again, a guess as battery size was not mentioned that I saw) in good condition will yield a good 10 hours of run time, probably taking the battery down to about 40% with added loads. That would be 10 hours of run time, hopefully the run time would be more around 20-30 minutes per hour.

So it should work but there are a lot of variables and unkowns that are in this scenario.

BTW, they do make 12 volt electric blankets. Ours have a 30 minute timer on them. Turn it on, it shuts down after 30 minutes. Each single size blanket draws about 3.5 amps. Feels mighty good getting into a warm bed.

And yes, Florida(especially northern and even central) can get chilly at night. It's been a while but the record low in Tallahassee is -2F. We've seen the mid twenties a few times. We live between Orlando and Ocala in Lake County.

[TIME2CAMP]

Well the battery has lasted longer than I thought, 6 1/2 hours later and it is still running and the meter shows 75% so we should be good. It is 40 outside, so this was a pretty good test. Thanks for all the feedback, and very happy we don't need to upgrade the battery. I will do a load test on the battery tomorrow to verify how much power is left.