Community Forums

Mogulite · 08-11-2019, 04:37 PM

We were dry camping last fall and it was cold enough that we left the heater on while we slept. We set it at 65 and the house batteries were dead when we awoke.

Should we avoid using the heater with the Inverter or is a half an hour here and there okay?

Thanks

Unplanned Tourist · 08-11-2019, 04:45 PM

How about getting something like a "Buddy Heater"? Just use it while you are up, and get some more blankets for while you sleep.

Happy Glamping.

jcussen · 08-11-2019, 04:52 PM

Agree with Unplanned, a buddy heater is fine when awake. Otherwise use your propane furnace. Even small electric heaters use 1000 to 1500 watts, very hard on your batteries.

bamaboy473 · 08-11-2019, 04:52 PM

Somebody else can do the math, but a 1500W heater will suck batteries very, very quickly. Does your coach have a volt meter that tells you house battery voltage?

If so, run the heater for an hour and measure the Begin/End voltage....then get more blankets.

docj · 08-11-2019, 04:53 PM

Your batteries can each store roughly 200 Amp-hours of energy and are best preserved if you don't draw them down more than roughly half way.

A 1500 watt heater operating from 120V power will draw 12.5 amps. If your inverter was 100% efficient (which it's not) 1500 watts would draw 125 amps at 12 V. So regardless of the exact size of your heater, it will typically draw more than 100 amps from your batteries.

Therefore, it wouldn't take all that long for you to completely discharge the batteries. IMHO high current devices such as heaters shouldn't be operated off of inverters except for very short periods of time.

MSHappyCampers · 08-11-2019, 04:56 PM

Quote:

Originally Posted by docj

Your batteries can each store roughly 200 Amp-hours of energy and are best preserved if you don't draw them down more than roughly half way.

A 1800 watt heater operating from 120V power will draw 15 amps. If your inverter was 100% efficient (which it's not) 1800 watts would draw 150 amps at 12 V. So regardless of the exact size of your heater, it will draw more than 100 amps from your batteries.

Therefore, it wouldn't take all that long for you to completely discharge the batteries. IMHO high current devices such as heaters shouldn't be operated off of inverters except for very short periods of time.

X2! Good advice!

TOM GUY · 08-11-2019, 04:59 PM

An electric blanket could be a good choice, since the power needed is low; the problem is that some electric blankets and heating pads cannot tolerate MSM inverters.

If you have a PSW inverter or an electric blanker rated for inverters, you could be fine.

Also, a short usage of the space heater on low power should be fine; just be sure to to monitor your battery condition.

Tom

theoldwizard · 08-11-2019, 05:02 PM

Quote:

Originally Posted by TOM GUY

An electric blanket could be a good choice, since the power needed is low;

Better than a electric blanket; electric heated mattress pad. And carry and extra blanket, or two, after Labor Day.

Sweetbriar · 08-11-2019, 05:22 PM

Resistive heater (aka electric) will quickly deplete a battery bank. Simplified math, 1800 kWh from 12VDC is 150 amps an hour not including all the losses along the way. With a 50/50 duty cycle (on/off time for temp setting) you might have been able to get 90 minutes or so out of a two 6VDC GC2 batteries before the inverter shuts down for low volts.

I've found an electric blanket along with a low temp setting of the propane furnace when we've camped off grid works well. The blanket wattage is fairly low along with the maybe a 30/70 duty cycle. The furnace blower is an energy hog but not nearly as much as a resistive heater.

hohenwald48 · 08-11-2019, 09:40 PM

Why not just run the propane furnace?

Dutch Star Don · 08-11-2019, 10:52 PM

Same question.....what's wrong with your propane heater. It will still run down the batteries, but not as fast as an electric heater on an inverter. Turn the propane heater down to 55-58 and cover up.

When we boondock at Yosemite, during Thanksgiving, we let a Buddy Heater run all day to keep the interior components warm. I never liked using it at night, but decided that it has enough protection, not to kill you. I open a window in the bedroom and run the Buddy Heat in the main cabin. This lets the heat migrate back and the window provides fresh air. I also leave a roof vent ajar to keep the condensation off the windshield/windows.

twinboat · 08-12-2019, 12:30 AM

Delete

twogypsies · 08-12-2019, 12:40 AM

During our 16 years of full-timing we used a propane catalytic heater.... nice even warm heat. We didn't use any heat at night.... warm comforters.

A RV furnace just wastes heat and uses electric.

Kodiakan · 08-12-2019, 01:43 AM

I'm not so sure that the heater he is talking about isn't a propane furnace as I don't see "electric" anywhere in his post. If indeed he's talking propane than yes, a half hour here and there will work. Left on to 65 it would depend on how cold it was outside but yes, a propane will run batts down. The lower you set it, the longer your batts will last (obviously).