Can I Run my RV Furnace on Batteries?

RVing across the country has always been a dream of mine. I believe it is the freedom of it that attracts me. Being able to wake up each morning, pick a direction, and start driving. There are no deadlines, no commitments, just you and the open road. If you get too tired or want to take a break then no problem. Just find a camp site or rest stop and pull right in. In most cases these camp sites have thirty or fifty amp outlets for RVs to plug into as well. This shore power connection gives you all of the creature comforts from home including air conditioners, furnaces, microwaves, coffee makers, and so much more.

But, what happens when you go to make camp and find that there is no shore power available. There is no outlet for you to connect to. While some people run into these scenarios accidentally there are others who seek these situations out. It is known as ‘dry-docking’ or ‘boondocking.’ Basically, it is camping with your RV/motor home without a source of shore power. In these situations there are a few ways for you to get power.

The first and most reliable way is by using a generator. Most motor homes and RVs today have built-in generators that come with the unit. These built-in generators can actually share the fuel source that your RV’s engine uses. It makes for a relatively easy setup. If you don’t have a built-in you can also use a standard portable generator. Whichever option you use here you will have power provided to your RV and it’ll be just like you were at an official camp-site with a power source.

There is another way to get power to your RV though and this is what the article is about, batteries. Most RVs come with two deep cycle batteries that are charged while the engine is on. These batteries are also charged when your RV is connected to shore-power or through a generator running. When the engine is off and you are NOT connected to a generator/plug-in then your batteries can still provide you with some basic power.

The first thing you should know is that batteries are substantially weaker versus a generator or shore power connection. A generator/shore power will give you full power without any trouble. Batteries however will run out of juice. This especially holds true if you have a whole host of appliances and electronics connected to the RV. I wrote a topic the other day about how long RV batteries can last when dry-docking. You can read the article by clicking here, but the short summary is that it can range between two to three days.

Powering a Furnace with Batteries

So the question asked in this article is can your RV’s furnace be run with just the batteries? The furnace is quite a bit different then the air conditioner. Air conditioners are notorious power hogs and frankly just cannot be run on battery power alone. If you tried you may only end up with cool air for a few hours before the batteries are drained. The good news is that RV furnaces are less complex, have less moving parts, and overall use much less power.

Chances are your RV’s furnace is propane based. So, what this means is that the actual heat being produced comes from the propane and not the battery itself. This is similar to how a water heater can still work during a power loss event. The only battery power needed for the furnace is the blower. The blower is just what it sounds like. These are the fans that move the produced heat around the cabin.

When it comes to heating your RV by just using the batteries the typical rule of thumb is that you can get through the night with one battery. If you have two batteries then you can get through a couple of nights. That being said, there are a variety of variables that can throw this off. For example, where is it that you are camping at? Are you in Maine in January? Well then your heater is going to be running constantly and so is the blower. But, if you are in South Carolina in March and need a bit of heat to raise the cabin temperature up to the sixties then your heater/blower will run for a bit, and then turn-off. When the temperature drops the heater will turn back on. This is KEY.

If your heater and blower are running all night without stopping then your battery is going to drain much quicker. But, if your heater is turning on and off again throughout the night as needed then you will end up saving battery power. The other thing to consider here is just how many other appliances and or electronics do you have that are draining power from your RV’s batteries? Do you have a lot of lights on? The radio? Television? Other appliances? Each one of these will drain battery power.

Remember folks that it is very important to keep an eye on your battery’s charge. Watch the percentage. If you start to dip below forty percent then it is time for a recharge. This is why I really have to emphasize to you that a generator, even a small one, are essential when it comes to dry-docking. Even if you do not plan to use the generator it gives you peace of mind. You know that if your batteries do go to low and you need a charge then it is as simple as hooking the generator up and flipping her on. Your batteries will then be charged back up and you can start heating again.


So folks in conclusion, yes your RV’s furnace can run on your batteries. You just need to make sure to keep an eye on your battery’s charge percentage and also have a back-up plan to charge the batteries in case you do go lower then you should. I’ve seen some examples where folks purchase a small two-thousand, or even one-thousand, watt generator. Most RV’s come with a four-thousand watt generator… but these smaller ones will produce enough power to help charge your batteries during these overnights. In some cases folks have installed solar panel systems to give their RV batteries that extra charge they need during the overnight sessions.  Here at ToughAssTools we recommend this twenty-two hundred watt inverter generator from Generac.. It is small, easily portable, and will give you the power you need to charge up.

If you are interested into trying your first ‘boondocking’ trip then please please have a back-up plan such as the generator examples we mentioned above. A trip can go south fast if you find your batteries drained with no way to charge them back up.

I hope this article was helpful to you and stay warm while camping!

Thanks for reading,

Alec Johnson




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