In a previous article, I discussed the feasibility of running a small, room-type air conditioner using a portable solar setup, so continuing the whole ‘climate-control' theme, I thought I should address the issue of what is the best portable heater for your solar powered camper or cabin. After all, I want to make boon-docking a comfortable, year round activity.
All electric generated heat from a radiant or convection heater (space heater) is produced by way of resistance in a circuit and a process known as thermal conduction. No big deal…. pass enough electrons through a circuit and heat is the by-product. Add an electrical resistor (heating element), and you raise the heat produced exponentially.
This is easily illustrated by the resistance created by the incandescent light bulb. The bulb creates resistance in the circuit and thus creates a substantial amount of heat as a by-product of the work (illumination) it performs.
600 pound gorilla time
Electric radiant heat for our portable solar system and camper or cabin is essentially a bad idea. This heater type simply consumes too much battery power to be a viable option. Lets look at a couple of statistics:
A 1500 watt space heater at 110 VAC is using 13.6 amps per hour of electricity. Over a 10 hour evening/sleeping period in your rig, this adds up to 136 amps, if it runs at full tilt.
For the sake of practicality, let's assume it runs half the time and switches to low power or off half the time after warming the space, so it consumes 100 amps of AC current per night.
Because of inefficiencies in all power systems, we still need 125 amps of power during the day to replace the load drawn from our battery bank, the power used in the conversion from DC to AC, etc. This is possible, but only if we have lots of PV modules and several batteries to share the load. See my article where I go into power production detail here.
Sure, if you carry 1000 watts of solar panels, on full sun days and accounting for inefficiencies in the circuit, you would produce something like 800 watts divided by 12 volts = 66.66 amp hours of power. So as long as you had good sun for 2 hours and had adequate batteries, you could replace the heater-drawn power.
Here is a handy solar insolation (Peak sun) map that might help you estimate your available solar input: Wholesale Solar Solar Insolation Map
However, traveling with 1000 watts of solar panels may not be feasible, unless your rig is a large motor home or similarly spacious trailer. Consider the logistics of what this entails, using the Renogy 100 Watt, 12 Volt Monocrystalline Solar Panel – New Edition, as the standard:
Each 100 watt panel is roughly 4 feet by 2 feet and about 18 pounds. So imagine mounting ten on your rig! 80 square feet and 180 pounds of PV modules is no small logistical exercise.
Now consider that you are doing this to replace just the power used by a single, small electric space heater! You have yet to consider the power used by your electronics, pumps, lights, etc, which all contribute their share to the consumption side of the equation.
Amazon.com does sell very small electric space heaters in the 350 watt range, which is pretty neat actually. 350 Watts at 100VAC = 3.18 Ah of power consumption. If your camper is small, grabbing a couple of these and plugging them in at opposite ends of the space might be an option. It may certainly be a backup option to any primary system you choose to adopt.
Heck, this Lasko Personal Heater uses only 200 Watts! I always gravitate towards Lasko products and have their fans all over my home – some are more than 15 years old and still going strong. At about $20, you would probably want to pick up several of these, but their 1.8 Ah draw (each) is rather attractive.
You might be thinking at this point that this is all interesting (maybe not!) and possibly workable for your ‘frgid' 50 degree Florida winters, but up here in God's country, I need lots and lots of heat, or somebody is going to freeze to death.
If this sounds like your situation, you're going to want a primary heat source other than electric for your camper. Read on.
Let It Burn!
Serious heat is going to require burning a significant amount fuel, or a significantly efficient heater burning a reasonable amount of fuel. Either way, you've got to provide that fuel, and that likely means you're packing the propane.
You may decide that a kerosene heater is best for you, and the current models are effective and safe, even for indoor use. However, I am interested more in dual-purpose products and propane is more adapted to other things beside heating, such as cooking and water-heating. Kerosene heat may be the best and possibly only choice for extreme cold camping, but that just isn't my cup of tea, as it were, so I'm going to focus on propane here.
Now, I have seen and experienced wood heaters, and various vented stoves whether wood or propane, and in my opinion, unless you must have a dual-purpose stove and cooker, these are not the best idea for a camper. More practical for a cabin perhaps, but even then, logistical problems are created. I will touch on just the more obvious ones:
- inefficient – much of the heat you create is vented outside
- soot and ash you are producing can be significant over time
- most stoves require you crack a window or let air in to support the combustion process
- stoves cause condensation buildup as cold air is drawn inside
- stove-heat is more difficult to regulate
- wood stoves require a continuous supply of properly sized, dry fuel.
Quick story again (groan)…. my neighbor has a beautiful, vintage, pot-belly stove he got from an old train depot. It is a true work of art in cast iron, with shiny (nickel?) inlay and other features that just make you stare at it, even in summer when its just sitting doing nothing.
The stove is over sized for his 2000 square foot, 2 story house, and the funniest thing is that on the coldest days of the year, his front door – which is 5 feet from the stove, is always wide open. The stairs to the second floor are on the same side of the room as the stove, so the air current from the door moves the heat upstairs and you basically slow-roast up there.
So, keeping the house comfortably warm for him is a challenge to say the least. Depending on where you stand or sit, you are either very cold or way too hot. There is a ‘sweet spot' of course, which is the perimeter around the stove itself, but most of the house is outside that space.
Portable Propane Heat to the Rescue
The reviews are in, and their are a ton of them, mostly praising the efficiency and convenience of the Mr. Heater portable propane heater. I say why not go with the herd on this one and invest in a proven, field-tested heater?
On the lowest setting, this 20 pound heater will use up both its 1-pound on board propane tanks over an 8-hour period, so you'll want to pack a supply of the tanks.
For extended cold weather boon docking, consider the optional hoses to connect the Mr Heater to your camper's propane tanks for extended operating time.
If your space is about 400 square feet or less and you need to be toasty-warm without killing your batteries and otherwise hogging all available power from your other appliances, I would advise giving Mr. Heater a close look.
I threw a curve of sorts with this article because it turns out that the best heater for a solar powered setup may in fact be a propane heater and not an electric heater at all.
Of course, you might also benefit from a combination of a portable propane heater in your main cabin, and one or two tiny Lasko personal electric heaters, perhaps in a small bathroom at the other end of the coach or cabin.
There is no reason to freeze half to death, or really, to be uncomfortably cold while boon docking. There are so many great choices today for low-powered heat sources, you just have to decide what is best for your latitude and budget.
If you have a huge rig and a sufficiently capable solar setup, your choices are endless, from heat pumps, to convection heat to the more thrifty propane and kerosene. I'm jealous! But that's OK, we all have excellent choices…..there has never been a better time to experience off-grid living. It is accessible to everyone, just do your homework.
Stay warm out there!