We make a custom ventilation fan for the van’s pop-out side windows, and we test an hcalory HC-A01 portable diesel heater for the campervan.

Camper van ventilation is critical to keep mold and mildew from ruining your day.

In addition to camping with doors and windows open, enabled by the bug nets, I wanted an active fan to force air out of the vehicle, and some source of dry heated air to give me a fighting chance in the winter.

Ventilation Fan for Pop-Out Van Window

Not wanting to cut a hole in my van, I was forced to work with those pesky pop-out side windows for active fan ventilation.

So I designed a ventilation duct to exhaust air out through the narrow 1 inch window opening, laser cut it from plastic sheet, epoxied it all together and integrated two USB blower fans.

The main structure of the duct was made from ¼ inch acrylic sheet, while the portions that passed through the window opening were made from thin 2mm acrylic sheet to keep the plastic from taking up much of the narrow window opening.

DYI ventilation fan for van pop-out side windows

Send me an email if you are interested in a copy of this CAD model.

A local public library has a maker space equipped with a laser cutter/engraver, making it easy to precisely cut the acrylic sheets from my CAD model.

I used two AC Infinity blower fans because they were the right size, quiet, powered by USB and can be daisy-chained together so that the pair only uses one USB power port.

Ventilation fans basically result in outside air being brought into the van to displace inside air.  Thus, they will cause the inside air temperature and humidity to approach the outside air temperature and humidity.

The value of this comes into play when the inside humidity is higher than outside humidity, such as when:

  • Moisture is brought into the van on wet clothing or equipment.
  • Cooking inside the van.
  • Breathing and perspiration from people and pets inside the van.
  • Using a propane heater inside the van.
Ventilation fan in van pop-out van window

But a ventilation fan cannot bring inside humidity lower than outside ambient humidity.  This is where an externally vented heater or air conditioner comes in to play.

Portable Diesel Heater

Small portable heaters are now readily available in a variety of packages, some burning propane or diesel.  However, these heaters actually produce quite a bit of water vapor as part of their combustion byproducts:

Propane Combustion:    C3H8 + 5O2 → 3CO2 + 4H2O + Heat
Diesel Combustion:        2CnH2n + 3nO2 → 2nCO2 + 2nH20 + Heat

I chose to go with a diesel heater available from hcalory in a portable “toolbox” configuration, and will be running it outside the van, only plumbing the heated air into the van through the front window.

Portable diesel heater for camper van

Here is my thinking:

  • I’m sticking with a portable heater, versus permanently installing it in the van, so that I have the option to leave it behind when not needed, such as during the summer.  My van is small, so keeping all my systems small, modular and portable gives me options to leave things behind when not needed.
  • Running the heater outside the van keeps all of its diesel fuel vapors, combustion exhaust vapors (including water vapor), pump noise and fan noise outside the van.
  • Routing the hot air into the van through the front window, combined with my ventilation fan at the back window, makes sure that the warm dry air generated by the heater circulates throughout the van.
  • With the heater located outside the van, it will be heating outside air to feed into the van.  This is not as efficient as having the heater inside the van, where previously heated air can then be further heated, but my van is small and I anticipate never running the heater on more than its lowest setting, so there is no real loss by locating the heater outside.  I may be singing a different tune if the outside temps drop below 0°F … so we’ll see.  It’s not so much the heat that I want from the heater (I sleep better in the cold).  It’s really the dry air that I want from the heater to manage moisture in the van.
Diesel heating system for camper van

So I purchased the HC-A01 heater, with 5 liter diesel fuel tank.  Similar heaters are also available through Amazon, including other models from hcalory.

The hcalory HC-A01 diesel heater has two operating modes:  an “always on” mode where you select a heat power setting from 1 to 10, and a “thermostat” mode where you select a target temperature.  I have only run my heater in this first “always on” mode.

Operation is very simple.  Simply attach the heater to a 12V power supply and press the power button.  The heater will say “start heating” and go through a fully automatic start-up process, including warming its glow plugs and pumping fuel to the combustion chamber.  This initial start-up process consumes up to 115 Watts of electrical power and can take a few minutes. The first time that it is fired up will take extra long while it pumps fuel all the way from the fuel tank, through the fuel filter, through the pump and to the combustion chamber for the first time.

Once the heater is running, simply rotate the dial on the control panel to select a heating power level ranging from 1 to 10.

Controller for hcalory portable diesel heater

Here are steady state results from a winter trip to a temperate rainforest in Olympic National Park:

  • Heater located outside van, with heated air output run into van through front window.
  • Heater running full-time on lowest heat setting.
  • Exhaust fan running in back window to exhaust air out of van at approximately 40 CFM.
ParameterOutside VanInside VanDifference
Temperature38°F59°F+21°F (warmer)
Relative Humidity84%56%-28% (less humid)

Most import to me, there was no condensation on the windows the next morning!

Also, here are the approximate fuel and electrical consumption rates:

Heater SettingFuel Burn RateTime to Burn Full 5L TankElectrical Power
Minimum (1)0.08 L / hour64 hours12 Watts
Maximum (10)0.34 L / hour14 hours45 Watts

The heater electrical cable comes with small ring terminals.  I purchased an 12V automotive cigarette port adapter cable, cut off the ring terminals, soldered them together with solder sleeves and used a Jackery 300 Power Station to power it all.  This gives me a very long power cable, which I could also run through the front window with the heater outside the van and the Power Station inside the van.

Power cable from portable diesel heater (left), solder sleeves (middle) and automotive cigarette port adapter cable (right)

More on Delica Campervan Conversion

See more posts on my Mitsubishi Delica camper van conversion

Mitsubishi Delica L400 campervan conversion

Delica L400 Campervan Conversion

My reasoning for choosing the Mitsubishi Delica L400 for my campervan conversion.

Interior layout for Mitsubishi Delica L400 campervan conversion

Delica Camper Van Interior

Details the layout and build of the campervan interior, including seating, sleeping platform, general storage, secure storage for photography equipment and swing-arm mounted table.

Mitsubishi Delica L400 campervan with awning camped in forest

Delica Roof Rack & Awning

Detailed description of mounting a Rhino-Rack roof rack and Yakima awning to the roof of a Mitsubishi Delica L400.

Also includes design and build of a quick-deploy “mini-awning” that can be set up in 30 seconds just to cover the side entry door area when the full-size awning is not needed.

Bug screen covering window of Mitsubishi Delica L400 campervan

Magnetic Bug Screens

We make custom bug nets to cover the camper van’s pop-out side windows for both insect and rain protection, with easy magnetic attachment to the van.

Custom rubber floor mat in Delica L400 campervan conversion

Custom Floor Mat

We make a custom rubber floor mat to protect our van’s floor from the Pacific Northwest’s rain, mud and snow.

First Camping Trip

We finally get to test out the camper van conversion on its first camping trip in Olympic National Park to photograph the rainforest and wildlife.

One Comment

  1. Hi Brad,

    I apologize for the cold call, but I wanted to follow-up regarding your diesel heater and to let you know that I really enjoyed your blog posts about your L400 build-out–thanks!

    Diesel Heater – How happy are you with it? Is it sufficiently water resistant for PNW? I don’t have an awning yet and I’m not sure if I’m going to get one based on my intended usage, but I can imagine that wind-blown rain might be a problem for the heater unit and I was wondering if you had any thoughts as an owner/user.

    Jeff Sturm

    • Hi Jeff,

      Yes, I am happy with the hcolory diesel heater “tool box” so far. I press the Power button, and it goes through it’s little start up routine and starts making heat. I turn the dial to change amount of heat, though I usually just leave it on lowest setting since it really isn’t that cold around here in winter … just really wet. I press the Power button again, and it goes through it’s shutdown routine. So I really can’t complain about functionality. The manual kinda sucks, as is often the case for Chinese-made devices like this: no assembly instructions, poor English wording and grammar. But you can download the manual from their website and follow my assembly process on Youtube.

      I currently deploy the heater on a 2-step ladder and under an awning, so that rain mostly keeps off of it and it’s not being hit by raindrops splashing up off the ground … and I keep the hot combustion exhaust tube away from combustible materials that may be on the ground.

      As for water resistance, I would not want to leave it out fully exposed to rain. I’ve often thought that it would be convenient to deploy the heater without having to deploy the awning, as it is often not worth setting up the awning if just making a quick sleepover stop for the night. I’m not too concerned about wind-blown rain coming in under the awning, and I wouldn’t want the awning out in heavy wind. I was thinking to make some kind of waterproof blanket that could be draped over the heater, but the combustion exhaust tube gets very hot and care would be needed to avoid melting/fire. Maybe there is a way to clamp an umbrella over it? But I wouldn’t want strong wind to blow an umbrella or blanket in contact with the combustion exhaust tube. Maybe sewing a tight fitting waterproof cover that Velcro-ed on and had proper inlet/outlet ports could work!

      One tip: keep the steel combustion exhaust tube slanted at least slightly downhill. This allows any water drops caused by combustion to dribble out. This water could accumulate inside the device if the combustion exhaust tube was sloped uphill.

      Best regards,
      Brad Mitchell

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