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I'm gonna go on at great length here about cooling vehicles when adventuring and staying cool personally in hot weather in economical ways, 'cause I've done it a lot.
If you don't have the time or attention span for a long article, the TLDR version is:
Air movement is key and you don't always need expensive and permanently installed solutions.
I spent a lot of time, a few years back, hauling expedited cargo 50 weeks a year all over North America in vans, and several years since then wandering the continent in several extended cross-country adventures. In all of these adventures I regularly experienced all sorts of weather and environments in rapid fashion, from urban to rural across North America and in long back country camping treks across different borders.
It was not unusual for me to be up around the north side of the St Lawrence Seaway in Quebec one week and in Laredo TX the next, picking up auto-parts to haul back to the Jeep plant in Michigan. Or back-n-forth over ensuing months, going from McAllen TX to Denver or from North Carolina to Winnipeg MB or Calgary AB. Or heading out from Maine on a gear-gathering trip across the US and back and be gone for sixteen weeks.
What other full-time expediters do is carry a small 5,000 BTU AC and power it with a Honda 2000 gen. Plenty enough to cool the inside of a vehicle for most situations. The small ACs are cheap and the Honda gens are very quiet, efficient, and easily converted to be multi-fuel (propane, natural gas, and petrol - DM for more info if you want). There are other gens, though the Honda gens are time-proven, well-trusted, and long-lasting. Some carried their gen inside, some carried it on their bumper (front or back). I love my Honda gen. It's saved my ass in more ways than one.
Some would permanently install their small AC unit in a rear door in clever, attractive ways. Really not at all redneck or hokey-looking, with little projecting out the back; usually with a snap on weatherproof cover when not in use. Others would keep it portable and block it into a side or front window with an expanding board while parked. Cumbersome to stow when not in use that way, perhaps, but if it kept them out longer when others were saying "no way, José," because of the heat, they were all for it.
I know one guy, not an expediter, who camped a bunch across deep south USA doing research/writing on juke joints and the Blues Trail. He would keep a small AC unit rigged for his ground tent when he had shore power, though I don't recall if he used a gen at all when he did not have shore power. On wicked humid Mississippi Delta nights when no one else wanted to camp, he'd be out there sleeping cool as a cucumber.
> I don't know of any effective air-conditioning units that will run sufficiently on 12v; though that doesn't mean they don't exist.
The user reviews I've read of
the Zero Breeze mostly indicate you have to be in the direct path of the cool air it produces to gain any real cooling effect. I don't know how much power they draw, though I see you have, at least according to your 2019 post, 300ah of battery storage. The Zero Breeze might be finest kind in your small space. Especially if supplemented by through-flow of other air.
There are small RV rooftop cooling units by
Dometic and others, though those I am familiar with need 110 shore power. I have no personal experience with them, though have talked about them with satisfied users. Not sure how much they draw either, or how much they'd keep a small gen running. It's sure something to think about if considering being on the road a lot in hot climates.
For super
dry areas of the country where one might prefer a cooling and humidifying effect, there's a guy in west Texas who has contrived an easy way to build effective 12v swamp coolers using common and easily-ordered materials. Swamp coolers draw air through a medium soaked in water to humidify and cool room air. A conventional commercial swamp cooler would be difficult to use in a vehicle, though they do exist.
John Wells' design, from his
The Field Lab experiments, could easily be used in a vehicle set-up, provided you have the space. As much time as I've spent in the desert borderlands, I've thought seriously of making one for my van. Doesn't help in the PNW for hot
humid days, though may be of use to some in arid territory adventures.
Here's his
Pepino Swamp Cooler, Part 1. His channel has several more vids to the swamp cooler build, as well as a couple other vids showing earlier versions and time-lapse of how he monitors his. He's a very clever fellow. It's been successful enough he has made them to sell to off-grid neighbors.
Over the years, whether urban or back country, the biggest effect-change I've found for staying cool is judicious parking; keeping the front of my vehicle (where all the transparent exposure is) out of direct sun while short-term parking and out of the predominant all day sun if parked longer. Along with a simple roof fan like the
Fan-tastic Vent, (or two; one pulling, one exhausting) it can make a dramatic change in comfort.
Accompanied with the right roof and sidewall insulation and reflective barriers in all windows, I can create a nice through-breeze
without an AC that makes life far more tolerable on the inside of my van than being outside, even with the rear doors open.
Air movement is key. I keep my front windows down a couple inches almost all the time, no matter what the weather, and below my
Weathertech Weather Reflectors, which I've used for ten years to great effect to keep out rain/snow while driving or parked. When parked in hot weather, I keep the rest of the front windows covered with
Reflectix radiant barrier that I've cut to fit. What also works well are the store-bought folding windshield reflectors, usually made of the same stuff that can be custom-bought for windshields, then cut-to-fit for side windows. Put in place simply by friction fit on front windows left down a few inches, they allow my roof vent or other 12v fans to pull air in from the front and across my living space.
I often put a simple thin black cloth over the outside-facing side of the Reflectix on all windows. From the outside to a casual viewer it appears like the dark window of an unoccupied vehicle. Wicked handy for urban stealth-camping or for camping in areas with folks walking about.
Looks like you already have a good MaxxAir roof vent and cover,
@erstwild (and a
very cool SpaceKap Diablo). I'd think seriously about creating a front vent on the forward face or with one of the front windowpanes, if they do not open already.
Also very handy for cooling are simple 12v fans, placed where needed to augment through-air flow. Place them to blow air on you or to pull air from ingress points through living space and out the other end.
I have a few different 12v fans I like, from the simple and easy
Ryobi cordless fans (which use the same 18v batts my cordless travel tools use, though can use 110, too) to the terrific 12v
Fan-tastic Endless Breeze, made by the same folks as so many roof vents, which is portable and terrific in vehicle or RTT.
I also really like the
Sirroco 12v fan; 360º adjustable, 3-speed, ultra-quiet for sleeping, and low power draw. I use it in both van and RTT.
All of these are portable enough to also use outside to create cooling. When in the desert, I'll set one up to blow, or pull, air across my working area, powered by the 12v outlets in van or trailer.
Sometimes that's all I need to make a marked difference in comfort, allowing me to stay out longer and not running for cover or wishing I had a conventional air conditioner.
And sometimes it means I'm the only one left in a campground or dispersed camping area during hot weeks. I consider that a bonus.
You really
can create you own 'air conditioning' without resorting to a powered 110 AC unit.
All that said, the older I get--I'm in my late 60s now after decades of doing this ********--the more I consider the worth of putting a 5,000 BTU unit in the rear door of my van or portable for my front window powered by my Honda gen, and closing myself in when out in the Chihuahuan, Mojave, or Sonoran deserts.
I'm resisting, though, and determined to find a more self-sufficient way to endure the heat.
A good hat can make the difference, too, in the right environments.
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