Camper van ventilation without using window vents or cutting holes (first see comment by @drewcress)

[@drewcress]

I appreciated the effort here but a hidden issue with this approach is most vehicles actually switch to recirculating air as the car turns off. The fresh air inlet is closed to help prevent dust, moisture, and rodent ingress. I spent a fair bit of time figuring out to get both the servo and fan to behave but it gets much more complex as a tap can change the starting position of the servo and break things when the car turns back on. I've tried other ways like a second battery just for car aux power (works) but ultimately the power consumption is just to high to make it worth the effort. What work a bit better is to take a small blower fan and point it out the cabin pressure flap (where the smoke exits). It's non destructive and the difference in pressure will pull fresh air in. However, it's a very small exchange when the van is otherwise closed up.

[@SemiSeriousLabs]

Thank you for sharing! Just to be 100% sure of my own setup, I just now did a smoke test. I put the machine under the hood and confirmed smoke came in through the vents with my battery-operated setup running. So I'm ok, at least, but I wish we had an easy way to tell which vehicles close their air inlets as they turn off. Out of curiosity, did your tests also use a three-wire blower fan? If not, and you had a two-wire type, can you tell us what voltage range worked best and how you controlled the voltage?

[@drewcress]

​@@SemiSeriousLabs Interesting! Glad to hear your setup is working as expected. I was a bit disappointed to find the Gen2 Toyota Sienna was more limiting. An aside, but I'm just now noticing much more vertical your air inlet is on the Gen3. Perhaps Toyota came up with a better overall design there given the trouble the Gen2 had with the climate control servos. Maybe Toyota opeted for a bit of an air mixer setting by default too? I could see some upsides to that alongside a more vertical inlet. As for more exact numbers, I'm afraid I'm not much use there. I was looking if it might work on multiple vehicles at the time and just doing some preliminary testing. It was mostly with a small 12v battery and a pwm controller with a dail, precise it was not. The vehicles in question didn't have a climate control system and their default adjustments where just some resistive elements (hints the silly high power consumption via the aux power approach). All of the vehicle (Express, Promaster, Sienna) did have a recirculation servo that defaulted to internal air when off though. After my testing and a bit more reading, I believed that was generally going to be the case / challenge on nearly all vehicles since the early 90s and onward. Nice to know that isn't so with some newer models with more well adjusted climate controls system. I'll need to do some more reading to understand exactly when and how they differ. Thank you for your video and your testing!

[@ericcamolinos3740]

I think the recirc flap closing with the car off is only common on older vacuum controlled systems, as there's no vac to hold it open when the engine is off.

[@drewcress]

​@@ericcamolinos3740 It seems nearly all 90s+ and newer servo based systems do this a deliberate feature as well. I'm having trouble finding a modern passenger car that doesn't do this but the lack of a feature isn't the easiest thing to hunt down. I'm still looking, but I've found some hybrid cars use an AC system that can air mix though it still unclear exactly how these behave when the vehicle is off. I did find a couple of RV systems that allow the fresh air intake to be open when the vehicle is off, but those appear to have been dropped in favor of the lower power rooftop options. So far, I think most adaptations of the above approach would need to disconnect the recirc servo from the climate control / computer and just run it manually via a separate battery and switch for best result. I do want the approach to work simply for elegance of the solution, but at that point, there are cheaper and easier options available as well.

[@SemiSeriousLabs]

@drewcress @ericcamolinos3740 I'd feel bad if someone went down this path on a car with a closed recirculation flap. So, I edited the title to help them see this discussion. Thanks again you two!

[@datguy2730]

Finally! Someone who is talking about CO2 levels in a van! I have posted the CO2 measurement question to numerous van KZbinrs and not one really acknowledges the issue. Thanks for taking the time to do this posting!

[@montanadan2524]

As an electronics engineer, I found the approach interesting but it reinforced my approach of just cracking the window.

[@ontheroadwithtenzin]

I have a converted Dodge Grand Caravan. My approach is simple. I have good rainguards on the four main windows. I crack to kittycorner windows based on the direction the breeze is coming from. I lower the windows to just above the bottom edge of the rainguard. I have window insulation that will fold down the and allow air to pass thru. If I need more air I clip a good USB C rechargeable fan to the front row seatbelt and one to the opposite cross corner area. I don't remember where I heard this but you need 6sq inches of open window for ventilation when staying in a mini van. Doing this I do not get cold, there is no moisture buildup on the inside, rain does not get in and no one can see the windows are cracked open. Been doing it for years with no issue. And I have bug screens. Easy peasy.

[@MYYTVI]

Finally someone did it! Have been thinking of the same solution! Thanks brother! 🤘

[@markmcla]

Very clever! I never thought of that solution to air circulation. Thanks for sharing! -On my 2007 toyota sienna minivan, I cut a hole near the rear of the vehicle on the driver's side. And then I cut a hole in the roof for one of those 6" mushroom vent fans. These holes provide a path for air circulation and it works well. And I can cover all of the windows. -But, like you pointed out, I had to make permanent modifications. I'm not worried about permanent modifications because my minivan is 17 yrs old. And if I ever sell it, then I'll just sell it as a minivan camper. I posted a video on my minivan camper on my channel.

[@SemiSeriousLabs]

Nice. I'm jealous of your heater. Cool how it has a heat exchanger instead of burning the same air you are breathing, like my Buddy Heater does unfortunately.

[@loughkb]

Hey that's pretty smart. And I'll bet you on the lowest setting, it's moving enough air to keep you ventilated. It doesn't take much air movement. Now you need to find the female connector and make a y assembly, then you can build it all into a nice little box that you stick somewhere out of the way but accessible.

[@DustyyNomad]

Brilliant idea! Ive wondered if this would be possible and have never seen anyone pull it off until now. Great video!

[@andylewis4695]

Much better than cutting a hole. If you used an arduino for the PWM signal than you could also have the fan on a timer for something like 2 min on, 10 off. Also, if you put in a few diodes on the oem side and the homebrew side, than you should be able to leave it all connected all of the time.

[@Chris-ut6eq]

Good info, good testing and like any design solution there are always trade-offs. Something to consider, the max air fan type is made to move air with little to no differential pressure while the car fan must overcome differential pressure to force some air into interior(through a tiny hole) which forces the air out the rear vent. For building IAQ, it is suggested that one person needs 10-20cfm to avoid stale air.

[@mattmccallum2879]

This was amazing! I’ve only seen one other person do something like this…tempting for not having to drill a big hole in the roof for sure!

[@lightdark00]

Wow, adding to the great ideas for stealth. The only addition would be for less battery usage is for it to cycle on and off, allowing the CO2 to get in the 800-1000 range to not cool things excessively in the winter.

[@aussie.prepper]

Power consumption of the OEM fan is much higher than any after market ventilation fan.

[@stephenlabarre7890]

I haven't even finished watching the video and I'm impressed with your logic/knowledge. Thanks. It gets me thinking about things I might explore.

[@dennislaw2135]

Way too complicated. But you’re very fortunate to have such an extensive knowledge of electronics to pull this off. My brain cells only allow for window vents. Otherwise a good video.

[@sprinterfix]

Keep it up! I am going to copy this idea for my van which already has a 12v system. Looking forward to seeing more videos

[@WeirdOneOz]

Great idea thanks for going to the effort of testing it all.

[@hejasverigeee]

Been looking for exactly this solution! Greetings from Stockholm Sweden Europe 🇸🇪♥️

[@z6006]

Nice work man. I'm going to see what else you're up to in your other videos

[@nestogonzo1]

Nicely done, I like the car camping idea so I went hybrid...

[@EngineerK]

Was waiting for the CO2 retest with the fan running... You could redesign your system with an esp32 microcontroller running Esphome plus a CO2 sensor and relay. Can probably do the pwm on the microcontroller. That's if you really want to geek out 😂

[@max7w311]

May I have some advice on how to do this. I have an arduino microcontroller but heard better things about esp.

[@EngineerK]

​@@max7w311 lots of info on the Esphome website. It's very easy to integrate esphome devices into home assistant. You can do a good chunk of the automation work on the device but generally speaking this is easier to do in HA (in other words, just use the Esp to collect the data, automate against the data in HA but that being said you can run an Esp device with automation autonomously).

[@wjcferguson]

@@max7w311 ESP-32 chips are dirt cheap and can be programmed with the Arduino SDK if you want familiarity. They include Wifi and Bluetooth and a /lot/ more horsepower than an Arduino, but e.g. the S2 mini boards are

[@markeh1971]

Hi, it’s a good idea to use the existing OE,fans, ducting and filtration all provided FOC. Most motors are PWM driven now so it’s just packaging and powering the unit. I have seen a video where for stealth he put PC fans in the rear door posts and sucked the air out that way, venting down the post to the ground, using existing air path. You need air flow but might not want bloody big vent on top of your roof showing it’s a camper! Good video, take care M.

[@rhiantaylor3446]

I always thought this was the best approach but for different reasons - just want to keep the roof completely clear for solar cells. Next challenge is to get the A/C running without the engine..... By the way, don't you need to interpose a diode (a beefy schottky diode) in the main 12v feed to the fan so you can power it without removing the wiring loom plug or back-feeding into the rest of the ignition circuit.

[@SemiSeriousLabs]

Interesting idea!

[@OdysseyCamper]

Clever! I cut dual holes in the floor with 275 CFM bilge fans w/speed control. In hot weather, one serves as a vent for the AC unit. In the extreme cold, it is the intake for a diesel heater. But yours might be the most clever I’ve seen. Subbed

[@InspiredByBrad]

When I was camping in a 2004 Prius, I found a silent and very efficient way to ventilate the car: I located the one-way valve air outlet flap vent hidden at the back from inside the hatch (had to remove some interior panels to reach it). I used some 5 inch ducting at home depot to attach a 120mm (approx 5 inch) 12v Noctua computer fan and a squaure flange with some weatherstripping, tape, screws, zip ties, etc., and a simple wire with inline on-off switch. I left the dashboard vent positioned to allow fresh air to be sucked in. This moved enough air to remove humidity, window fogging + breathe fresh air/oxygen while sleeping etc, but wasn't enough airflow for significant cooling. It was great in the cooler weather when some fresh air was needed without losing too much heat. It helped greatly for quiet sleeping since I could close all the windows and still breathe fresh air.

[@SemiSeriousLabs]

Yes, this sounds ideal. Thank you for sharing.

[@lisapayne185]

Great information thank you and you’re helpful helper so very very much!

[@YoureNowOnTV]

Interesting video. Thanks for going to the trouble of making and sharing it. I wonder if splicing in another hose to the intake vent with a small fan would also work ? That way if you wanted to sell the vehicle no-one will ever know the original hose was cut (If you replace or patch it)

[@cvcoco]

I get the idea and its very interesting but I think its easier to keep a window cracked and have a way to secure the window.

[@jansweeney1333]

👋 very interesting using a power drill battery ( ryobi). Too technical for my brain to wrap around though. Well done ,with more simplicity & commercial use you could make a patent & be rich selling it.! 🏴󠁧󠁢󠁳󠁣󠁴󠁿👏

[@terrentech]

PWM is pulse width modulation. I didn't know this was used in automotive / blowers. Wow, like computer fans. Wild

[@tybrady4598]

Man, thanks for the CO2 info. I wrongfully assumed my van would naturally circulate a tiny bit of air through the vents. Your meter shows otherwise. Plus another comment on here made a good point that many vans close the vent flap to prevent bugs dirt and rodents from getting in when the vehicle is off. I have been cracking my windows, but I see I might need more than that. I’m gonna buy CO2 monitor.

[@Connor37911]

Agree, though I don’t think most vehicles are air-tight enough to make people pass out. I am no expert, but seems like there would be many cases of it from people sleeping in cars, or that it would be a risk when driving. But higher CO2 will definitely cause some symptoms, like feeling tired or groggy, headaches in some, etc.

[@BoopSnoot]

If you are talking about the exit flap, its a simple one way valve. Something from outside pushing in can't get in, it can only be pushed out to release air and it does so passively. If you mean on the intake, seems odd it would need to considering that there is a cabin air filter in the way before the air gets inside the vehicle one way or another and it traps debris.

[@testi2025]

Most car HVAC systems have a simple 12v input for auxiliary fuel heater like Webasto. So in most cases you need a simple switch. Just look up electrical drawings of your car and you should find it. These auxiliary heaters are popular in Scandinavia.

[@wilsonwombat3456]

I have a pop up sink waste in the step well; a muller vent on the roof and underneath a noctua 12f fan(0.07a) with a variable switch. Max air exhaust about 7 litres per minute.

[@neilmckay8649]

Ventilation effectiveness comes to mind, getting the air to where it's most needed. Floor vents as part of a multi vent system seems to have merit.

[@Rick-qf5de]

In modern vehicles when the vehicle is turned off the fresh air vent closes.... And a modern vehicles chips , will know there's something being tampered with...

[@crissgen]

Thanks , was very interesting, even if I didn’t understand, i bought a liteAce van , I will just open the engine access by the passenger seat 😂

[@someonelse5847]

Once the rear outlets was found, I would have put a fan there to evacuate air, and either let it suck trough the car system, or a window crack. I also saw someone make a gap in the doorseal to ventilate a car

[@SuperADI2]

Thank you for the video, very useful information s 👍👍👍

[@AWBabbage]

Any vehicle blower fan that uses a resistor block for speed control instead of a pulse width modulation system is going to be very inefficient. There are lots of rechargeable and USB powered clip on fans available that are cheap and easy to use. My minivan has rear air vents for rear passengers. Once I install a large ‘house’ battery I am going to look into adding a relay or manual switch under the dash to allow running the entire accessory fuse block off the house battery when the engine is off. This would allow me to use all the fans, lights, and power outlets that are built into the van from the factory without draining the starter battery. I would replace the interior light bulbs with LEDs.

[@konserv]

For PWM you can also use cheap $1 servo tester. It should also work. This type of control signal is everywhere - from servos in RC hobby and computer fans to cars and literally almost every variable speed fan in any equipment.

[@konserv]

And hooking up something like "webasto thermo top evo 5 petrol" for gasoline cars or any other diesel parking heater for diesel car/van is reasonably stealthy, compact and integrated.

[@SemiSeriousLabs]

I would LOVE a Webasto heater. Someday... for now I'm going to get a winter sleeping bag.

[@sgw3612]

Regarding smoke exhaust. On my van there is a built-in storage bin in the very back behind the driver. Under it is an access panel with some of the tire change equipment. Inside that access panel there's also an exterior vent.

[@crackerjack6075]

I saw this vid a month ago and decided to improve my internal air because I am One-in-a-Van, but I found air quality even worse that yours !! I frequently sleep in this van, so the measured co2 was not healthy at all !! ***I think you'd do this better than me, but here I kinda blundered forward, but I installed custom. My Bluetti power station is adequate to easily power & Batt. the installed fan. in-flow air; under car, just behind the front passenger seat, I cut a ~4" hole to accommodate a custom airbox from a plastic water jug (for prototype I just went cheap materials ~$11),. Then I housed therein an off-the-shelf auto cold air K&N filter ($13), mated to 4" clothes dryer flex hose pipe (~$5, but I already had it), connected to an AC (and DC option) weather proof inline duct fan with variable speed control ($30 AC Infinity). I finished inside output by continuing with clothes dryer flex hose and a plastic directional out-vent mouth, where I also protect against any blow-by pollutants with another washable cloth filter (but so far it stays clean). The fan is also direction reversible and I direct out-flow anywhere in the van. This is a garage make-shift prototype and I keep breaking it. But I like it's utility & results enough that I intend to now graduate to more completed components finish. Then maybe I'll reverse the design (without the filter) to create an exhaust scheme back of the van.

[@acs4llc]

The rear vent/flap is there so the doors close easy vs an airtight cab.

[@WalterPidgeonsForge]

I used a bilge blower for boats… and installed it next to the spare tire Since it was easy to attach flexible ducting and used a round, screened soffit vent with a screen from HD.

[@SemiSeriousLabs]

Cool! I had to look up what a bilge blower was, and they do look useful for a variety of setups.

[@Ratsnacker]

Great idea. Thanks for sharing!

[@MYYTVI]

You could have done an air quality test with a fan on to determine the lowest setting for the fan to maintain air quality. 😉

[@marcbruneel1858]

If it works is not tested af thé end with his son, pitty

[@BobHill-s2c]

Good video, no blubber. However, if you're living in a van, charging the 40V somewhere everyday is pesky.

[@awesomearizona-dino]

Good work, ive run into similar issue with modern radiator fans, i may try your experiment.

[@YellowstoneBrew]

I have always wanted to do that. Thanks! But yes, those car fans are power suckers. I wonder if the outside air door is left in the open position when ignition is off? If so, perhaps fashion a cowling around a 5v computer fan, position it over a vent, and plug it into a usb port. It'll only draw maybe 150mA.

[@neilmckay8649]

His and your ideas are neat but one potential issue is any blackout curtain fitted between the front and sleeping areas ... fresh air will have a restriction to overcome.

[@arselihp]

Cool video. Intrigued by "cabin pressure flap" mentioned in the comments (i.e., the smoke hole)--do all modern cars have these?

[@clevelandexplorer2221]

Hi pal, I love this! May I ask, with the accessibility to the wires, why not wire a switch before the house battery, so when parked it'll switch to house np. Then back when driving. Very sorry if I didn't hear something about that. Interesting use for the batteries, and I'm not even sure I thought of the dash system. I guess I figured it'd all be dirty, used full time, being around the engine bay I presume. But a hepa filter should be standard and therefore should do for this use :o though filters do need cleaning more regularly this way

[@gdlerner]

I don t have this problems I drive a defender 110 many holes everywhere😁

[@thelegion_within]

that's a really neat hack!

[@thewunderhase]

thats an insane good idea

[@firstnamelastname2669]

This makes me wonder why manufacturers don't make this a feature for dog owners. Leaving a window open isn't why secure.

[@ThisisForTheTV]

2010 2015 Prius solar would run the HVAC blower off the solar panel to keep temperatures within reason. Not really for pets but idea and technology is there, they just don't. It also had a button on the remote to turn on the air conditioner remotely.

[@sgw3612]

🤔 would just hanging a 5-volt fan in front of one of the dash vents work? Would that fan be drawing from the outside air via the vent filter?

[@ItchyKneeSon]

You could add those screens permanently to both back pop-out windows. Add curtains for stealth.

[@p.newsman]

🏆 McGyver certified! 👌😅

[@kevinfenn9672]

Thanks for the video

[@nicknelson9450]

In these days of ill-advised AI voice-overs, childish background music or sound effects and content with little value-add, this video was a breath of fresh air...pun intended. Someone who knows what they're talking about, has thought through how to present their (useful) information, and yet doesn't take themself too seriously. Nice work!

[@vinnyandrocky]

Good to know the air exit at the back. If we crack the front window open, it will affect the air path. So we need to close the front windows to make it works? Nice video, subscribed.

[@miken7629]

Seems like you have a hole in the back where the smoke came out. Why not find that hole and install a computer fan and use that as inlet

[@user-sn8wp2ux1y]

This looks like a fun project. What was the part number or link for the Toyota wire harness you got for this build?

[@paddledogs]

Interesting, 2 questions - do you have a link to the CO2 monitor and what if you just stuck fan on the air vent pulling in air that way then you should get air flow (think about when the van is off or 'vent' mode). Not sure if your van supports that but computer fans are pretty low current draw.

[@fransubaru]

Very interesting idea!

[@CharlesReedPi]

Me and my son are going to breathe all the air in this vehicle,* Child Services listens closely*

[@NomadByNecessity]

Lol.. my heart skipped 2 beats at that point! Hahahaha

[@CharlesReedPi]

@NomadByNecessity I can see why haha! 😀🫁

[@CoastGord]

Interesting info...

[@motorenbastler9289]

I installed a complete car ventilation box into my camper. I was worried it would pull too much energy so i was afraid of using it. Since i have my Victron Solar charger i could figure out it pulls 30 watts on first fan stage. this way i could run it for 30 hours on my 100ah Lifepo battery and 15 hours on a lead acid battery.

[@alecmorrow3764]

Hello! The detail you go into is amazing. I am in my 2008 Sienna and thinking this would be a great idea. I just checked and have one of the wiring harnesses with 2 leads. Do you think the speed knob acts and a potentiometer and my blower accepts steady DC (with no PWM)? Would you expect my blower input to be 5V or 12V. Thanks for your time!

[@SemiSeriousLabs]

Hey, I just found a very helpful demonstration: kzbin.info/www/bejne/gZu0YYOBec6Fetk It looks like the lowest speed setting in his example is 5V. That or else 6V should be pretty easy to find in battery sizes.

[@markb3326]

Isn't there a flap that shuts when you choose recirc or car is powered down?

[@bryanst.martin7134]

There are vents in every vehicle. Hidden, but there.

[@neilmckay8649]

How about air quality in the sleeping area, with a privacy curtain in place?

[@benels54ven45]

I once tested the energyconsumption of a car-fan . On full speed it was about 140 watts..... way too much

[@ipsylon7297]

Smart.

[@ssteele1812]

Could you replace the ryobi battery and voltage converter with a portable power station with 12v out? I know you were using what you had on hand. Im just curiousif you could get more run time and use somwthing that some van dwellers have on hand.

[@SemiSeriousLabs]

Yes, and that would be better. I know some of my power gets lost during the voltage step down stage, and yours wouldn't need that.

[@tveten82]

PC fans in the rear of the car. Where the smoke leavs. Blowing out of car.

[@sbrownproductions]

Does that PWM pulse at 5V or does it pass through the voltage from the VDC source? I know you found 5V on the pulse, but I don't see dropping anything to 5VDC...

[@SemiSeriousLabs]

Good catch. I shouldn't have assumed the output was 5V. The output is the same as the input voltage. So maybe adding a resistor would be safer.

[@EvanBlack11]

Would this same items work with a Caravan?

[@SemiSeriousLabs]

Not exactly. It looks like most years of Caravan use a blower motor resistor instead of controlling it with pulses. That means your motor only has two wires and should be really simple to run. But what's the easiest way to run it at low speed? Maybe try running it directly with 5 volts, which is easy to get from a USB power bank.

[@EvanBlack11]

@@SemiSeriousLabs Brah this is prob the most helpful YT reply I ever gotten thanks. 🙏🏽

[@petersoakell6950]

Great. Subbed)

[@baldyetichronicles]

Uhm, how do you keep the fresh air vent open when the key is off?

[@stig]

where's the ten foot long spring loaded sledge hammer video please

[@avamaria8447]

I'll stay with cracking the windows

[@Rick-qf5de]

Wow the air quality was bad quick.... Imagine trying to hide from a fart....😮

[@goclunker]

Cars are not airtight. You're welcome.

[@troywhite6039]

Where can I buy that air quality meter??

[@cccmmm1234]

While CO2 has increased you have nowhere near used up the oxygen. Your body will operate fine with about 5x as much CO2, no problem.

[@lilliancalvert3800]

What model van do you have?

[@HesamSimin]

great

[@nyrubin]

I've slept in my car for 8 hours once, didn't run out of oxygen

[@justcommenting4981]

Are you an electrician or mechanic by trade?

[@jfloydsea]

Find a female gender plug and build a y-splitter so you don’t have to swap plugs constantly.

[@remog38]

So intersting thanks

[@nyrubin]

Now can you do another video where u hack the AC and run it off a power station lmap

[@NoelG-IRE]

Adding a roof vent to a van adds value. Don’t know why you think it’s destructive and somehow reduces the value. If it’s done right it’s fantastic. Even a basic roof vent without a fan would be better than pulling half the dashboard apart and ordering a heap of special parts to make it work. Just because you can, doesn’t mean you should. Will your version work? Yes. Is it a good solution? Absolutely not. Glad you posted it though as it is a good deterrent for others not to try it.

[@peteroffpist1621]

Buy a Tesla, Tesla has camper or dog mode. Climate control nice and warm in winter or cold and fresh air all night long in the summer.

[@antontsau]

Too complex. First of all all this in 21st century is based on digital controller, starting from $5 arduino. It will generate pulses and monitor/control anything you wish - battery voltage, state of native signal from car systems (so switch off and do not alter any usual fan operation), all air vane controls, time of day, set timer, whatever. Second - all these systems begin from secondary battery system installation. Other way it always ends up with flat main battery unable to start the engine.

[@RA-II]

Your car is NOT air tight.

[@topcheese2889]

Or just crack the window

[@loveasapologetics]

TLDR: uses vehicle’s manufactured exhaust/AC feature with auxiliary power or power monitoring.

[@veganpotterthevegan]

Window covers aren't stealthy either. Everyone knows when someone is sleeping in a car. Just park where you're allowed to park/sleep overnight.

[@wompstopm123]

what is a dude that already has kids doing stealth van camping? did you get divorced and your wife got the house ?