Roof Computer fans instead of a fantastic fan?

[Lance22]

So I recently put 4 100 watt pannels on my minivan and now 80% of the entire roof is just pannels. I do have two different spaces that is about 2-3 inches between pannels (pannels are attached to steel angle then mounted to the roof rails via U bolt so this gap was needed) Plus I have some space in front but might be getting to close to the windsheild so might be a bad idea...

But I was thinking about what impact would it have to put in say 4 small fans like USB computer fans and I would just run them all day (likely if I could set them up on a timer for daylight hours plus a bit extra at night. I have the solar easily. I just don't have the space for a fantastic fan. I was orgionally thinking of putting in 2 fantastic fans but I I crack the front windows all the time and 4 small USB fans in the roof blowing out air wouldn't that be like having one fantastic fan?

Thinking I'd get like 4 4inch fans that that be about the size of a fantastic fan. Plus with my current layout having more of a strip vs square fan would work better as air could flow in the gap between pannels.

I'm just brainstorming so will make sure I find something more waterproof but just in general has anyone ever used a "computer fan" or a USB fan installed into the roof? I've thought about using them in the side windows but the added stealth for having them on top and being easy to drive with them in place constantly is more desireable.

Thoughts?

 

[eDJ_]

Here is how I've been approaching it. At Lowe's you can buy strips of rain gutter guards. These are perforated vinyl (like siding) with screen wire bonded to it. It's long enough and rigid enough that it can be cut to conform to the upper part of the front door windows and be cut to fit into that space. By itself one on either front door with rear windows that fold out (with screens made for those) will provide for natural ventilation. As air coming in from the rear windows will flow forward on a gradual upward plane. The warmer air flowing out will draw in outside air thru the rear door windows. OK

These vinyl rain guards come in brown or white.

With a couple of computer fans mounted on the inside of each of these screens (total of 4 with a switch to run 2 or all 4) you may get the ventilation you want. How you wire them will be up to you.

 

[Lance22]

Yea, but I'm a city dweller so I want the stealth.

However I do think I might try using that method next summer when I am living in the minivan again. If I were to be living mostly on BLM lands Id say that work just fine. However I work a retail job that pays me about 20.50 an hour so I want to try keeping it for a few more years making as much as I can, if not even longer who knows.

you know...

I think I would try using plexiglass and putting in chrome-painted fans or better yet actual metal looking fans that are usb which would pop with my Honda Odyssey chrome molding.

 

[bullfrog !]

Holes, even ones filled with screws in the roof almost always eventually become a way for water to leak in. Just saying maybe consider ducting air out through a slightly open window covered by a rain shield by a fan mounted in or on the headliner. Complicated but so is the concept of stealth! Lol!!!

 

[maki2]

Always stop to visualize EVERYTHING from A to Z when you get ideas such as this.
You would need to create a curbed frame to mount them into. Water and rain can move sideways while you drive down the road or even when camping in strong winds. As you are not going to have any external cover you will need to use wet location equipment and waterproofed wiring connections. There is a potential for condensation to develop on the underside of the panels and drip down onto your equipment.
Of course you will also need insect screening and that will reduce the volume of incoming air. The fans and the screening will need to be made removable from the interior for regular maintenance to remove dirt and insect debris. You will also need to provide an insulated cover on the interior side of the roof opening.

It is possible to implement your idea but you have to make sure you think all the possible precautions that are needed to make it work. I have not covered all of them, I just did a quick mental visualization of the installation to reveal situational issues that need to be considered.

 

[rruff]

I was orgionally thinking of putting in 2 fantastic fans but I I crack the front windows all the time and 4 small USB fans in the roof blowing out air wouldn't that be like having one fantastic fan?

A typical 120mm computer fan will flow ~1/20th of the air that a Maxxfan does.

You can mount normal RV fans on their side. I think this would be simpler, as you'll need to figure out how to seal and cover the computer fans.

 

[rruff]

Another consideration regarding fans is how well they perform against an adverse pressure gradient. I couldn't find this info for either option in a quick search, but if you want them to function when driving, this will be important. I don't think an open window can be counted on to pressurize the interior at all, you'd need something that gives you a "ram air" effect. Both the top with a vent open to the back, and a rear mounted vent would usually be exhausting into low pressure air which will help.

 

[bullfrog !]

Any opening you cannot seal will fill the interior with dust on most dirt roads in my experience. I had 2 rear facing vents on the rear wall 4” in diameter of my camper that I forgot to close that completely covered the interior with fine dust after less than 5 minutes on a dirt road!

 

[eDJ_]

We used to have a member here named Stearnwake. His solution (addressing stealth) was to cut holes in his back door behind the license plate, which mounted on his door, to install a couple of computer fans together.. He was considering getting a door mounted spare tire carrier so he could install two more fans. The fans would be on the inside of the door and to secure the holes he could use that magnetic plastic sheeting painted the same color as his rig. So when traveling, raining, etc....he could place the magnetic sheets cut to cover the holes for the vans. These would draw in cooler air and with the front door windows lowered a bit, push out warmer air at the ceiling.

I see a lot of vehicles with those plastic rain guards mounted on the doors so that rain can't blow in when the window is rolled down an inch.

So you may think about that to see if it could work for you.

 

[jonyjoe303]

I use a small 120mm cooling fan (about 1 amp) to exhaust air out of my van through one of my roof vents, this fan is located next to my solar charge controller which gets very hot during the day. I also use another 120mm fan to exhaust the hot air from my 12 volt fridge exhaust vents. I exhaust this through 4 inch flexible ducting out the side of my van.

To bring air into my van I have a 14 inch vortex roof vent (3 amps on high), this fan is right under my solar panel, I removed the vent cover and use the solar panel as a cover to keep the rain out.

The roof vent I only use to feed air into my swampcooler through flexible 4 inch ducting. If I wanted to I could just use a 120mm fans for that since I always run the roof fan on low (about 1 amp). The air coming through the roof is usually cooler and the cooler the air before it goes into the swampcooler the better the cooling effect.

Another option is to buy a car radiator fan for 30 dollars and use that through a pwm motor controller, those move alot of air and are cheaper than a fantastic fan. A fantastic fan is just a car radiator fan that is speed controlled to only use 3 amps. An 8 inch car radiator fan without a speed control will use about 6 amps, there are also smaller 6 inch fans.

On extremely hot days you might need more than just the roof fans. They will only bring hot air into your van.

 

[maki2]

I see a lot of vehicles with those plastic rain guards mounted on the doors so that rain can't blow in when the window is rolled down an inch.

So you may think about that to see if it could work for you.

There a linear 12v fans made for cooling computer racks. That might be a possible combination of powered exhaust to use with the rain guard venting hacks. They would exhaust air to the exterior. I am not sure about reversible direction options though. It would require more investigation than I am willing to invest time in as I am not in need of such a cooling scheme.

 

[eDJ_]

Orion Fan Company makes a 12 vdc reversible 120 mm (5 inch) high speed fan that can deliver 146 to 115 cfm of air. Two of these mounted behind the license plate on the rear door of a Van (for an example) could deliver 292 to 230 cfm of air into or out of a Van. These are ball bearing fans with a 70,000 hour life expectancy rated at 10 watt draw maximum.

As an example, a small ceiling mounted bathroom exhaust fan generally moves 50 cfm. These Orion fans create about 50 dba sound level. (about the sound level of a quiet refrigerator) Two of these would move about 1/3 as much air a minute as a Fan-Tastic Fan, but would be much quieter

Orion OD1238 12 volt reversible

Orion OD1238 spec sheet

OD1238 12 vdc fan at Amazon

There may be less expensive sources for these fans. Also they may be a tight fit if mounted on the gutter guard screens I used on my rig as shown in post #2 above. ....but it could be done.

 

[LargeMarge]

So I recently...Thinking I'd get like 4 4inch fans that that be about the size of a fantastic fan...

.
1 -- Hydraulic flow (air is a thin fluid) doesn't follow a linear progression.
A 4" pipe can flow many times more than a pair of 2" pipes.
.
The problem is friction at the boundary layer.
Let's look at a river:
Near shore, water speed barely chugs-along compared to the middle of the raging torrent.
A similar sluggishness happens at the bottom of the river and around obstructions such as boulders.
.
A 4" fan only moves a slim cylinder of air through its center.
A 12" MaxxxAxxx fan moves a geometrically ('statistically significant') bigger column through its center.
.
.
2 -- In our ExpeditionVehicle, we mounted our windows on the upper wall near the ceiling.
In addition to gathering natural light to reduce ceiling-shadows, airflow cleans-out pockets of ceiling stagnation, encouraging interior odors and humidity to enjoy the GreatOutdoors©.
.
.
3 -- Although we use a portable fan facing the bed for bed activities during warm weather, that is a brute force alternative to working with natural breezes.
.
Similar to vanDwellers moving to warm regions during winter, we prefer the least amount of equipment to maintain.
Sure, we could pay-camp [shudders, nearly horks] with 'hook-ups' (not the 'funny-business' kind, sadly), and run an air-conditioner 24/7/360°, but that would defeat the nobile purpose of a mobile home on wheels.
.
.
All that blathering, and I am still leery of punching/poking/sawing/chopping Holes! In! The! Roof!.
And I acknowledge I could be wrong.
Your project might just be the cat's knees, the bee's meow, conveniently solving decades of consternation amongst sweaters and fumers...
... and the shower-every-month-whether-I-need-it-or-not crowd.
.
Adding an additional layer of valuable social importance to 'dispersed' camping.

 

[townline]

So I recently put 4 100 watt pannels on my minivan and now 80% of the entire roof is just pannels. I do have two different spaces that is about 2-3 inches between pannels (pannels are attached to steel angle then mounted to the roof rails via U bolt so this gap was needed) Plus I have some space in front but might be getting to close to the windsheild so might be a bad idea...

But I was thinking about what impact would it have to put in say 4 small fans like USB computer fans and I would just run them all day (likely if I could set them up on a timer for daylight hours plus a bit extra at night. I have the solar easily. I just don't have the space for a fantastic fan. I was orgionally thinking of putting in 2 fantastic fans but I I crack the front windows all the time and 4 small USB fans in the roof blowing out air wouldn't that be like having one fantastic fan?

Thinking I'd get like 4 4inch fans that that be about the size of a fantastic fan. Plus with my current layout having more of a strip vs square fan would work better as air could flow in the gap between pannels.

I'm just brainstorming so will make sure I find something more waterproof but just in general has anyone ever used a "computer fan" or a USB fan installed into the roof? I've thought about using them in the side windows but the added stealth for having them on top and being easy to drive with them in place constantly is more desireable.

Thoughts?

I have thought about Computer fans. Seems they are high quality motor wise.

 

[tx2sturgis]

Back in year 2000, I installed 2, 4 inch computer fans in a roof vent cover, on my old Class A, and they worked, but they are not weatherproof so eventually rain, dirt, dust, and debris will find its way into the inner workings of the fan motor unless you can find a configuration that is not subject to the elements.

If you don't have the room for a 14 inch fan, maybe you do have room for an 11 inch fan, sort of a fantastic fan 'mini'.

The 11" roof fan I installed on my P/U camper shell is a 3 speed with reverse function, and the motor is weatherproof just like a fantastic or maxx fan.

This is a Hike Crew brand...and I notice they now have a single speed, reversible, for about $65 on Amazon. That seems very affordable.

https://www.amazon.com/Hike-Crew-Motorhome-Exhaust-Garnish/dp/B09JF79XYM?ref_=ast_sto_dp&th=1