My ventilation ideas... What can be improved?

[One Awesome Inch]

Okay so when I build my van interior I am going to endeavour to build it as much like a sealed box as possible... using silicone to fill in any gaps/seams wherever possible.

With the rear doors I am going to make one basically inoperable by building a wall right over it (but cutting a hole where the window is to let in daylight. I am going to insure it is transparent but still insulated somehow). The other rear door, the one with the handle/licences plate assembly, I will insulate as best as I can, but I will cut a 6 inch hole behind the license plate so that I can attach a 6 inch PVC pipe which will be my air intake vent. Utilizing the PVC pipe I can buy a cap to put on the end in the event I might want it covered... though the majority of the time I will want it open.

On the other end of the van I will cut a hole into the floor (maybe in the step of the sliding door) and use a PVC pipe as a second air vent. This will be the air outtake vent. I am going to try to keep the height of the opening of the vent the same height as the license plate intake vent.

I am wanting to place some sort of fan on the end of the air outtake pvc pipe to pull air out of the van and expel it outside.

My question is... what kind of fan should I use? I don't want it to be too powerful for concern of sucking the heat out of the van. Also, I want it be as small a power draw as possible yet still be effective in getting a good amount of air flow into the van interior. One of my main reasons for doing this is where I live in the PNW it is very humid... often above 85% and its not uncommon to be 95%.

So I need the ventilation to reduce humidity and get some good oxygen in there since I will likely be using some sort of propane heater (either Mr. Heater Buddy or Olympian)... I am aware that propane heaters add humidity to the air. Not good up here.

I was thinking of two choices:

1. These small 2 or 3 inch blade fans which run on 2aa batteries. I would recharge with these with one of those Goal Zero Nomad solar kits.

Or

2. A computer fan which can have a potentiometer attached to make the speed variable beyond off/low/med/high. I think I read somewhere that this can be done to make the speed extremely variable. Anyone know anything about that? If its a 5 inch fan I want to be able to set the speed quite low. Ideally power would come from the starter battery. I am not confident that the small amount of driving I do would be enough to keep a house/marine battery charged properly. I would buy the biggest starting battery I could get.

The only things I need electricity for are that one fan and my smartphone/phablet.

So any ideas about that computer fan with the potentiometer attached?

Overall, what are your thoughts about my ventilation ideas? What could be improved?

 

[One Awesome Inch]

Found this.... how to use pot to control fan speed:

http://www.ehow.com/how_6604169_wire-potentiometer-fan.html#page=0

Also found out that a standard 9 volt battery can power a computer fan for a bit more than 4 hours.



So it looks like the computer fan with a pot attached is the way to go.

 

[SternWake]

Silverstone FM121 is a powerful 120MM fan that comes with a speed control
Silverstone AP182 is a more powerful 180MM fan that can use less than half the fm121 on the slowest speed, but will use more than twice as much current at full speed.

The AP182 also does not like voltages over 13 when run at full speed. the hug gets very hot, and I employ a Voltage bucker to reduce voltage to the fan to 11 no matter what my battery voltage is.

http://www.amazon.com/DROK-Adjustab...sim_pc_85?ie=UTF8&refRID=0XT0PP2FQ9Y620FCC12N


Most computer Fans can be controlled with a PWM motor speed controller.

A simple potentiometer can only handle small wattage fans.

I can recommend this PWM motor speed controller as it has a 25Khz rate, which is inaudible to the human ear, where as other controllers are 14khz which causes a high pitched whine from some fans at slower speeds.

http://www.amazon.com/gp/product/B009HKFAIQ/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

This PWM motor speed controller did not work adequatley with the most powerful 120mm fan available.

http://www.amazon.com/gp/product/B00L5XEKOS/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

It would not slow it down enough to be useful. There are Non PWM versions of this fan and I suspect they would respond properly to this motor speed controller.

The Silverstone fm121 is among the most efficient fans available and variable speed via a dial, out of the box makes it a winner.

It uses about 0.09amps at slowest speed and about 0.4 amps at full speed, but these numbers and max fan RPM are affected by battery voltage.

The FM121 has no issues with voltages as high as 16 volts in my experience.

The Voltage Converter in the first link can also control fan speeds via voltage rather than pulse width modulation, but you need a small jewelers screwdriver and a good light and a steady to adjust output voltage.

best o Luck.

 

[Luisafernandes]

Just a quick note as I'm still reading through your post; you have your air intake behind the license plate and you air outtake by the side step. That won't work the way you're planing it because hot air rises. You hole, whichever is lower will be your air intake (unless you have a fan). [emoji6]

---

My advice regarding a fan: get a Fantastic vent or a MaxxAir. You won't regret it[emoji4]

 

[One Awesome Inch]

Good point Luis. Thats quite helpful to point out, I should have thought of that. The rear license plate has to be the passive intake vent because I dont want a fan or wires connected to it since it will be on the rear door.

Perhaps a solution to this is to just increase the height of the PVC pipe(attached to a hole in the floor) that the outtake vent with fan will be attached to.

Will that work?

As to the fantastic fan Maxx Air... I have consider that but there are two reasons I dont want to do that.

1. Stealth is super important in my case. I will be living in the same area in an urban neighbourhood near my job and kids. This has to look 100% like a regular van from the outside.

2. I live in an area where it rains a huge amount. I need the vent open the vast majority of the time to aid with reducing humidity and giving fresh air. If its raining I wont be able to have the vent open. If its a maxx air vent cover, it blows the stealth. Plus if the weather gets really cold I'd like to be able to drive into an underground parkade at the mall etc where it will be warmer... if even a little bit. The maxx air vent would likely make the van too tall to park in parkades.

---

Silverstone FM121 is a powerful 120MM fan that comes with a speed control
Silverstone AP182 is a more powerful 180MM fan that can use less than half the fm121 on the slowest speed, but will use more than twice as much current at full speed.

The AP182 also does not like voltages over 13 when run at full speed. the hug gets very hot, and I employ a Voltage bucker to reduce voltage to the fan to 11 no matter what my battery voltage is.

http://www.amazon.com/DROK-Adjustab...sim_pc_85?ie=UTF8&refRID=0XT0PP2FQ9Y620FCC12N


Most computer Fans can be controlled with a PWM motor speed controller.

A simple potentiometer can only handle small wattage fans.

I can recommend this PWM motor speed controller as it has a 25Khz rate, which is inaudible to the human ear, where as other controllers are 14khz which causes a high pitched whine from some fans at slower speeds.

http://www.amazon.com/gp/product/B009HKFAIQ/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

This PWM motor speed controller did not work adequatley with the most powerful 120mm fan available.

http://www.amazon.com/gp/product/B00L5XEKOS/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

It would not slow it down enough to be useful. There are Non PWM versions of this fan and I suspect they would respond properly to this motor speed controller.

The Silverstone fm121 is among the most efficient fans available and variable speed via a dial, out of the box makes it a winner.

It uses about 0.09amps at slowest speed and about 0.4 amps at full speed, but these numbers and max fan RPM are affected by battery voltage.

The FM121 has no issues with voltages as high as 16 volts in my experience.

The Voltage Converter in the first link can also control fan speeds via voltage rather than pulse width modulation, but you need a small jewelers screwdriver and a good light and a steady to adjust output voltage.

best o Luck.

Thanks so much for all that info! I want to be able to run the fan very slowly but still have the ability to crank it up.

In that case it sounds like the Silverstone AP182 is the better fit for me since I can adjust it to a lower power draw than the FM121, correct?

 

[SternWake]

While the 182 at slowest speed is 5 hundreths of an amp. The 121 is 9h UNDREDTHS. The 182 moves a lot more air on slow speed. And it will not enjoy battery charging voltages. The 182 can move 50 more cfm on high. And is a bit quieter on high. But it draws more than double on high.

Its a compromise i cant answer for you. Only give you data.

My biggest complaint is the white color. The 182 is more.difficult to clean. The 182 moves air in a straight column. The 121 has 4 hot spots that exit at wider angles.

My roof exhaust has two inline fans. Counter rotating. Arctic fan with an open case design. Both together move a lot of air.

Check other computer fan threads where i give lots more details

 

[Luisafernandes]

Good point Luis. Thats quite helpful to point out, I should have thought of that. The rear license plate has to be the passive intake vent because I dont want a fan or wires connected to it since it will be on the rear door.

Perhaps a solution to this is to just increase the height of the PVC pipe(attached to a hole in the floor) that the outtake vent with fan will be attached to.

Will that work?

As to the fantastic fan Maxx Air... I have consider that but there are two reasons I dont want to do that.

1. Stealth is super important in my case. I will be living in the same area in an urban neighbourhood near my job and kids. This has to look 100% like a regular van from the outside.

2. I live in an area where it rains a huge amount. I need the vent open the vast majority of the time to aid with reducing humidity and giving fresh air. If its raining I wont be able to have the vent open. If its a maxx air vent cover, it blows the stealth. Plus if the weather gets really cold I'd like to be able to drive into an underground parkade at the mall etc where it will be warmer... if even a little bit. The maxx air vent would likely make the van too tall to park in parkades.

---

Thanks so much for all that info! I want to be able to run the fan very slowly but still have the ability to crank it up.

In that case it sounds like the Silverstone AP182 is the better fit for me since I can adjust it to a lower power draw than the FM121, correct?

---

I too have to be stealth due to working in an urban area also. So far I haven't had a problem due to the fan. I do plan on installing a roof rack and solar panels in the near future, so we'll see how that goes.
Your point is valid regarding rain, though I can keep the fan open just enough to get fresh air/expel hot air,humidity. The only problem I come across is wind. If it's too windy I can't keep the fan open more than an 1/8 of an inch or the wind suction lifts the fan cover. I hear people with the Maxx fan don't have that problem. The reason Fantastic vents have one lift arm, Maxx vents have two.
I must say, the idea of having a vent behind the license plate intrigues me and I just might think of doing something similar in the future[emoji4][emoji106]

 

[gypsychic]

Check other computer fan threads where i give lots more details

I was just recently reading one, at the suggestion in another thread. This is very detailed. Great info there.