Help sought - Positive Air System (Dust Excluder) for RVs

[gavinwibrow]

I've been thinking about a number of positive air system options for the caravan, including already drawing on goingbush's extensive knowledge. [thumbsupbig]

There is a firm in Perth that make what looks to be an excellent unit at about $2K, so given I'm only looking at intermittent use, I'm searching for something a bit simpler and cheaper.

I've done some research on the possibility of using marine bilge air pumps, but suspect they have limited capacity to push against an almost closed system - ie they are designed more for pushing air directly to the outside through non restricted areas and without filters.

Then this mornings thought - I already have an a/c fitted, so could that not be adapted to run on fresh air setting to provide the required positive air pressure to exclude the dust entering on gravel roads etc? Might even be able to turn the unit on and off from the tow tug as required. Probably mean more frequent a/c filter cleaning, but given the infrequency of need, can't see too many other issues, so over to the wise. GO FOR IT!

I've asked the manufacturer to supply the a/c fresh air current draw, and at this stage I'm assuming being connected to the car might provide an adequate power supply possibly via an inverter (having just remembered that the a/c is 240V). I know my a/c operates at 180L/sec, which is actually pushing more air than the Lyons system at 120L/sec whilst drawing 6 Amps at 12V.

Anything to help us would be grey nomads on our quests?

[DiscoMick]

Don't know, but this was interesting reading.

https://www.caravancampingsales.com.au/editorial/details/dont-bite-the-dust!-58513/

[weeds]

Search goingbush posts, pretty sure he did it on his van

[DiscoMick]

Jayco and Lifestyle have versions of them.

[Blknight.aus]

I did it with an old holden carby air filter housing, and an elec fan of an AC condensor .

hole in roof, enlarge the hole in the filter housing screw and sealastic it down, fan in the middle of the filter, seal the bolt hole in the middle clamp the lid down and run 12V to it via a relay on the park light circuit.

Bonus points, put a second latch over relay on it and spin it backwards so it works as an extractor over your kitchen area. (and if you're really worried put a section of flex duct down into the sink so any water and left over dust gets trapped in the towel you leave in the sink.)

[weeds]

https://www.aulro.com/afvb/trailers-vans-and-campers/155201-show-us-your-caravan-camper-trailer-camping-trailer-7.html

In hear is some info on goingbush install

[gavinwibrow]

Don't know, but this was interesting reading.

https://www.caravancampingsales.com.au/editorial/details/dont-bite-the-dust!-58513/

Yep, done plenty of background reading, including this.

[gavinwibrow]

Search goingbush posts, pretty sure he did it on his van

I've been thinking about a number of positive air system options for the caravan, including already drawing on goingbush's extensive knowledge.

[gavinwibrow]

I've been thinking about a number of positive air system options for the caravan, including already drawing on goingbush's extensive knowledge. [thumbsupbig]

There is a firm in Perth that make what looks to be an excellent unit at about $2K, so given I'm only looking at intermittent use, I'm searching for something a bit simpler and cheaper.

I've done some research on the possibility of using marine bilge air pumps, but suspect they have limited capacity to push against an almost closed system - ie they are designed more for pushing air directly to the outside through non restricted areas and without filters.

Then this mornings thought - I already have an a/c fitted, so could that not be adapted to run on fresh air setting to provide the required positive air pressure to exclude the dust entering on gravel roads etc? Might even be able to turn the unit on and off from the tow tug as required. Probably mean more frequent a/c filter cleaning, but given the infrequency of need, can't see too many other issues, so over to the wise. GO FOR IT!

I've asked the manufacturer to supply the a/c fresh air current draw, and at this stage I'm assuming being connected to the car might provide an adequate power supply possibly via an inverter (having just remembered that the a/c is 240V). I know my a/c operates at 180L/sec, which is actually pushing more air than the Lyons system at 120L/sec whilst drawing 6 Amps at 12V.

Anything to help us would be grey nomads on our quests?


Thanks guys, but I probably didn't make it clear that I've already done a fair bit or research, and now specifically looking at whether reinventing the use of already installed a/c is a realistic option (or something similar, or something out of left field).

[Graeme]

From an electrical point of view, my understanding is that a portable inverter cannot be wired into a caravan's 240V supply, only an inverter that is designed to be hard-wired due to earth-neutral connection requirements. However re-wiring the a/c to be connected using a plug into a power point would allow the a/c to be run from a portable inverter.

Running an inverter producing 240V in a moving vehicle of any type becomes a safety risk in an accident.

[gavinwibrow]

From an electrical point of view, my understanding is that a portable inverter cannot be wired into a caravan's 240V supply, only an inverter that is designed to be hard-wired due to earth-neutral connection requirements. However re-wiring the a/c to be connected using a plug into a power point would allow the a/c to be run from a portable inverter.

Running an inverter producing 240V in a moving vehicle of any type becomes a safety risk in an accident.


Cheers. I might be better investigating 12V a/c if such things exist for bigger vehicle/RV spaces! Back to Google.

EDIT
Just found this on the Dometic site - asking for more info, as appears to apply to a specific range of a/c only
Using the air conditioner while driving?

To get the best use from an RV air conditioner while you’re on the move, a DC kit can enable mobile operation from the 12V vehicle battery.

[Graeme]

Perhaps they don't use 240V electrics, instead running on 12V or similar. My Waeco fridge can be powered by 240V but its compressor is low voltage AC at around 17V IIRC. A 12V kit could be useful away from caravan parks if one has enough solar power.

[DiscoMick]

Why does the dust suppression vent need to be powered? In the link I posted above there was discussion about scupper vents. All that is needed is enough air to go in to ensure the pressure inside is higher than outside.

[gavinwibrow]

Why does the dust suppression vent need to be powered? In the link I posted above there was discussion about scupper vents. All that is needed is enough air to go in to ensure the pressure inside is higher than outside.

It is all a matter of personal choice. I'm not satisfied with scupper vents and want a POSITIVE AIR SYSTEM that I can control in dusty situations. I've used caravans in various guises for much of my life, so been there done that.