# 12v air con



## motman (Mar 11, 2009)

Hi,sorry if i do anything wrong,but am new to this forum and motorhoming,my question is can ac systems like waeco 12v supply cold air when vehicle is parked,our mh has 2x110a leisure batteries and am happy to add solar panels,our reason for wanting to do this is we intend to travel to france/spain in early autumn and have to take the much pampered westie who is now a bit elderly and likes sleeping more than walking,but we would like to be able to leave him in van for max 2hours, any help much appreciated


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## CliveMott (Mar 10, 2008)

realistly forget the waeco aircon unless you have a hookup or a generator. Its power requirement are too much for battery power.


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## ianhc (Feb 4, 2009)

Unfortunately most campsites abroad have limited amps available, and my own experience is that the A/C trips the hook up trip switches. I currently have a dometic A/C unit ( 240v) and also a dometic 130 generator built under the floor ( 2.6KW) , the unit can work on hook up when available ( subject to amps available ) and also on generator. The benefit is also that i can with a 100amp battery charger charge my leisure batteries up quickly (3x 110 amp units ), run the microwave, etc giving total independence. The Dometic generator uses a Honda engine so is totally reliable, uses a conventional car like exhaust sliencer system so is ultra quiet and uses very little fuel, also is transferable between motors, and because it lives next to the chassis out of the way is not obtrusive.


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## eddievanbitz (May 1, 2005)

ditto all of that

Eddie


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## carol (May 9, 2005)

CliveMott said:


> realistly forget the waeco aircon unless you have a hookup or a generator. Its power requirement are too much for battery power.


Clive they could fit an Efoy system couldn't they, instead of the solar panels, and that would at least top up their batteries - it depends on how much their dog means to them...

I believe you have one on test? Is it still going well?

It is something I would like to add, but perhaps the costs are still to steep for me, and to be honest with our 2 x 110 batteries (or 90's not sure which) and the 2 x 85w solars, we haven't had a problem, but we don't have a dog to worry about.

It would be for me a far better option for them. and of course if a subscriber you can get 5% discount from ODB

Carol

Edited - after posting I see that the OP is not a subscriber, so perhaps it is time to join £10 a year, and lots of special discounts for subscribers...worth doing


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## eddievanbitz (May 1, 2005)

Hi Carol 

The Efoy wouldn't even scratch the surface. 

Even if it could produce enough power to run a 2000 watt inverter, given the lack of fuel distributors and the recent disclosure that most insurance companies will only allow circa 5 Litres of Methanol to be carried, this would be a non starter unfortunately.

A generator is the only viable way of running AC when static and no mains in available. I wish it were different  

Eddie


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## carol (May 9, 2005)

Eddie, thanks for that, I hadn't seen anything about the insurance companies limit on amount of methanol carried.... oh well, can't afford it any way, and not so keen on a genny - they are great for people who have to have them for battery power for wheelchairs, or for medical reasons need them, but they are a wee bit too anti-social really.

But thanks for info

Carol


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## time-traveller (Apr 23, 2007)

I thought the original question was about a 12v A/C unit? How does an inverter come into the equation?



eddievanbitz said:


> Hi Carol
> 
> The Efoy wouldn't even scratch the surface.
> 
> ...


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## eddievanbitz (May 1, 2005)

time-traveller said:


> I thought the original question was about a 12v A/C unit? How does an inverter come into the equation?
> 
> 
> 
> ...


The Waeco AC/DC system operates from a 2000 watt inverter and a beefed up split charing system. The OP wants to be able to run the AC when parked up for a couple of hours. The battery capacity to deal with this would be unrealistic.

Eddie


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## Suenliam (Mar 22, 2006)

We have a waeco aircon machine and use it regularly on campsites in France. Touch wood (so who's superstitious?) we have yet to trip the campsite 'leccie. 

Sue


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## CliveMott (Mar 10, 2008)

The other requirement for having effective roof aircon is the necessity to be deaf!

How anybody can put up with the noise defeats me.

We had a wall mounted aircon in a Winebago in Australia and only used it to pre-cool the van while we were away. And only when on hookup.

How do others get on with this aspect?

C.


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## WSandME (May 16, 2007)

Whilst recognising the problems of a "proper" compressor air-conditioning unit, I note no-one has mentioned the 12v Evaporative units.

I have never experienced one, but from reading the specifications, and several user reports, I would imagine that they are worthwhile, reducing ambient temperatures noticeably without unbearable hits on battery or noise, and not requiring mains hook-up.

Has anyone here used one, and if so, what is your verdict?


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## Pudsey_Bear (Sep 25, 2008)

I have a domestic evaporative cooler, it's not too bad, big though, the size of an old TV on a stand, a bit loud and it needs to draw fresh air from outside, only uses 95watts, not sure of the spec on a 12v type, could be a goer, mounted in the roof, would like to know more before our lass melts while having a hot flush    

:big4: :signoops: Kev.


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## Pudsey_Bear (Sep 25, 2008)

Here's one


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## LandCruiser (Feb 12, 2006)

*12v AirCon*

We also have a pampered pooch who likes to be cool in warm climes and warm in cool climes !!

We have a Dirna 12v Evap AirCon (roof-mounted) which is just the job. It runs off the batteries (2 x 135Amp) and, when on site hook-up can be left going for hours to keep said Yorkie cool.

The unit was installed by Camper UK in Lincoln some four years ago and has been in use on extended trips to warm climes twice a year for those four years. Comes with a "remote" (for night or lazy use !) and is very controllable as to temperature and flow output.

It's low power (and low noise for the neighbours); it works - in France, Spain, Italy, Greece et al (it's been used in 40degC conditions) and keeps an 8M MHM cool through the night; it is also brilliant when travelling - stopping for a slow lunch or the supermarket shop - keeps the van cool for an hour or three without flattening the batteries.

To my mind, best of all worlds - you can use it anywhere - making you truly independent - and when on site it runs without disturbing fellow campers (I'm reliably told !). Do I sound as though I would recommend it - you bet !

A certain Westie wouldn't travel without it !!

Brian.


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## ianhibs (May 1, 2005)

I'm afraid that two hours will be just too much for your batteries. However, we frequently run ours for half an hour so that we can leave our dog in the van while we go into the supermarket.

Ian


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## CurlyBoy (Jan 13, 2008)

*aircon*

Hi, we had a roof mounted aircon on our previous MH, I used to start it on the inverter, and then with the generator running and hooked up, switch over using a double throw double pole switch, the generator was then easily able to run the unit if away from mains.
curlyboy


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## LandCruiser (Feb 12, 2006)

*12v AirCon*

The Dirna ByCool Evap unit has a 12v power consumption of 0.8A up to 8A (when running flat-out).

We haven't ever needed to use the maximum output when en-route and find the lower settings more than adequate when stopping for lunch or supermarkets (one to 3 hours duration) - only "knocking" around 10-12 amps off the batteries when in use for the longer period (quickly charged back-up whilst continuing on the journey).

The other practical advantage of the Evap system is the ability to use whilst on the move, keeping the "caravan" area cool for the pooch - the cab aircon just doesn't cope with 8m of motorhome !

The Dirna unit is shown here for info, with tech info tabbed: http://www.dirna.com/camper-ing.php

Brian.

Brian.


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## CliveMott (Mar 10, 2008)

Well, that looks about as good as you are going to get without a hookup or a generator.

You will be advised to use chalk free (distilled) water otherwise the unit will want cleaning frequently as it will scale up.

The technique has been around for years. It will give you a reduction of a few degrees, an amount dependent on the level of general humidity.

When its hot and humid these units don,t help much because the high humidity stops the water evaporating, and is the evaporation that causes the cooling.

Its your money.

C.


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## dannimac (Jun 8, 2008)

Very interested in this subject as Misty the Hairy Hound is not a fan of warm days at all.

Have had a look at the Evaporative one but have also seen the 12v one that Outdoor Bits has for sale (which doesn't require water and ODB says works better in humid situations).

http://www.outdoorbits.com/dc-airco-4400rm-12v-air-conditioning-p-534.html

Anybody have any experience of this? I'm new at motorhoming so not up on the technical side - how long would this run on your leisure batteries?

Ta

D


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## Autoquest (May 16, 2007)

Why can't you fit the CA1000 inverter version and run it with the van engine at idle?


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## CliveMott (Mar 10, 2008)

Without the engine running its a straight 25 amps from your battery during the day and about half that on average after the sun goes down. The unit is aimed at the panel van conversion, so those with roomier coach builts could find this unit not quite man enough for the job. But its a proper compressor cooler so will not be affected by humidity.

If you really want a decent aircon then get a mains one and also invest in the Dometic TEC 29 built in generator which is designed to power such equipment.

Or stick to good hookups!

C.


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## LandCruiser (Feb 12, 2006)

*12v AirCon*

Lacking in technical knowledge on the pros and cons of various systems, I can only offer an end-user's opinion on the Evap unit and - as mentioned above - we have been highly satisfied customers over four years of real use.

Our travels generally extend for periods of 6-10 weeks and have covered Spring and Autumn journeys through France and mid-Europe, Spain, Portugal, Italy and Greece. We seek out the sun and have experienced "highs" of 45degC (Seville and Jerez) and "lived" in temps constantly averaging 30degC plus for several weeks at a time. Throughout all of this, the Dirna unit has kept us cool and comfortable - and hasn't tripped any site electrics !

For us, the key attractions and benefits of the 12v Evap Aircon are:
a) Use it anywhere, including on the move
b) Fully controllable, including preset timer which lets you program-in for a 1, 3 or 6 hour "run" e.g., when going to bed - and adjustable by a small remote control from anywhere in the MHM
c) Cost - around £1100 when we purchased ours
d) Weight - around 20kg
e) low-noise when in use
f) cools-down by 15-20degC against ambient - and yes it does do that in the real World!

Yes, it uses water from a dedicated inboard tank. No, you don't need to use "special" water - Dirna recommend "drinking water". It is connected to the onboard water supply and auto "tops-up" from the main MHM tank, using site water fills!

The Dirna comes with an inbuilt water treatment "maintenance product" which comprises of a tank cap - which is changed once per year, when the unit is "serviced" = cleansed out with 20% solution of household soda bleach.
As it is a water circuit, you should drain-down for the Winter, of course!

So, for us, it is an ideal "low-cost" solution to keeping cool, without going for a "blizzard" product, needing substantive electrical power.

Cannot disagree with Clive on the ultimate solution - mains aircon and onboard gennie, but we neither had the money nor the payload (nor felt the need) to go for the blizzard job; The Dirna unit has been a really worthwhile "low budget", simple to keep and use "alternative", approved heartily by a certain Yorkie !!

Brian.


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## eddievanbitz (May 1, 2005)

Autoquest said:


> Why can't you fit the CA1000 inverter version and run it with the van engine at idle?


That unit is rubbish and was really only designed for small caravans

Eddie


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## pippin (Nov 15, 2007)

Something puzzles me about evaporative "airconditioning".

I had extensive experience of aircon on board the later ships of my career in the Merchant Navy.

The real benefit of aircon was the removal of humidity from the air.
High humidity is what makes you feel uncomfortable as the sweat does not evaporate from your skin.

It was generally accepted, even in the tropics, that to cool the ambient air by more than 10C-15C made going outside too much of a contrast.
Even if the outside air was 45C the aircon would only reduce it to 35C, which might seem quite hot - by UK summer standards!

It was the condensing out of the humidity plus the relatively small reduction in temp that really gave us the comfort.

Shipboard systems were inevitably compressor driven and in fact the condensed out water was very pure and was fed down to the engine-room.

Now, take your average evaporative cooler. 
Here I quote from the Dirna website:

_When a liquid evaporates, it absorbs heat-

The hot air from outside passes through a wet filter where the water is evaporated absorbing the heat and cooling the air.
The cooled and fresh air flows as a breeze over your body, so your skin gets cool quickly in an absolutely natural way. _

Now to my mind that involves adding moisture to the air.
The air might be a bit cooler but the killer sweaty humidity is raised.

Unless of course there are two air circulations (as in compressor aircon) which are not connected except by a heat (coolth) exchanger.

ie - The fresh outside air is pulled over the wet water filter and then over a heat (or coolth) transfer element before being expelled outside where the added humidity is of no consequence.
Internal air is circulated over the cooling element and passed back into the internal space cooler than it was. In the process, some moisture would condense out as well.

However, I do not think this appears to be the case with the Dirna system.

I have always been suspicious of evaporative coolers as advertised for domestic use.

Correct me if I am wrong.


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## LandCruiser (Feb 12, 2006)

*12v AirCon*

Hi! Pippin,

As I mentioned before, I'm unable to join-in technical discussion (= an incompetent !), I am merely trying to pass onto fellow MHMers (when asked) the end-user knowledge gained from four years extensive use of the Dirna unit.

However the Dirna unit cools the air, it works in practice! We don't feel or get "sweaty" when using the unit, wherever we've been in Europe; we have a pleasantly cooled atmosphere inside - as it isn't "blizzard" cold the contrast to outside air makes you feel comfortable, not sticky, or sweaty, just cool.

It is a long-standing bit of kit, originally developed (apparently) for resting/sleeping use on truck cabs plying across Europe (the tomato deliveries !); we've certainly noticed a good few in such use on our travels.

So, I can't explain how/why it works, but from these end-users viewpoints, "it does what it says on the can" and has done so for us, for a relatively modest price, anywhere we have been (with, or without site elec.).

Usual disclaimers - merely trying to offer actual user experience !

Brian.


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## motman (Mar 11, 2009)

*Thanks*

Thanks for replies,will investigate current cost of unit suggested by Brian,point taken about evaporative coolers but his reply suggests that unit works in real world and we will not be travelling in high summer,i don't no why but would feel uneasy about leaving pooch in mh with generator running,what if it stopped,been a mech engineer all my working life and you just never know when somethings going to break,if any one needs any questions answered about mot's, i am an authorised tester and own a mot station,once again ta


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## dannimac (Jun 8, 2008)

Remembered that there was a previous post re an alert when it got above a certain temperature. It's Wooly's post on here:
http://www.motorhomefacts.com/ftopic-58640.html&postdays=0&postorder=asc&highlight=text&start=10

Something to think about - Misty Girl thinks a Scottish summer is worth panting over!

D


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