Which Air Conditioning Unit?

[BGD]

Hi Guy 'n Gals - Time to pick you collective brains again please.

 

 

 

We've got an old (1994) A-Class motorhome: an Ariel Autostar, about 6.7 metres in length.

We live here in Spain, and it gets hot (very hot, stupidly ridiculously hot) through the summers.

 

I'm considering having a roof-mounted air-con unit fitted shortly and would love to hear the pros and cons in practice of the various types/sizes.

Price is an issue for us, so it ain't gonna be a "Rolls Royce" heatpump type thingy that gets our final vote.

I've been doing some research, particularly around the Dometic units.

 

 

 

 

There are maybe 3 Dometic models as possibles at present:

 

CA100. Smallest model in their range. Only does cooling, not heating (not a problem for us).

Cooling power: 1000 watts (3400 btu).

Power consumption: 450 watts cooling only.

Cheap, and small dimensions, but I'm worried that this will fall well short of the performance we need, as Dometic recommend it for MH's/Caravans only up to 5 metres length.

 

 

Dometic B1600. (Apparently this model has just been superceded by the "B1600Plus" for 2010), but my local dealer has a B1600 in stock and is offering to fit it, with 2 year warranty, for €1220 all in.

1500 watt/5200 BTU cooling; and has 800 watt heating facility too.

Power consumption: 650 watts cooling/800 watts when heating.

Dometic say this is suitable for a MH up to 6 metres length.

 

 

Dometic B2200.

2200watt/7500btu cooling; 1.2kw heating facility.

Power consumption: 910 watts when cooling/1200 watts when heating.

Dealer is offering to fit one of these for me for €1490 all in.

 

 

 

 

 

 

And so to my specific questions for you good people:

 

1. Anyone else got any of these units? If so, how well do they REALLY function on hot days/hot nights? Any pluses/minuses of a specific model that I should be aware of please?

 

2. Another factor for us to consider is that our tours (when we stay on sites with EHU) are around Spain/Portugal/South France.

Until now I've never taken any notice of the "trip-out" load that most such sites have....but I believe it is often a lot lower than on UK sites.

We've never had a problem in the past, and have used a small, two bar electric fire without "tripping" the site electrics.

But the power draw of the Dometic B2200 at 910 watts cooling/1.2kw heating does sound quite a lot......have other users with similar kit had problems with tripping out their EHU when on southern European camp sites?

 

3. If anyone does use one of these Dometic models (or indeed, any other model), did you have the optional extra 12volt DC power kit added, so you could operate the Aircon whilst on the move? If so, how effective is that 12 volt "whilst driving" option?

(I ask, because our MH is venerable, and doesn't have cab air-con, so if the Dometic unit was effective in real-world practice on 12 volt dc operation, I'd be tempted to have the Dometic DC kit fitted as an extra cost option).

 

 

 

Any specific advice/feedback from actual users of these (or other) Dometic models would be hugely appreciated........muchas gracias a todos.

 

 

[Guest JudgeMental]

we have a WAECO easy cool 1500 12v/230v. It works well and would not be without one for summer camping. Soft start, but you still need a 6 amp supply.

waeco have been taken over by Dometic and the 1000 model is a re badged Waeco unit. It is to small I would think for your needs get at least a 1500 or maybe a 2000 watt one...the bigger the better I would think. works OK on the move but our ford has v good cab air so dont really use it the inverter was a waste of money for us.

 

your quotes seem reasonable.

 

have you space near the cab to fit it? as you may remember recent thread where someone wanted primarily to cool the cab while driving it but ended up with it over the rear bed *-)

 

they are noisy! but if you can sleep on a plane you will be OK :D Seriously though you get used to it ...and I have a siesta in the van no problem. we leave it on when we go out in the evening and usually switch it off when we go to bed as hardly ever find it necessary to run all night....

 

Dometic B1600 looks a very good deal.... all in at slightly over £1000.

 

is that including 12v?

 

How much is the 1000 fitted? as may want one on next van (panel van)

[Brian Kirby]

Buenas tardes Bruce, I think Eddie's right, a good read on this link will alert you to a number of potential shortcomings, largely related to the competence of the dealer concerned!  http://tinyurl.com/2vlzdch

Do note the need to get the leisure and starter batteries upgraded if you go for the 12V DC power kit.  The appropriate upgrade in capacity is recommended in the kit blurb, all downloadable form Dometic's website.  As your van is "venerable" it may also be worth confirming the adequacy of the on-board charger, but also the alternator, since the effect of running the aircon while driving falls mainly on the latter and, if inadequate, battery charge state will fall en route, instead of it being maintained/re-charged.  Feasibility of battery upgrading is largely a matter of suitable free space and payload.

Reckon on about 5A (1150W) for an average site supply.  A few are lower, but not really worth planning on, IMO.  Quite a lot of sites give a costed choice, but you can't always guarantee to be able to select sites on this basis.  I assume the van has gas heating anyhow, so the heating load need not concern.  If you need it, you are already paying for the supply, and the capacity is adequate, use the A/C for heating.  If not, use gas.

So, the main problem, I suspect, will be cooling.  If you can run it while driving, your van will arrive cooler, so will need less cooling once parked.  If you can find shade, and as you are presumably already fairly well acclimatised - unlike us lillywhites - the B1600 will probably take a useful slice out of the daytime heat, but it won't cause condensation on the outside of the windows!  The 600W cooling load should leave a comfortable margin of capacity for the other electricity consumers, fridge, battery charger, idiot lantern, computer, and maybe a small kettle, without tripping the supply.  The thing, as Eddie implies, is to check the start-up loads, for which you will probably need to contact Dometic direct.  If that is heavy, the unit may trip a pillar on start, even though the running load is well within its capacity. 

Note that the one pillar that has the trips all locked away, will be on the site where your hook-up is also locked into the cabinet, and the office shuts half an hour before you switch on the A/C!  :-)  It pays to play safe!

If the more powerful B2200 model has an alternative operating mode, in which it can be operated with a lower power drain, that would be ideal.  Otherwise, I think the 910W load, likely to be higher on start-up, is too close for comfort to where many of the site supplies lie.  MCBs also age a bit, and can begin to trip below their nominal capacity, so that "5A" may turn out a bit shy of a full 5A.  Therefore, unless the running/start load on the B2200 can be reduced to about 800W, I think, just on grounds of practicality, the best option will be the B1600.  It may struggle a bit at times, but it ain't going to make you any hotter, is it? 

I would also check the availability of a forward mounting point, as the greatest heat gains, and so discomfort, come from the windscreen and this is where the cooling is most beneficial.  If the bed is to the rear, so much the better, as having that lot whirring away just above your heads will not be conducive to sleep.

Prices look good, though, but won't include the 12V kit or battery upgrades, for which you will have to allow extra.

[BGD]

Thanks for that Eddie - much appreciated.

 

I too think the 1000 is gonna be woefully under-effective.

 

The price quoted for the 1600 includes fitting and IVA (Spanish VAT) and 2 year warranty, but no, doesn't include a Dometic 12 volt DC inverter kit; so I would only be able to operate the air-con unit whilst on electric hookup. (Or pay about another 500 euros on top to have the Dometic "12 volt DC Kit 2" fiited too)

 

At the moment I'm leaning towards the 1600 unit, rather than the even bigger 2200 unit.....both on grounds of price, but also because the amperage draw of the 1600 unit is quite a bit less.

(I'm hoping that as a result it won't keep tripping out site EHU's in Spain/Portugal....I've heard on the grapevine that heavier amp-draw units do this a lot over here, but only via hearsay).

 

 

[BGD]

Thanks Brian - useful thoughts.

 

I suspect that in practice we're going to end up NOT adding the 12 volt DC inverter kit thingy. The MH is ancient, the alternator is ancient; and I reckon we can live without the air-con enroute.

 

So it's really going to be used whilst parked up on sites with EHU, so as I mentioned in my reply above to Judge, I'm rather minded to go for the 1600 unit with its lower amp draw (Dometic brochure says it daws 2.9 amps when cooling, rather than the 4 amp draw of the 2200 unit.

 

I don't know how much above the running amp draw the initial "spike" on startup is though.

Dometic brochure says the 1600 unit is fitted with a 4 amp delay fuse as circuit protection for campsites, and the 2200 unit is fitted with a 6 amp delay fuse, so I guess the initial "spike" startup draw must be lower than those figures.

 

 

[Guest JudgeMental]

And I forgot to mention the alternator would probably need upgrading......

 

I would go for the 12v kit or find your own 2000 +watt inverter and get an auto electrican to sort it, this may be cheaper. 2-3000 watt on ebay from under £200

 

The dometic/waeco inverters cost an arm and a leg

 

You will kill two birds with one stone this way......I cant imagine living on the Med without cab air

 

in over 3 years we have had no problem runing ours on sites

[michele]

Hello stranger we have the Dometic B1901 It was exspensive . Fan Bloody Fan Tastic.

We took it out of one van and had it re fitted in the second van.

 

Its on all day in the South Of France its Ice cold so much so that if you oen the door you get hoit by hot air .

We have never had any troubles Bruce however we have tripped a few switches .

Secret is dont try and use the Microwave TV and Air Con all at once if I need the Micro I switch off the Air Con for however long .

 

I would we would recommend it .Defo. :D

[flicka]

Hi BGD

No experience of Air Con Units, but thought a comparison would help

See links below for a guide to some UK prices (not installed) & a couple of other manufacturers.

 

Coleman units

http://www.mobilegas.co.uk/caravan-camping/air-conditioning/

Telair & Dometic

http://cart.coolauto-onlineshop.co.uk/index.php?p=catalog&parent=45&pg=1

http://www.power4motorhomes.co.uk/airconditioning.htm

 

Based on the info on the links, your installed prices look attractive v the UK, but would assume there is a larger market in Spain, so I would expect overthere to be competitive.

Your dealer should be able to calculate the optimum model(s) appropriate to the size of motorhome.

Have a look at http://www.air-conditioner-selection.com/air-conditioner-sizing.html

Although for housing the calculation formula remains constant.

Good luck

[BGD]

Good stuff, Chaps and Chapesses!

 

Any Electrickery people out there who can have a stab at whether a bog-standard alternator as fitted to a 1994 2.5 turbo diesel Peugeot J5 van chassis-cab (same as Citroen C10 and Talbot Express models of the same era), could cope with the load placed on it by having to run the Dometic 12 volt DC inverter Kit thingy, as we trundle along?

 

Where's Mott et al when you need them!

[Guest JudgeMental]

I would think it would not be good enough. have a look on the casing and see what amperage it is and have a chat with the installer. I dont think a bigger one is that expensive maybe £150? (that is a guesstimate)

[BGD]

Cheers Judge - I'll have a chinwag with the dealer in the coming days.....

[Guest JudgeMental]

conrad-anderson really know their stuff, and sell alternators as well, I would give them a call for some advice on specifics...

 

http://www.conrad-anderson.co.uk/airconditioning-refrigeration/air-conditioning/dometic-dc-conversion-kits.htm

[BGD]

Thanks for that

[Guest JudgeMental]

BGD - 2010-07-24 6:48 PM

 

Thanks for that

 

Mmm...6.48 pm (UK) Hangover? :D

[Syd]

We have the domitec 2200 on our caravan and find it very good, on low, in the evenings, one can easilly sleep through it, we have the 12 volt option too so the van is cool when we get to where ever

Turns your hot Spain into the North Pole in about 3 minutes flat, caravan is 22ft X 8ft

[BGD]

Thanks Syd.

 

When you say you have the 12 volt powering option....do you really ever run the air-con from your leisure batteries (via an inverter) rather than 220volt EHU?

 

I read somewhere that someone had done this and said that it emptied a 110 ah battery in about ten minutes..........

[Brian Kirby]

I think Syd must be powering the inverter from his car while towing.  You're right, if the inverter took its power just from the batteries, they would be flattened pdq. 

The Dometic 12V kit is quite clever, because it detects 12 power from the alternator, converts that to 230V power, and delivers that to the A/C while driving.  If you stop with the engine running, say at traffic lights, or in stop-start traffic, the alternator output drops, so the inverter kit starts taking power from leisure and starter batteries to maintain the supply.  When you speed up again, the full alternator output resumes, and it again runs the A/C via the inverter, while the kit diverts surplus power to re-charging the batteries - I think prioritising the starter battery.  This is why you need a supplementary leisure battery, plus leisure batteries in good condition, a good starter battery, and a healthy alternator with adequate output.  It all gets worked quite hard but, if all is in good condition, and of adequate capacity, it will not be over-worked.  Then, when you stop the engine, the alternator stops generating, the kit shuts down the 12V supply to the inverter and the A/C goes off.  When you plug into mains, the kit detects the 230V supply, and switches that directly to the A/C, which picks up again.  That, at least, is the theory, and is clearly what happens on Eddie's installation.  Poor old Passera's was comprehensively cocked by an incompetent installer, so never stood a chance.  You need an electrician competent in both 12V and mains electrics to do the installation. 

For what it's worth, I think it would be something of a false economy to install A/C in the van and leave the 12V kit off, because cooling the van whilst driving, even if the delivery point is less than perfect, is the second greatest benefit of the A/C unit (night-time probably being the greatest).  After all, at all other times, if the interior is oppressively hot, you can always go outside and sit under the ban-yan tree, or even your roll out umbrella if it's monsoon time!

[BGD]

Cheers Brian for that.

 

I'm struggling at the moment to try to justify the extra cost for the 12 volt kit, plus in all probability a replacement alternator, in order to get the air-con to work whilst in motion.

 

'Cos we're in Spain (ie bloody hot throughout the day, particularly afternoon/evening for about 6 months of the year) my rationale for buying an air-con unit is to cool the interior of the MH during the sort of 2pm to 8am period if needs be.

Typically, when we are trundling about, these are the times when we're not travelling but are on site. I accept that whenever we wild camp the air con just ain't gonna happen!

 

If money was no object, I'd for-sure be getting the 12 volt kit fitted, plus an upgraded alternator on top of the air-con purchase/fitting price.

But Kathy seems to have some difficulty in agreeing to this extra spend, when the additional cost is (in Kathy-currency), something above 30 pairs of shoes.

 

My tactical error was, of course, quantifying this extra cost to her......maybe you could have a word Brian; whilst I retire to a safe distance?

(You might want to request a last cigarette and a blindfold......)

 

 

[Syd]

Correct Brian but I also have a Stirling battery to battery charger fitted plus some other bit's and pieces, have ONCE run the aircon from the leisure batterys but not for very long as I know that it is a very heavy drain.

 

We usually stop about half an hour before we reach our final destination to put the 12 volt aircon on.

[Brian Kirby]

The problem (sorry challenge :-)) Bruce is, as I see it - with all other things being equal - as follows. 

Mornings are generally the coolest part of the day.  So, in the absence of A/C, your van will cool overnight so, assuming you are not in full morning sun, you will be likely to begin any journey in a reasonably cool van.  Blacktop heats quite rapidly, so air temperatures above roads are always a bit elevated, compared to general ambient temperatures.  Thus, as the day progresses, your van will always be in the hottest available place.  Add to this that the windscreen and cab side windows tend to be the only single-glazed openings in the vehicle, and windscreens tend to be large, and you have the maximum solar gains right where you sit.  Then, of course, you have that hot little engine in front of you, and its hot little exhaust pipe under your feet.  So, when driving, the cab will tend to be the hottest bit of a hot little van.  :-)

Next up, for most of the time it is being driven, the whole van will be in the sun (relatively few shady roads).  So, the sun heats its whole fabric, including the contents, as you go along.  In the absence of any cooling, by the time you arrive wherever, you are hot, and the whole van is hot.  You now plug in and stick on the A/C, which has first to cool the air inside the van - which it will achieve quite quickly - but, for the van to stay cool, it must also "suck" the accumulated heat from the van's contents and fabric.  Its only means to do this, is to keep pumping in the cold air.  If you turn it off prematurely, the temperature in the van will begin rising again, as the heat from the contents and fabric again heats the inside air.  Thus, because of the daytime heat gains, you have to run the A/C a for long time to get the van truly comfortable.  This you can do, but comfort will take time, and you may need to leave the A/C running all night just to prevent temperatures rising, as above, in the early hours.  How well that works for you will depend on your sensitivity to noise, on how much noise the unit makes, and on how close to your bed it is mounted.  Always the provisos!  :-)

Now, if you can run the A/C while you are driving you will start off, as above, with a coolish van, and the A/C will then remove much of the daytime heat gains, from whatever source, as they arise.  You will thus arrive with a cooler van, but more importantly, with its occupants, fabric, and contents cooler.  If you now plug in, the A/C will have to work less hard to maintain, rather than create, a cool environment inside, so will achieve comfort conditions quicker, so earlier in the evening, and so you may not need to run it all night.

You will immediately spot two potential shortcomings.  First, the sun has great power so, on really hot days, at the hottest time of day, the A/C will come second and the van will become warmer.  It will merely be cooler than would be the case in the absence of A/C: it will not be a guaranteed result, just a better result.  Second, if you get to an un-shaded stopping place where everything has been really sun-baked all day, the heat will (and does!) linger for hours after sunset.  This means the van will go on picking up heat from the environment even after the interior is comfortable, and the A/C may struggle to fully counter these gains.  However, in either case, with the van interior cooler on arrival, not only will you feel fresher, but the van will start its static period cooler than if the A/C were unavailable when in motion.  So, in both cases, what you can achieve will be an improvement, but can never be guaranteed to give a perfect result, especially under extreme conditions.  To achieve that, you'd need to tow the A/C kit behind you on a trailer!  :-D

That is the factual argument (subject to my understanding), but whether the benefits are truly worthy of the cost, is obviously a personal judgement.  Since the kits are available and can be fitted at any time, why not suck it and see with just mains power, and add the 12V kit later if you come to think it may be worthwhile?  That, at least, would spread the cost, and would give an opportunity to assess the effectiveness of the kit before spending the extra.  If the dealer understands you may wish to do this, he should be able to arrange critical wiring etc so that it is appropriately placed for when, and if, you add the kit.

[Guest JudgeMental]

I think to not get the 12v is madness myself as you have no cab a/c. I could live without a/c on site, just use a couple of fans for instance, but for driving no way! been there done that never again! ;-)

 

(buy the mrs a box of different colour flip flops)