Aircon

[Brambles]

Yep! , Brian, no correction needed there but a bit vague on why you need 250 Ah battery capacity. It is also to do with the discharge rate batteries can with stand for x period of time without local over heating the plates or being damaged in other ways. Baicaly most leisue batteries wil with stand a discharge rate of c/5 until flat. But for short periods C/3 is ok so at 80 Amps you would need a capcity of 80 x 3 = 240 Ah capacity to cope with 80 Amps sdcharge current and nott too great a drop in voltage.

 

Gel batteries can cope with a higher rate of discharge and some easily with C/1 inother words a 80 Ah battrey could give you 80Ah for short periods. If continuous it would need the temperatire of the battery to be monitored and dicharge be controlled for safety. Fortuately if you attempt with an Invertor it will drop below its specified supply voltage and it will drop out and switch off. What is happening with Judge I suspect when he says it cyckes on and off. The batteries just cannot supply 80 amps at a solid 12 volts. The invertor in the aircon case also monitors for the voltage dropping and switches off so it preserves plenty of power left in the batteries so you cannot arrive at your wildcamping site with a flat or low charged battery. So it looks like they have thought about this from a few angles and come up with a required capacity of 250 Ah, but in many cases you will get away with lower capacity with hi spec batteries.

With a 100 Ah gel of high quality, I would think it should work and be sufficient, but, and a big but, it may not do teh batteries much good,it is only in theory it will work.

 

I am just thinkling back to a tail gate system I worked on for lorries, it had a 2Kw 24 volt dc motor and it was absolutey killing 300 Ah batteries, two in series. The discharge rate was below C/5, but when exide recommended changing to calcium batteries they coped as C/3 was acceptable. running at c/3.6 was above this and no longer were the batteries failing.

[Brambles]

tonyishuk - 2010-06-11 5:18 PM

 

I do not want to muddy the waters more than they are already but if might be wise to consider a Battery to Battery charger to aid the charging of the leisure battery when the air con has worked, but drawing the charge in the leisure battery down.

 

Basicaly a B2B charger uses electonics to boost the charge in the leisure battery.

 

I started a thread http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=19685&posts=16

 

which gives a description of what goes on.

 

If I have mudded the waters, I will withdraw my stick from the pond and watch the ripples ;-)

 

 

Rgds

 

Actually this is a very good suggestion, but not necessarly for quite the resons you believe. !st of all teh aircon invertor kit does preserve charge n teh batteries, whe it detects the voltage dropping toomuch it wil stop powering the aircon. So basically it wil only fill infor shot pwriods so only a certain percentag of power/capacity can be removed from batteries. Say 10 to 15% at a guess is alloed to be drawn, probably less. Howeverif wild camping many will want this extra bit of capacity available for a long stay.

 

The problem is it is te lat 15% or so of capocity whcih is hard to put ito battery, it takes quite a few hours at 14.4 volts, and in some cases could be 8 to 12 hours. So teh alternator wil charge quickly up to 85% full but then take ages to fully charge. The B2B being basically a 4 stage chargeris able to take the 14.4 volts from teh alternator and boost this to a higher voltage to pump in more curremt to the battery ad charge the remaining 15% much faster. It also equalised the battery cells better. Taking periodic high curremt docharges really does unbalance the cells. Especially as teh end cells can run cooler than the middle ones as larger area to dissipate heat generated. All this means they work differemtly and the cells beome unbalanced. The B2B will correct this imbalance a lot faster in a much shorter time than an alternator or basic mains hook up charger.

 

Hence why I suggest it is actually a very good idea especially if you need every ounce of power in your batteries when wild camping. But then again many who need every drop of energy have solar panels fitted which of course will help.

 

Mudded the waters? Not in the sense it is totally of teh mark and rubbish, as I said brilliant idea an has adds a great bonus, however I suppose it does mud thr waters for someone who deos not have clue what the heck we are talking about. Sorry , think I have mudded the waters as well now for thr KISS principle. I shall shut up now,

Jon.

 

edit - p.s. I thought when I got a new monitor my spelling and typos would improve..not at all. Sorry for typos above -- next week I get my new specs - maybe they will help me see what I type.

[Brian Kirby]

Brambles - 2010-06-11 5:19 PM Yep! , Brian, no correction needed there but a bit vague on why you need 250 Ah battery capacity. ...........

On the above, it was merely because it is what Dometic recommend for that particular Kit, inverter, and A/C unit - for use while driving.  If the battery capacity is not in conformity with this recommendation, and for some reason the A/C fails to perform as expected, I suspect the first culprit to be blamed would be failure to respect their recommended battery capacity.  So, it just seemed safer to take that as read, and meet the requirement.

Re the B2B suggestion, the Dometic Kit is stated to link the starter and leisure batteries, and to share the load between them when the alternator output is insufficient to feed the inverter.  In this case, is there not a risk that a B2B could interfere with the Dometic controller in some way.  Two control systems looking for different control parameters at the same time, and so simultaneously trying to impose conflicting operating regimes?

BTW, was that a pass, then!!  :-D

[armstrongpiper]

May I just add a word about the Max Gross Weight of the Vehicle? All this extra kit means a lot of Kgs added, so don't loose sight of the effect on your Payload.

 

 

Neil B

[Brambles]

Brian Kirby - 2010-06-11 6:09 PM

Brambles - 2010-06-11 5:19 PM Yep! , Brian, no correction needed there but a bit vague on why you need 250 Ah battery capacity. ...........

On the above, it was merely because it is what Dometic recommend for that particular Kit, inverter, and A/C unit - for use while driving.  If the battery capacity is not in conformity with this recommendation, and for some reason the A/C fails to perform as expected, I suspect the first culprit to be blamed would be failure to respect their recommended battery capacity.  So, it just seemed safer to take that as read, and meet the requirement.

Re the B2B suggestion, the Dometic Kit is stated to link the starter and leisure batteries, and to share the load between them when the alternator output is insufficient to feed the inverter.  In this case, is there not a risk that a B2B could interfere with the Dometic controller in some way.  Two control systems looking for different control parameters at the same time, and so simultaneously trying to impose conflicting operating regimes?

BTW, was that a pass, then!!  :-D

Oh blimey! was not aware of thatm but of course it woudl have to because teh split charge relay relay would be closed for alternator to charge the leisure. The cable will not be capable of the 80 Amps and only a 40 Amp fuse. The invertor needs to draw power fron the alternator and the leisure batteries, starter being connected to the alternator menas by default the two gets linked when it draws power. It must have its own heavy duty relay and wiring from both.The B2B will gets its output shorted to the input. What effect it will have I am not sure, it will have protection built in but the end result I do not know. I imagine it will be fine, but...........???

[Brian Kirby]

What I really meant, Jon, is that this a specific adaptor kit, supplied by Dometic, to feed their roof mounted motorhome A/C unit via 12V when driving.  The kit (from their illustration) comprises the inverter, a controller, relays, and cables to make all (in Dometic's opinion) the necessary connections to both leisure, and starter, batteries.  I'm sorry if that wasn't properly clear, I had to rush off for me din-dins!  :-)

I appreciate that you are not advocating installing a B2B charger, but I think it would be wiser, as with the Dometic recommended battery capacity of 250Ah, to install the lot to meet Dometic's requirements (which I am sure is what the dealer will in any case do), and then prove it works satisfactorily within its warranty period, before making any ad-hoc modifications to the power feeds.

As this little lot will cost poor ? ;-) old Frank over £2,000, I tend to think the dealer should stick strictly to what Dometic specify, because any departure from that route might prejudice his come-back against the dealer, or Dometic, if it all goes pear shaped.  Always the optimist, eh?  :-D

[Tomo3090]

On this van we've got a Dometic 2200 system, and the last one, a Compass Avantgarde, a WAECO 1000. On both vans we have the inverter, under the front off side bench seat, connected to the vehicle battery and a socket for inverter use and a 240V fused socket for hook up on the side of the seat behind the drivers seat. The air con unit has a 3 pin plug on it. If we want the aircon on when we are driving we just plug it in the inverter socket and turn it on and it runs fine.

 

If we want aircon when we are hooked up we just swap sockets and it works fine there too, (assuming the sites power supply is up to it.)

 

If we are wildcamping we again use the inverter socket and just run the engine on tick over, "blipping" the accelerator first to get the alternator to kick in. Then turn on the aircon and away you go!

 

If we are off hook up, wildcamping say, we found that running the aircon for 10 minutes after the sun went down sufficient to cool the van to a nice level, then running it again for 10 minutes just before we went to bed, made it a nice temp to sleep. We had no complaints from a van about 10 foot away about the noise as it wasn't any later than 10.30 ish.

 

You just have to make sure you start the engine before turning on the inverter and of course turning it off again befrore switching it off! Our van is on a 2008 FIAT 130 X250 chassis and I have no idea what output the alternator is but it works fine.

[dwaviation]

Can I ask how you found the Waeco 1000? Did it cool the Avantgarde OK? and did you use Dometics own inverter or an eBay job?

[Passera]

Just an update following my thread.

I am assured that the dealer is fitting 2 brand new leisure batteries and a new starter battery. Also following Brians comment i am assured that the charging procedure will charge both leisure batteries and also the starter battery.

 

Will know for certain in 2 days time.

It seems the thread was a great help to me so again thanks to all.

[Guest JudgeMental]

Passera - 2010-06-29 7:34 PM

 

Just an update following my thread.

I am assured that the dealer is fitting 2 brand new leisure batteries and a new starter battery. Also following Brians comment i am assured that the charging procedure will charge both leisure batteries and also the starter battery.

 

Will know for certain in 2 days time.

It seems the thread was a great help to me so again thanks to all.

 

just make sure it works OK on tick over when you pick it up........Dont let dealer sit there reeving it to get it to work *-)

[Guest JudgeMental]

dwaviation - 2010-06-14 5:49 PM

 

Can I ask how you found the Waeco 1000? Did it cool the Avantgarde OK? and did you use Dometics own inverter or an eBay job?

 

I would be interested how Tomo managed with the 1000 as seems perfect for a Panel van...but they say its only for 5 metre vehicles and van is 6 metre :-S

 

we have the Waeco 1500 at the moment, and it seems the units jump from a light and neat 1000 watt to a much heavier 1500 watt and nothing in between

[Tomo3090]

The Waeco 1000 was absolutely fine. The Avantgarde 140 isn't a big van so we found it just right for the living space. We were in Granada in Spain and were on the site in the city and hooked up, so we left it on whilst we visited the Alahambra in May/June. After being out all day in the heat and bustle of the city when we opened the door of the van it was like entering a freezer! Fantastic!

 

We have had no problems with either of the units, the WAECO and now the Dometic, and I would recommend getting an air con unit to anyone who has the money, real estate on their roof and, not forgetting, the payload of their van.

 

My motto in life is if you can afford one why not have it! It's what I use to justify having the van in thr first place! :-D

[Guest JudgeMental]

Thanks Tomo...just looked up your old van and it is a 6.2 m coachbuilt? Sooo if the 1000 cooled that OK it should be fine in a panel van I hope......

 

it weights 18kg so nearly half that of 1500 units. Plus a sat dome and solar panel its going to get a bit wobbly anyway :-S

[Passera]

Well collected our first ever MH today after much messing about. 3 new batteries fitted 2 leisure and a starter.

As far as I am aware all were fully topped up. Drove down from the North for about 5 hours and had a short stop.The Aircon was on all this time as it was very hot travelling. Cant say the cold air was filtering through with any strength but we were in monitoring mode. Checked the control panel and the battery strength was one up from red. Continued for about another 15 mins and ac cut out. Stopped and battery light was now showing red.

 

Since hooked up and it is all working from mains OK.

 

Surely 5 hours operating in drive mode should not drain the 2 batteries. Will check again tomorrow but it really means driving around for a few hours to see the effect on the batteries.

 

Read the manuals but it really comes under the DC2 kit manual and it really only covers the cut out if no battery power is left. says it is design to operate when driving but no indication of performance in ths mode. It is also designed to intelligently use leisure and starter battery.

 

Obviously will speak to the dealer but any input from anyone please.

Before you ask not sure of battery capacity but must be suffucient and according to Dometic spec

 

[Brian Kirby]

I think the answer is that the alternator should have sufficient output to supply the A/C, provide some charge to the batteries, and run the fridge, while driving normally. 

With the A/C on, the batteries (but what capacity/type are they?) should only be supplying power when the engine is idling, when the alternator output could be expected to fall below demand. 

So, after 5 hours driving, you should have arrived at your stop with pretty much fully charged batteries.  But, how long did you stop, did you leave the A/C running while with the engine stopped, and did you check the battery state when you arrived, or just before you left? 

Do check that the mains charger is re-charging the batteries!

[Passera]

We stopped for about 10 mins. AC was turned off before killing the engine and not started again until we were underway. Checked battery several times in those 10 mins and always one light above red. 5 mins after resuming journey ac stopped and 30 mins later at destination battery was on red.

Interesting you say about the fridge as we switched this to 12v just before we started journey and noticed immediate clicking noise from electricity. The 12v light on fridge was flicking with the clicking. I think the engine was on tick over at the time.

Anyway after 5 hours light was still on fridge but not in any imagination was it remotely cold. Had it on 240v hook up overnight and it is now very cold. Batteries are now all recharged.

 

 

 

 

 

[Passera]

Dealer just said that 12v fridge just maintains at temp before switching to 12v. As it was not previously on then I guess this is why it never got cold.

 

The a/c they said the testing of the alternator showed it produced more power than was required e.g over spec. Suggested charging to maximum and monitoring.

 

Try to do this over next few days.

 

[Brian Kirby]

Passera - 2010-07-03 10:51 AM Dealer just said that 12v fridge just maintains at temp before switching to 12v. As it was not previously on then I guess this is why it never got cold.

This is fair comment, though it doesn't explain all the clicking you heard.

The a/c they said the testing of the alternator showed it produced more power than was required e.g over spec. Suggested charging to maximum and monitoring. Try to do this over next few days.

Al well and good, but you have new batteries that started charged, or at least not discharged, and ended discharged.  If the alternator was producing better than its rated output it should have been charging all three batteries, via the Dometic controller, plus driving the A/C via the Dometic inverter, plus running the fridge, and still have had power to spare.  It seems it ran the A/C O/K, and probably the fridge, but did not charge the batteries.  That it could do the former proves it was generating OK, that it failed to do the latter, suggests there is a fault in the installation of the Dometic controller/inverter, either in the equipment or in the connections.

What was the state of the starter battery when the leisure batteries read flat?  Was it flat, or fully charged?  If all is working correctly, it should also have been discharged - but possibly within a limit - as it is supposed to share duty with the leisure batteries when the A/C is running.

That the batteries re-charged when the mains were connected suggests they were present (;-)), and that the fuses are intact.  This leaves just a fault between the alternator outputs and the batteries, that is preventing alternator current charging the batteries, while it is able to run the inverter/A/C.

To me, this suggests a missing link of some sort - possibly a fuse that was removed when fitting the equipment and left out, an unfinished bit of wiring, or (unlikely) a dud charge controller.

[olley]

It could simply be that the alternator isn't big enough, the spec says 910watts power consumption, that's around 70amps add in inverter in-efficiency and that's 80amps , add in your fridge at say 10amps.

 

Now how big is the alternator? 120amp? That leaves 30 amps for the engine, sounds a lot but have you got cab aircon? the fan will consume maybe 10amps, engine battery charging, radio on, engine management systems, anti-lock and who knows what else. It might add up to more than you think.

 

Olley

[Passera]

Well it is true to say i have had a week of hell -surely MH is supposed to be enjoyable.

 

There are so many issues that it is difficult to see the wood from the trees.

To recap I have a 4 year old Lunar bought without a/c. On dealer advice Blizzard Dometic B2200 was installed with DC2 kit to give us a/c when on hook up and when driving (Dometics words in their manual). Important to us as we live in Spain.

Yes we did have an issue when travelling from the dealer whereby batteries appeared to drain but such is catalogue of problems (non a/c based) since then that has taken a back seat.

 

During our initial drive down we did hear a clicking noise when the fridge was in 12v and the led was flashing. This soon stopped. However we recently discovered the fridge led on 12v was not displayed and suspected the fridge was not working on 12v. A local fix it agreed after testing and said that when starting the motor all interior habitacion lights should be disconnecetd. Ours are not so therefore he suspected a relay issue. i mention this because as soon as i brought a/c into the conversation he thought that was too much of a coincidence.

 

I have run a/c on 240v for up to 3 hours with no drop in room temp i.e 25C at 6pm tonight and the same at 8pm. I have noticed that periodically a noise (would that be compressor or inverter?) kicks in and at that point good real cold air is emitted. This lasts for 30secs+ and then the noise dies down and for 3 - 4 mins air emitted is not cold. then the cycle starts again so no wonder the unit is not cooling the MH.

 

On 12v it may be the same story only it is difficult to test as keep having to go on a long run and so much trees about if you get the meaning.

 

I have spoken to many people about the general problem but i get the impression that no one knows in detail about these DC kits although i get feedback that the MH should cool down certainly after 2 hours on 240v.

 

I finally managed to get an e mail from Dometic having tried to speak with them 10 times (Can anyone ever speak with them).

 

Their reply included this extraordinary statement

 

"Please note that your cab coolers are for cooling the cab, the air con is designed for the living area, when stationary, you will notice around the air con (normally fitted in the living area if possible) a cool area, this will dissipate through the van, but when on the move, turbulent air can push the cooler air to the back, but also cool air sits at ground level, so hot air rises. This mean the area will cool from floor up."

 

Not saying it does not make sense but why are they marketing a product that states DC Kit will produce a/c when driving when it is failing to cool the driving or passenger area. maybe it is a play on words as it does produce when driving but not to the driver.

 

I also repeatedly asked about expectations in temp reduction and get simply no answer.

 

I paid 2250 pounds for this and am thoroughly dissolutioned with the product and to be honest wished i never had gone down the MH road.

 

We were to return to Spain on Monday but appears we will have to reschedule at a cost and have time at the dealers but I feel no one really seems to have a grasp of what to expect certainly as far as DC goes. Indeed the dealer say this unit is what Dometic recommended.

 

Everyome on this forum has been very helpful so far so always interested in reading your comments

 

 

 

 

 

[Guest JudgeMental]

Motorhoming is only "enjoyable" if you buy the right van

 

Dometics statement is far from astonishing and makes sense to me.

 

while travelling the system will be hard pressed to force refrigerated air forward to the windscreen unless fitted above the cab. where is it fitted exactly?

 

our roof a/c is in corridor above kitchen, between lounge and bedroom. It works very well in 35 deg + heat. but all doors and windows and reflective blinds have to be kept closed....this cannot be achieved while driving. I just don't get why people who travel in the med in summer buy a van without cab a/c

 

I warned you to try the system properly on dealers forecourt, and if it did not operate on tick over to reject it...the lunar is probably poorly insulated in the first place which cannot help.

 

I am guessing that you need a more powerful alternator...this has been suggested before, but you seem to ignore the advice on here and believe the dealer, now that is astonishing......

 

when the compressor kicks in it should not stop ...so the problem is with either the installation, or alternator or battery and not the unit i would think. so the dealers responsibility? I doubt that there is any thing wrong with a/c unit.

 

i would like to know where the unit is fitted please.

[Passera]

Judgemental

 

This is our first MH and bought on a budget. The Lunar was well rated in one magazine and i am not sure the van is the problem here.

We discussed our requirements at length with the dealer who full well new our a/c priority. They said they discussed with Dometic and this was the solution. It was not until we received vibes from someone we met about the a/c "limitations".

 

I raised this with the dealer as well as on this forum only a week before collection. We were again repeatedly assured that the planned system would meet our requirements.

 

We also went to great lengths to check out the dealer and only positive feedback.

Your comments about ignoring the advice of this forum are very unfair. On Brians advice I checked there were two new leisure batteries at 110ah each. Also on his advice I insisted that on charging the starter battery was in the loop.

Far from ignoring your advice on alternator I raised this with the dealer as you suggested and yes took their word that it was tested and well over spec. I have since been trying myself to obtain the spec and yes again via the dealer. I am also tring via Renault dealer. I am not technically minded and do not even know what one looks like.

 

Your suggestion to check on the dealers forecourt was also taken on board. I think you said the make it worked on tick over dont let the dealer rev it up. i specifically did this so far from ignoring i took your advice.

I actually printed out everything from the forum and tried to cover the points.

When I started the engine and switched on a/c it was functioning but I never dreamed that maybe it was not emitting cold air all the time and never dreamed the compressor was cutting in and out above the engine noise. Even if i had heard it I would not have understood the significance.

 

We had arrived at the dealers at midday to allow time to go through everything. There was a problem and they booked us in overnight which disrupted our tight schedule. We finally got the keys at 1pm the next day and unsurprisingly it was a rush.

 

To answer you question the unit is above the bed towards the back of the unit and 1 metre from the internal back of the MH.

 

I still cannot for the life of me understand Dometics claim that the DC kit is designed the give cold air when driving when it seemingly cannot benefit anyone.

 

As for your criticism of people driving to the med in the summer without a/c. We live there more or less we are fully aware of the need and have been for 15 years which is why it was our number one priority. We had a/c in UK cars years long before it became almost a standard item here.

 

Your advice is most welcome.

However I am not spending hours on this forum and mailing others for help just for fun and your criticism of us is unfounded, unhelpful and not what i want to read at this stage.

 

I will post spec of alternator as and when I have it.

[Passera]

The alternator is as someone suspected a Bosch 150 amp

[Guest JudgeMental]

Well there is your answer...the unit is simply fitted in the wrong place. For what you want (and I don't know your vans layout) but it would need to be fitted in lounge area, above your head just behind the cab seats.

 

again the dealer does not seem to have much of a clue. and has taken the easiest option of fitting in existing 40x40 roof vent above rear bed? do you have a Heki roof light over front lounge area? get dealer to remove a/c unit, reinstate roof vent, and refit as close to the front of van as possible behind Heki (if you have one)even if he has to make another 40x40 opening*-)

 

I bought our 12v/230v waeco because previous van with cab a/c was like an oven in the back (Fiat rubbish) so it was to keep the kids cool.....the new Ford cab a/c is so good that we don't need to use roof a/c on the move, so for us the 12v side was a waste of money. it does struggle on tick over but once revs pick up it works fine.

 

when yours is on 230v make sure 230v is actually getting to the system. I have had trouble with mains cable/ breaker's not turned on etc...

 

 

 

what model van? and how long is it

 

I am trying my best to get to the bottom of this.....

 

 

Call these people, they are very good and used to have alternator upgrades on web site which I cant find now..they should be able to tell you over the phone if alternator up to the job

 

http://www.conrad-anderson.co.uk/airconditioning-refrigeration/air-conditioning/dometic-b-2200.htm

 

from FAQ section:

 

"Will I need to upgrade the electrics on my fiat ducato based camper to fit aircon?

 

Not normally on a system of 1.5 to 2kw AC only. However larger units and dual voltage units will possibly require some form of upgrade to the system.

[Passera]

The van is a Lunar Premier H592

 

It has neither a Fiat or Ford but is a renault master without a/c.

 

We do have a Heki which is situated mid point pretty much over the kitchen area. There is room between that and the drivers seat but would require cutting into the roof.

 

I have the a/c running right now on 240v (how do i check 240v is getting thru to the system) Would i be correct in saying it must be 240v or it would drain the batteries.

 

The result is the same it is set on 16C and a humming starts at this point cold air emits. The humming stops and non cold air comes out. The period the humming is on does vary.

 

Will give ca a call