# Re-speccing new Vans power system



## gromett (May 9, 2005)

I am planning my new electrical systems etc for the new Van.

What I am looking at is as follows
1 x B2200 Dometic Air Conditioner (http://www.obrienscamping.co.uk/air_conditioners.htm)
4 x 220Ah batteries (http://www.unlimited-power.co.uk/deep_cycle_battery_carbon_fibre_elecsol.html)
4 x 200Watt Solar Panels (http://www.unlimited-power.co.uk/kyocera_solar_panels_pv_modules_uk.html)
1 x Victron Multiplus Inverter/Charger 3000Watt (http://www.yachtbits.com/victron_energy/victron_phoenix_multiplus_combo_charger_inverters_12v.php)
1 x 3.6Kw Honda Generator (http://www.power4motorhomes.co.uk/ev3610.htm)

I will mainly be using the AirCon when in France during the summer and need to operate it free of Shore Supply most of the time and want to minimise generator usage due to noise levels.

I am guessing that the Aircon will bring the habitation section of my motorhome down to a livable temperature within 10 minutes and will then be used intermittently to keep it down. I spend around 4 hours a day in the Motorhome when abroad so based on the 910Watts spec I would use 910 x 4 Watt/hours a day. As the solar panels will put in 800Watts/hour I am estimating around 6 hours total input is 4800 watt/hours in and the air con would use 3640 Watt/hours.

I know the solar panels won't give me 800Watts at peak but I am also not taking into account the sub prime period of the day. ie I may still get 100 watts out of it at 6pm but am not counting this.

The only other item that uses power is the Datastorm which uses 10amps off the 12Volt batteries. I only use this intermittently and switch it off when not in use.

What I am trying to achieve is 
a) Minimal use of the generator.
b) be totally self sufficient regarding power
c) Have enough power to do everything I want and if I overuse can power everything via generator and recharge batteries at same time.

I am sure I have missed some details.

Oh and by the way I may be selling my old Victron Kit as I need the 3Kw one for this setup.

Cheers
Karl


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## Scotjimland (May 23, 2005)

gromett said:


> I am sure I have missed some details.


The price tag ? :lol: :lol:

But seriously, this is a lot of expensive kit, best of luck. 
I presume you are installing yourself, have you calculated the extra weight?


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## DABurleigh (May 9, 2005)

Karl,

If your requirements are as stated (aircon away from shore supply most of the time and minimal noise), I really must advise you against compressor aircon. Your energy budget on average will be worse than you assume and you underestimate the thermal mass of a sun-soaked van.

Go indirect evaporative instead:
http://www.waeco.com/en/317.php?PHPSESSID=40002b98f09c0ff9636cb9d0d0b2ae26

Dave


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## teemyob (Nov 22, 2005)

*Aircon*

Hello Karl,

Are your talking about the France we all know?
Is your motorhome going to be Black?

Save your money forget the Aircon (Habicon).

Honestly why do you need or rather want it?

We have camped in day temperatures of +45C and never once ever thought "wish we had habicon".

I hope my advice helps.......

Trev


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## olley (May 1, 2005)

Hi Karl, we have camped in temperatures of 45C and thought "wish we had aircon"  got it now and wouldn't be without it.

Olley


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## gromett (May 9, 2005)

Teemyob, Sorry m8, done the 45C tempertures too many years now. On the coast its not an issue with low humidity and a fresh ocean breeze. In land it is stifling. I am doing aircon one way or another.

Daburleigh. Not enough info from your link. I understand Aircon and how it works. The waeco site doesn't give enough tech info for me to compare or even consider moving across. I am suspicious of anything that sells itself as better than what the rest of the market offers. As I read it it uses the evaporation of water? I would rather double the batteries etc than get something that uses less power and isn't as effective. Or even use genny once every couple of days. I am open to be pursuaded tho.

ScotJimLand: No Budget mate. I will spend whatever is necessary providing it is good value for money. No Kids, No Family etc etc.

weight is not an issue, I have 1100Kg of spare load weight. The price of the setup I have specified is around £9K I can go another £4K if necessary. More would have to be considered on a pro/con basis. Roof space will be pushed if I go beyond 4 x 200 Watt panels.

>Scratches head<


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## Rapide561 (Oct 1, 2005)

*Aircon*

Hello

Unable to offer any technical help, but all I know is, it is March and I wish I had aircon.

Slightly worried about the weight of the stuff though. What van have you ordered?

Russell


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## DABurleigh (May 9, 2005)

Karl,

Yes, the evaporative colling technique does use water. Perhaps this link gives you more, but I am not trying to convince you; it won't be my mistake. Buyer beware.
http://www.vecam.it/2005/gb/news/dettagli/coolbreeze.asp

If you want true aircon away from hookup, you need a genny going. That being the case, you either wildcamp away from others, or you choose a campsite where your neighbours are very separate.

In my case, I've gone true mains aircon on the roof, but it is sized such that it complements the dash aircon while driving, so the whole vehicle arrives cool, not just its driver and copilot.

Dave


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## Snelly (Aug 20, 2005)

Karl, this all sounds like one hell of a system just to keep you cool! Good luck with it, im all for going the extra mile gadget wise...


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## 88927 (May 10, 2005)

Hi Karl
Just a thought mate.......
All that weight up on the roof (A/C, Datastorm and Solar Panels), will it affect the handling of the vehicle or make it unstable? Maybe need to check this out and possibly have the suspension beefed up?
Good luck with the rest of the refit though, I cannot comment on the A/C question as we have proper A/C and use it when we need to. Regarding the use of your genny, we use ours if and when we need to and it is quite quiet, but with consideration for others. I am sure that the silence guys will not like to read this but I believe in live and let live so there it is.
If we were all considerate to others, in every respect, I figure that no-one should get bent out of shape (but I am sure they will :lol: :lol: )
Hope to see you soon matey, stay safe....

Keith


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## Snelly (Aug 20, 2005)

The other thing you could do Karl is sell your van and invest in an RV! All you need to do is your C1 or C, depending on weight.


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## gromett (May 9, 2005)

Thanks guys,
the weight isn't an issue.
Datastorm is 88KG, Aircon is 34Kg, Solar panels are 18.5KG x 4 (74KG) Total of 196KG.
The Batteries add 160Kg so even with all this kit on I am only at 356Kg.
Add a little for the wiring and ancillary equipment.....

Keith, its a tag axle so is more stable than normal euro models 

Russell, I have bought a Euromobil 770HS, I have Just over 1000Kg of spare capacity in it. 

Snelly, It has to power my Datastorm and 2 computers as well but I know the power requirements of these  I can't go for an RV for a couple of reasons. one is size for getting to my favorite places in France, Second is MPG. Euro vans are a lot better for me I think. Anyway already done 

I have read up on the coolbreeze and it becomes less effective as humidity increases. The places I will want to use it the most are when it is the most humid and intolerable. Secondly as I read it, it can only cool to the temperature outside the vehicle. So if it is 45C and very humid its efficiency will be greatly limited whereas a standard aircon unit will still work albeit with higher power requirements.

Cheers
Karl


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## DABurleigh (May 9, 2005)

"Secondly as I read it, it can only cool to the temperature outside the vehicle."

Nope. If that were all, opening windows and waiting would be more cost effective 

I am certainly not a fan of direct evaporative cooling. Indirect is worthy of consideration, however. I don't like humidity either. So, one's solution preference is simply down to a compromise between reduced humidity, energy budget and noise, plus whether it can be run while mobile or just static. These are personal choices and there is no right answer. If I had my time again, I would have difficulty choosing, but it would be between what I have, and the Coolbreeze.

But I still think the way you are going you will be using the genny for aircon FAR more than you calculate, and aircon will have to be on much longer than you estimate to pull the temperature down.

Dave


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## 103223 (Mar 2, 2007)

Regarding generator noise, last summer we stayed on the Calais aire beside a family in an old American C-class who had their generator running all day.
It was OK though, because playing The Doors and jamming along on their guitars masked the noise well.


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## gromett (May 9, 2005)

I hate generators hence my large battery bank idea.
I have one of these small aircon units you hang out the window. on my old van with 400Ah of battery and no solar panels I could go for about 9 hours without having to hook up. I only have aircon on to take the edge off the temperature as I do like it warm. This is usually for 20 minutes 1st thing in the morning, 1/2 an hour last thing at night to help sleep. And 1/2 hour here and there through the day probably 2-3 times while I do some work. So 2.5 hours at 910 watts is 2275 Watt hours. not quite the same as AH's but near enough for rough calcs.

Solar panels 800watts over 6 hours which I think is conservative (i Hope) give s 4800 watt hours. I still think I am in credit on this system.

Just hoping Frank (SallyTraffic) can give me some ideas?

Cheers
Karl


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## sallytrafic (Jan 17, 2006)

Hi Karl

You might have a surplus in some summer months I haven't crunched the numbers (too busy with campsite at mo) but 200W is nominal. It depends on orientatation yours will be flat on top I expect which will reduce output, and on sunhours (which is equivalent time per day that sun is producing 1kw/m2)

Have a work through the solar guide or the spread sheet to get a better idea. >solar calcs and guide< Please note however that I am not responsible for the solar max caculator which follows it.

I will say though in high summer having the number of Watts of nominal solar power equal to the number of Ah ain't too far out but you could double the output and still not charge the batteries in Winter

I'll get back to you when I'm free

Frank


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## sallytrafic (Jan 17, 2006)

Ok I have checked it out using your figures for aircon and some guesses for the other loads TV lights etc and using the autonomy of two days. [ie the time you rely on the battery system between getting enough sun or running a genny hooking up or driving] and the answer I get for southern UK is shown below. *Unfortunately I don't seem to be able to add an attachment at the moment I think there is an MHF problem*

This means that on average you will have a surplus only from May to July ie more energy coming in than going out..

Note that the spreadsheet as is assumes that the power to come back up to full charge has come from your solar panels when actually it will probably come from one of the sources mentioned above. Including that factor will improve things as you can guarantee that on the third day of no sun you can put all the power back in regardless.

Note also that the Watt hour replacement figure is constant in the table. So implying that you use as much Aircon lights and TV in the Summer as Winter. Clearly that is a nonsense and in the winter months you will use little or no aircon. Aircon (and fans) ie a load used more in the Summer than winter was not a factor originally thought of when this spreadsheet was conceived. What you could do is calculate your watt hour requirement for each month and override the simple figure in that column.

OK thats two pluses now for a big minus.

The autonomy is calculated by assuming you are willing to let your battery discharge to down to 10%. You may wish to be more conservative and only allow discharge down to 50% in that case, far from having a battery which is the right size (by my calcs you need 700 Ah) you would need about 1300 Ah. Or you can leave it at 880 Ahr and accept 30hrs autonomy instead.

Also note these calculations are based on long term sunhour data from the met office for the south of England, in Scotland or Spain the answer will be far different.

With more data and more knowledge about what you are actually trying to do (autonomy, depth of discharge etc) I could design your system for you but I reckon you might not be able to afford me as a consultant. 

Regards Frank


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