12v Roof mounted air-conditioner

SimonM

SimonM

Full Member
Posts
1,938
Likes
5,364
With the unusually hot weather at the moment I was pondering the benefits of proper air-conditioning, not the standalone devices that push air around, or need to be plumbed out of a window or door. I am not interested in one of those at all.

Obviously all I’ve previously been aware of are usual ‘Dometic’ type of units frequently seen on continental MHs, that are mains powered, therefore requiring to be hooked up.

I’ve seen a few adverts for a 12v version and wondered if anyone has one yet, or any knowledge of how worthy they are. I will bear in mind a need for a high quality solar bank and Lithium battery setup, I’ve 520w solar and will likely be expanding my Lithium as well. I already have a suitable hole in the roof for it to mount.
 
I've no experience of a 12v one, but our roof-mounted Dometic runs fine off the Inverter - pulls around 1200W when on max cooling. It'll sometimes trip our 1600 Multiplus II inverter-charger due to the in-rush current when it starts up, so I generally start the blowers first, then turn it onto cooling.
 
That’s interesting to know, I just assumed a 240v one was a non-starter and didn’t consider one. My inbuilt inverter is 1800w so that’s a possible. Although 1200w = 100 amps and I assume you’ve a large Lithium bank?
 
Our concorde had the soft start version in the bedroom , a dometic i believe! This was easier on the inverter/ battery bank we found setting it to a couple of degrees below outside temp kept the bedroom sleepable and as the outside cooled down at night the air con didnt kick in too much
 
IMG_5700.png
 
I was checking out a Truma Adventa Comfort Roof Air Con unit on Sunday. Hitting around the 1000W mark, which is around the 80A or so, which is fine for say 1500W inverters or more.

1782229058770.png


But .... the definition of "soft start" may vary?

@andyjanet,
I see that your soft-start comment is an AI Response? :)
I will take your AI Response and raise you another AI Response :D .....

This is what Co-Pilot says about the Truma:

1782229438365.png

So according to this, even with that stop-start in the Truma, there is still a very small surge, and a very significant one.

In my case, the Victron Inverters are very good ar dealing with surges.
1782229542662.png

But this is not always the case with many other brands, and there are some that are absolutely useless at surges and will just blow a fuse :(


Just to complete the AI response ...
1782229750577.png



Back to the question on 12V ACs vs Mains ACs, you are still talking high current and so you will need nice fat cables, and if the Unit is on the roof, those cables will need to be routed up the wall and across. And then because they are in the wall and constricted, they will get hot unless you mitigate that with even bigger fat cables. And from I have read generally over the years about the 12V units, they are not actually very good :(
 
Thanks David! The AI responce was first to pop up, we had the concorde with two roofmounted air con units main seating kitchen area and shower room / bedroom depending on the remote vents , both were dometic that worked off the same remote control, we had 750 amps of AGM batteries that weighed 1/2aton and a battery master system that you didnt turn on it came on automatically with demand. I will say the soft start was alot more forgiving on the batterys than the main living area type
 
I saw a vid posted on Youtube earlier that had click bait heading of 12V aircon, can you run from 12v battery, 300W

Its was a new posting but I didn't pay attention who it was and didn't watch it. I will have a look later and see if I can find it, id so I will link it here.

EDIT: I saw the vid shown on YouTube on the TV, just been searching on laptop and can't find it. Will see if it still shows in my lists on the TV when I go back
 
Last edited:
andyjanet said:
Thanks David! The AI responce was first to pop up, we had the concorde with two roofmounted air con units main seating kitchen area and shower room / bedroom depending on the remote vents , both were dometic that worked off the same remote control, we had 750 amps of AGM batteries that weighed 1/2aton and a battery master system that you didnt turn on it came on automatically with demand. I will say the soft start was alot more forgiving on the batterys than the main living area type
Click to expand...
it is not something I have checked for myself. I have on fridges and the surges are so short in duration sometimes you can capyure the spik, sometimes you can't. You can tell it happens as depending on the inverter, it may just fail to start, or give a shake and an overload for the 3 seconds or so.

The inside of the van was 37C at 5:30 this evening. Batteries are at 100% so I have turned on the AC and will see some time this evening (not sure when) what it goes down to and how much power it took to do so :)
 
My air-conditioning is a Dometic Fresh Light 2200 and runs fine on a Multiplus II 3000 with a 460ah battery.
I did check the BMS and was surprised how long the battery would last, sorry can't remember how long.

My knowledge of all this stuff is zero and am quite happy with the explanation it runs on witchcraft.

So a 240v option is very feasible.
 
I mentioned I was going to check the info this evening as it was hot ...
Here is a little graph of the Power usage of the Air Con unit for 2.25 Hrs.


1782243101461.png


So drawing 900 Watts off the inverter, pulling around 70-75A (Solar was providing about 5A average at this point).
To take the temperature from 36 Celcius at 17:30 down to 27 Celcius at 19:45 took 25% out of the batteries, which equates to 167 AmpHours.

Might be of interest to anyone contemplating Aircon and if they have enough battery to use when off-grid. One of the key things which it will be possible to do with this setup is run when driving as the B2Bs will push out enough power to run the A/C at the 900W shown above, which was part of the criteria.
 
I recall this guy trying out a 12V air con unit ... Brian from "RV with Tito". There are quite a few channels and posts on this subject on YouTube, but this particular guy I have a lot of time for as he does things properly and doesn't bullshit.

Now I don't know if I am remembering right, but I have a recollection that he was not that happy in hindsight? maybe check out any later posts from him? (like I said, straight talker so if it didn't work as planned, he'll tell you).
 
To be honest I fully expected those of you with 240v units saying not to bother trying using it on 12v with inverter. So I will further investigate a big increase in Lithium, part of me wants to go for 2 x 460ah Fogstar units, but I’ll need to figure out what my Merc alternator will kick out. Then go for a 240v unit and use it sparingly
Thanks for the useful replies 👍
 
Nabsim said:
I saw a vid posted on Youtube earlier that had click bait heading of 12V aircon, can you run from 12v battery, 300W

Its was a new posting but I didn't pay attention who it was and didn't watch it. I will have a look later and see if I can find it, id so I will link it here.

EDIT: I saw the vid shown on YouTube on the TV, just been searching on laptop and can't find it. Will see if it still shows in my lists on the TV when I go back
Click to expand...
Bus grease monkey channel had one not long ago, he rated highly, may have been sponsored
 
We are currently away and arrived in Calais yesterday afternoon. On setting up here I plugged in 2x240v oscillating fans along with all the vents wide open. It worked very well and my Lithium battery was showing at 70% now at 09.51.
 
SimonM said:
I’m increasingly less reliant on any advertising as so much is fake these days, and that’s why I’d rather hear real world reviews from those that actually know.
Click to expand...
He's a fairly straight no BS sort of chap, so they may be good, poss 24v, I'll see if I can find it.
 
Additional info from the WhatsApp AI.

Can we get this in the UK? https://countrymodpro.com/products/...vs-trucks-vans-campers?variant=50549355151669
Today




Yep, you can get the CountryMod Pro 12V 10,000 BTU rooftop AC in the UK, but there are a couple of hoops.

Buying options for the UK​

1. CountryModPro website direct
The official listing says "U.S. Warehouse Shipping" and "No import duties or hidden fees". That usually means it ships from the US. There's no explicit "ships to UK" on the product page, but UK van builders have tested it, so people are getting it imported. Expect shipping costs + UK VAT + potential customs handling when it lands.

2. Amazon
It's listed on Amazon as "Countrymod 12V DC RV Air Conditioner 10000 BTU". Amazon US doesn't always ship heavy items like this to the UK. Check the Amazon UK site or see if a UK seller has stock. Sometimes 3rd-party sellers on Amazon will ship internationally.

3. Already in the UK
There's at least one UK van that tested it: "First UK Van EVER to Test CountryMod Pro Rooftop AC". So units have made it over. UK RV techs and vanlifers are reviewing it too.

Things to know before ordering​

  1. Power setup: It's 12V/24V DC, draws 40-60A. UK RV techs recommend a 400Ah battery bank to run it 4-6 hours. You'll need proper cabling - it was designed for van builds so RV owners often have to upgrade gauge.
  2. Import costs: If buying from the US, budget for ∼20% VAT on product+shipping, plus courier handling fees. A unit like this at $800-900 USD could land around £850-£950 total.
  3. Roof opening: Needs a standard 14" x 14" roof vent opening. Same as most UK/EU caravans.

UK community feedback​

UK/EU vanlifers are using it because it's quieter than typical rooftop units and runs off solar/battery without an inverter. Noise is 45-60dB, depending on mode.

Quickest way to check:

  1. Add it to the cart on countrymodpro.com and put in a BD6 postcode at checkout to see if UK shipping shows up
  2. Message Countrymodpro directly - they reply to UK buyers on Facebook
  3. Search "CountryMod 12V AC" on Amazon.co.uk
 

Further info:-​

​

​

UK-market 12V rooftop ACs comparable to CountryMod Pro​

1. Dometic CoolAir RTX 2000 12V - Main UK option
Cooling: 6,824 BTU / 2000W
Voltage: 12V DC, draws approx 19A in Eco Mode
Type: Inverter compressor, rooftop mount
Noise: Low/quiet inverter compressor
Install: Fits standard rooftop, universal kit available
Weight: Approx 32kg
UK price: £1,800-£2,200 fitted. Unit only around £1,500
Pros: UK/EU warranty, dealers everywhere, proven in vans. Uses way less power than CountryMod - 19A vs 40-60A
Cons: Lower BTU than CountryMod’s 10,000, costs more upfront

2. Viesa Holiday IIIS 12V - Evaporative cooling
Cooling: Not BTU rated - uses water evaporation. Drops temp by approx 5-10°C depending on humidity
Power draw: Tiny - 0.5 to 5.8A
Water use: 0.5-1.5 litres/hour
Weight: 19kg
UK price: £1,200-£1,500. Needs specialist install
Pros: Runs for days off solar/battery, super quiet, no compressor
Cons: Not true air-con. Works poorly in UK humidity. Not great if you want proper cooling like CountryMod

3. eBay UK generic 12V units
Example: 12V Rooftop 12,000 BTU for £439
Example: 13,500 BTU heat & cool for £798
Specs: 60-80A draw, 26kg, similar to CountryMod
Pros: Cheap, UK delivery, no import VAT
Cons: Unknown reliability, minimal UK warranty, often 1yr only

4. Dometic ACC3100
Not actually AC - it’s a ventilation unit with heat recovery. Only 15.6W power. Won’t cool like CountryMod.

Key differences vs CountryMod Pro 10,000 BTU:

CountryMod Pro:
Cooling 10,000 BTU, Power 40-60A, UK warranty No, UK price £990-£1,275 landed, Install DIY 14"x14"

Dometic RTX 2000:
Cooling 6,824 BTU, Power ∼19A, UK warranty Yes, UK price £1,500-£2,200, Install DIY/pro install

Viesa Holiday IIIS:
Cooling Evaporative ∼5-10°C drop, Power 0.5-5.8A, UK warranty Yes, UK price £1,200-£1,500, Install Specialist only

eBay generics:
Cooling 10,000-13,500 BTU, Power 60-80A, UK warranty 1yr if lucky, UK price £400-£800, Install DIY

What UK vanlifers actually buy:

  1. Dometic RTX 2000 if they want reliability + UK support and can live with less cooling power. Most pro van builds use this.
  2. Chinese eBay units if they want CountryMod specs without import hassle. Risky but cheap.
  3. Viesa only if they’re in Spain/Portugal. Too humid for proper cooling in Bradford.
Dometic’s 19A draw means you can run it 3x longer than CountryMod on the same battery bank. The 6,824 BTU is enough for a SWB/MWB van in UK temps.

 
You must log in or register to reply here.
Back
Top