Run Vehicle Air Conditioning Without Idling

[Boxster1971]

I was recently looking at Volta Power Systems offering on their web pages. I notice they offer a 48V DC Air Conditioning (AirCon) System that they say works with any vehicle factory AirCon. Copy of their sales sheet attached.

See bottom of their web page...
https://voltapowersystems.com/energy-storage/

That peaked my interest as a way for a small B-van to have AirCon without adding a second AirCon system on the roof. There are a lot of DC AirCon compressors, with voltages from 12 to 420, on the market used mostly in either Electric Vehicles or for vehicles that need AirCon without idling, like the trucking industry. MasterFlux looks like that same compressor that Volta is using.
https://www.tecumseh.com/en/Corporate/Masterflux

Found one Australian company, RenCool, that sells an entire 24V DC system. Copy of their basic dual mode system diagram attached.
https://www.rencool.com.au/product/rdk7-24/

I’m wondering if this could be a viable option to get AirCon in a B-van when camping? Would it have enough capacity to cool down van? I have to look at the numbers of a typical van factory AirCon capacity.

I use my roof top 120VAC AirCon system so seldom I'd sure like to not have it in my next van. But would still occasionally need some AirCon capability.

Where you put the DC compressor, how you tie it into the vehicles refrigerant lines and how you control it are all unanswered questions. It also might be too complicated compared to a standalone DC AirCon System like ProAir offers. But it might save weight.

What do you all think?

Comments and discussion welcome.

- - Mike

[booster]

I have thought about it numerous times, although slightly in a different way than described.


My thought were always along the lines of using the complete van system, including the compressor, so no intrusion into most of the system at all except for driving the compressor. I think it could be an electric motor, belt system with another clutch or perhaps direct drive off the rear of the compressor.


There are issues, though, I think, and they may make the whole thing impractical.


You need to not only run the compressor, but you would need to run the AC cabin blower and also electric fans for the condenser. Both of those fans are not normally high efficiency and could easily make the whole energy use to high.


The van AC system is van computer controlled and has a whole bunch of safeties and sensors to prevent overpressures, underpressures, freeze ups, etc. I think you would need to interface with the van electronics to make it work reliably without chance of damage or inefficient running.


All the waste heat is going to blow against the firewall and under the van, so the van would gain some of the heat back from that.


I think focusing on very high efficiency, high voltage DC, air conditioners with the best possible condenser location for optimum cooling would probably work out much better as a very big condenser can be used and airflow to it controlled more precisely.

[Boxster1971]

Booster - I agree with your commnets. I had pretty much given up on the idea as it would be too hard to do. But after the revived discussion on the ProAir 12VDC AirCon - just thought I'd float the concept to the forum.

Last week I found this interesting concept video on YouTube. It's Green-Aire DC Driven Air Conditioning on a large truck, but it appears it never went anywhere.

https://youtu.be/NmKLWygbgH8

[israndy]

There have been Sprinter RV conversions in the past that used AC that didn't run off shore power. The most obvious one I can think of is the Airstream Westfalia, it has a big 12v roof AC and now that those are all more than a decade old they are failing and people are trying to replace them and finding it isn't very easy.

In the meantime, I got a new AC unit for my RV that was only $500, I was able to reuse the controller board from the original as it's the same manufacturer, even though the new AC unit is a different version (Penguin II) of the AC that came with my RV.

I think the better bit is these new high capacity energy storage units for RVs. The Pure 3 system that Winnebago is putting on the new Travato has 8700 watts of storage, enough to run the AC all night. If you need the AC on into the day the engine comes with a second alternator that charges the Pure 3 back up in under 2 hours. There is even a system that tracks the temps in the RV and turns on the engine to keep the AC running while you are away if you like.

-Randy

[Brad1998RD]

Myself I'd stick with the tried and true method until these things have been out in the real world for a number of years and parts are able to be had at an affordable cost.

[Jostalli]

ProAir is too power hungry. They don’t make a small unit.

We had an Autoclima UGO 12V in our first van. It was a little underpowered. We have also tested the following: Autoclima Fresco 3000, Cruise N Comfort 8000 btu, and the Kingtec K20D.

For split units the Cruise N Comfort is best. Best rooftop unit is the Kingtec.

We have a Kingtec going in one of our next Sprinter 144 builds.

Volta is an amazing system. We are currently in discussions to carry their product. They are very protective over their technology.

[wincrasher]

Coachmen is offering a 12v air conditioner unit in their new Gallerias. I'm not familiar on the details, but reports are it works well (something like 30% lower power consumption - Lithionics they only use a 600 AH battery), and is much quieter that standard rooftop air conditioners, which is also a big factor.

[Jostalli]

Originally Posted by wincrasher

Coachmen is offering a 12v air conditioner unit in their new Gallerias. I'm not familiar on the details, but reports are it works well (something like 30% lower power consumption - Lithionics they only use a 600 AH battery), and is much quieter that standard rooftop air conditioners, which is also a big factor.

Yes they use ProAir. It’s a 20k btu unit, which is larger than it needs to be. Draws almost 100 amps.

[Tim Baker]

Where did you buy the Kingtec K20D?

[Jostalli]

Originally Posted by Tim Baker

Where did you buy the Kingtec K20D?

We are a Kingtec dealer

[Boxster1971]

Originally Posted by Jostalli

Yes they use ProAir. It’s a 20k btu unit, which is larger than it needs to be. Draws almost 100 amps.

Thanks for the info. The numbers on the Kingtec K20D look a lot better than the ProAir. Their brochure says at 12V it is 45A at 35C (95F) for a more reasonable capacity of 11,000 - 13,000BTU.

[jon]

Originally Posted by Boxster1971

Thanks for the info. The numbers on the Kingtec K20D look a lot better than the ProAir. Their brochure says at 12V it is 45A at 35C (95F) for a more reasonable capacity of 11,000 - 13,000BTU.

I wanted to install a Kingtec K20D but could not find any real life experiences online. I have my doubts about real 12K BTU with 12V 45A. That's only 540 watts. True 12K BTU units seem to use well over 1000 watts.
I had a 12V split system that was supposedly 8K BTU but if felt closer to a 5KBTU unit and it drew over 40 amps.
I'm not saying it's not true. I haven't been able to find any reviews or any info.
So I bought a Colman Mach 8 cub.

[mlts22]

I wonder about Danhard as an option... but I've not heard much about them, other than from Sportsmobile.

[Boxster1971]

Originally Posted by jon

I wanted to install a Kingtec K20D but could not find any real life experiences online. I have my doubts about real 12K BTU with 12V 45A. That's only 540 watts. True 12K BTU units seem to use well over 1000 watts.
I had a 12V split system that was supposedly 8K BTU but if felt closer to a 5KBTU unit and it drew over 40 amps.
I'm not saying it's not true. I haven't been able to find any reviews or any info.
So I bought a Colman Mach 8 cub.

You might be right. After I posted that comment last night I did a bit more looking. The reviews of Kingtec on Amazon are mixed. It is a total Chinese product so any claims need to be questioned until proven accurate.

[ClassB4Me]

https://www.youtube.com/watch?v=4odiifwG5DE

[Snowy]

Originally Posted by Jostalli

Yes they use ProAir. It’s a 20k btu unit, which is larger than it needs to be. Draws almost 100 amps.

Coachman stopped putting the ProAir 12v A/Cs in the Beyond because they were just too unreliable. They started putting in the Premier Turbo 12v A/Cs about a year ago, and there have been some recalls and other problems with the new units, but it is too early to tell if they are as bad as the ProAirs. I think the consensus on the Beyond FB page is that the best bet right now is probably to go with the 120v Colman NDQs because they seem to be very reliable.

[Snowy]

Originally Posted by wincrasher

Coachmen is offering a 12v air conditioner unit in their new Gallerias. I'm not familiar on the details, but reports are it works well (something like 30% lower power consumption - Lithionics they only use a 600 AH battery), and is much quieter that standard rooftop air conditioners, which is also a big factor.

The Premier 12v A/C Coachman is installing has the good specs you quote. I saw a youtube video where Camping Coastie showed good power draw and noise characteristics. But now some on the Beyond FB page say that while it is quiet on the inside, it is too loud on the outside. Note i said some - there are people with the Premier 12v A/C that have no noise, water drip, or failing to cool problems.

[Snowy]

Originally Posted by Jostalli

Volta is an amazing system. We are currently in discussions to carry their product. They are very protective over their technology.

I follow the Travato FB page. The consensus there seems to be that the volta system is pretty cool, and the people who have it love it, but:
* The parasitic draw of the inverter is quite large.
* It is a black box without any easy way to do/get repairs. Volta has been pretty responsive but this remains a concern.
* There have been many reports of cooling system hoses getting slashed by the belt for the 48v alternator. This problem seems less common than in the early days of the volta system.
*While the system charges in an hour or two while driving at highway speeds, it takes many hours to charge while idling the engine. They use a high-idle mode with the promaster to speed up the charging but it is still slow and high-idle is pretty loud.

One good thing about the Volta system is that it uses LiNiCoMn batteries that are much more cold tolerant than the standard LiFePO4 batteries you see elsewhere.

[Snowy]

Originally Posted by israndy

The Pure 3 system that Winnebago is putting on the new Travato has 8700 watts of storage, enough to run the AC all night.

Actually, the Travato now offers a fourth battery Module now, and so you can get 12,800 usable watt-hours! And by usable, they mean the actual part of the battery you can use, not the total capacity of the battery. This helps with the inefficiency of the inverter and DC-DC converter, but increases the already long charge times at idle.