12v DC Air Conditioning Conversion Progress

[adamis]

Well, I'm knee deep into my Spring camper project. I posted about this earlier about all of the work I plan on doing but this update is specifically to the AC conversion. As a recap for those that didn't see my initial post, I am removing the roof AC unit and replacing with a under the dinette 12v DC unit. This is going in place of the furnace (which is being replaced with a Wave 3 Catalytic heater and is sufficient for my climate).

The AC unit I purchased off of Aliexpress for around $550 plus $250 in shipping. The price seems to fluctuate quite a bit by the way so if your interested in this project, keep checking those prices often. One note... This unit is actually a 24v DC unit but they include a 24v to 12v converter if you order it that way.

https://www.aliexpress.us/item/3256804887330541.html?spm=a2g0o.order_list.order_list_main.5.7eff1802...

So far the install has been fairly reasonable. The most difficult part is needing to change how the outside air is routed. This unit has the outside air vents on the bottom of it (for install in a van conversion where it would pull from air through the floor. I didn't want to cut any fiberglass to vent the air downwards so I'm rerouting the air to go out the side to make use of the existing hatch for the old furnace. The biggest part of my time is spent puzzling through how I'm going to fit the various pieces and what type of ducting I'm going to use.

I am recording all of this and will eventually have a video on YouTube to show how I did it for anyone else contemplating the same project.

For anyone wondering why bother doing this? Many reasons I suppose. First, I couldn't stand how tall the existing roof top AC looks on the camper. It stands out like a sore thumb. It's also susceptible to low hanging branches. It is a lot of mass high up on the camper impacting ride handling. It is inefficient and loud. The best part is that this new unit I will be able to run on battery and solar for most of my needs thus making it way more useful.

[valhalla360]

How big is your battery bank and solar array?

[adamis]

Currently I have 200w of solar and 100AH LiFePo4. I have plans to expand to 400w of solar but will see if it's possible to add even more once the AC unit is removed. for battery, I don't really plan on changing out my battery in the near future but I may see what the largest capacity LiFePo4 I can get either in the battery compartment or in the opposing Dinette seat (should be able to set quite a bit in there I think).

[valhalla360]

So how are you planning to power it?

50amp is 600w. Even at noon with no losses, you are pulling 200w off the battery bank. 

100amp-hr is 1200w-hr. Most of the day,  solar will put out a fraction of the rating.  In ideal condition you might get 3hr if you start with a full battery bank. 

[adamis]

Well, there are a couple of factors at play here. Right now I have 200w of power but I'll be adding another 200w and maybe 500w to 600w depending on what the roof looks like when I remove the AC unit. Expanding the battery bank to 200AH or even 400AH isn't out of the question either.

Another factor to consider is the duty cycle of the AC unit. It isn't always running the compressor when the AC is running. Once the camper is cooled down it may only run 50% or less of the time. That differential is what will extend the useful run time with a small battery and solar capacity.

When at the RV park or campground with hookups, we are going to install a120v AC to 12v DC 100amp converter that will power everything. I am also considering a Honda 1000 for those times when we need more power and can't get hookups or the AC / Battery aren't enough.

We live on the West Coast and most of the camping we do is in mostly moderate temperatures. Most of the times we need the AC is if we are stopping for lunch while we drive and that is usually about 30 minutes or so. We haven't traveled parts of the country where full time AC is required and most likely if we do travel to those parts, we will be traveling in something else.

[Camper_Jeff___K]

Interesting,  I have seen 12 volt DC units but they cost 2500 to 3000. I know a guy who installed one on his van a while back and he loves it. I don't recall the specific details but it does the job fast, doesn't seem to rough on his solar and lifepo batteries. I'll be interested to see the video when you post it.

[adamis]

Thanks. I'm plugging away at the project little by little as I have time. Goal is to have it all together before end of June so it's ready for Summer trips.

[StirCrazy]

coming along, was there any info on how it works in the box, ie is it refrigerant based or a different type of cooling, I can't find any info on it at all aside from what the seller says and all  they give you is frequency conversion cooling, what ever that is as I cant find anything with thoes words eaither except how to cool frequency converter hardware haha

[bigfootford]

Wow another innovative project!  Quite interesting.

[adamis]

Thanks Jim!

[adamis]

A few more pictures to share. I did end up removing the divider in the seat that separated the small compartment from the larger compartment. In these pictures I still have the piece of wood where the divider went but I eventually removed it because it was difficult to work around and served no purpose. Initially I was thinking of moving my battery to the small compartment but as of now, I'm leaning towards running the cable provided to where the existing battery is. The AC unit itself is 24v but they provide a 12v to 24v DC converter. The 24v wiring they provide is really quite long and will snake easily through the camper to get to the back where the battery is. The only real difficulty will be in getting the wire around some of the tighter compartments with limited access. It will be a bear to get it done but I don't foresee any show stopping issues. As part of this build I am also removing my oven / stove and replacing it with just a two burner stove. When I do that it will likely free up quite a bit of space to snake the wires around.

[adamis]

No, this is not a swamp cooler, it is an actual AC unit. Early testing I did yesterday with an inside camper temp of 88 degrees it was blowing cold air around 57 degrees and that was after running for just a few minutes. I'm in the middle of finishing up wiring details and such but I am continuing to record my process so others can watch the full build experience and gather from it what they may.

[StirCrazy]

interesting, they are pretty vage on ali express on any detais on how it works, but at full power 70amps (12V DC) thats not to bad, I was looking at a roof top unit made by the same company that uses freon and is a 12V system, but its only 2200 btu of cooling, and uses 60amps at 12V on max power.   

[adamis]

On my unit, internally it actually runs on 24v. If you purchase the 12v unit, they provide a 12v to 24v converter. This actually is pretty nice because I was able to put the converter really close to my battery compartment and I'll snake the 24v lines through the camper.

I measured about 50 amp draw on high on the 12v side. I'm working on wiring now as I am going to make the face mounted control panel remote so I can move it somewhere visible. Once I have that done I'll be doing more testing and get more testing information.

[StirCrazy]

ya I saw that about the 24v, I would almost be tempted to do a 24V or 48V battery setup if I had that.