I'm "split" over window air conditioners ;)

[AntiGroundhogDay]

Retiring at the end of 2019 to vanlife and getting down to (van planning) business.  Vehicle of choice is an insulated 159in RAM Promaster 2500 High Roof and I will be rocking ~900-1000w of solar on top, 4-600Ah of lithium batteries, and genuine air conditioning.  Oh the price of comfort.  I will be drawing a sealed off, insulated curtain (as sealed off as I can get it with velcro or snaps, open to other ideas) behind the front seats to minimize solar gain and drawing another curtain to seal off the bedroom from the kitchen area.  In order to minimize electrical loads, I will be cooling the raised bed at the back of the van only.  I found these calculations helpful, if anyone thinks there is a better way to calculate, please let me know:


Here are some examples of folks running A/C off solar/batteries:

 


Now on to the A/C.... being an East Coast guy, I assume I'll spend some time in urban/suburban areas as well as out West.  Stealth is very important to me (as much as you can be with a bunch of solar up top.  Might use the H2 Vantech racks to conceal it a bit: https://vantech.us/RAM-ProMaster_c156.htm) so hanging a Window A/C unit out the back window, or even baffling it internally w/ a large grate on the outside didn't appeal to me.  But the inefficiency of a portable unit, nor the cost and trouble of concealing a ductless mini split did not work for me either.  Enter the DIY mini split from a cheap window unit:



I would follow this guy's general lead in installing this in his Sprint, but the evaporator/compressor/fan/controls portion of the unit would be mounted like this: https://www.midwayrv.com/console/photos/inventory/large/0421e349074d0b5.jpg

The other fan and condenser would be installed here on the promaster: 
https://1.bp.blogspot.com/-reh51Kai...gJDqf5Slga-buTwCKgB/s1600/20150927_184006.jpg
https://2.bp.blogspot.com/-9hoT0-lB7gM/VkGHXvyZl_I/AAAAAAAAKt8/34lih-QGZio9e3dQ0Jgqe3j_UkoJg-0twCKgB/s640/20150927_184020.jpg
 (re: the pictures, this guy wanted to install an AGM battery in this spot under his Promaster, but I see no reason why the fan and condenser can go here, towards the rear of the van, but forward of the rear axle.)

Benefits would be:
- Reduced sound for stealth.  All you will hear is the sound of the fan blowing over the condenser, and that will be concealed way under the van.  The sounds of the compressor kicking on/off will be contained inside the van.

- Reduced visibility for stealth.  You will not see any evidence of an A/C mounted or running unless you crawled under the van.  But I will admit, condensation drain line will drip water on the ground unless I terminate it in a container inside the van (at the slight loss of efficiency, not dripping it over the condenser) and empty it every once in awhile.

- Cost (maybe?).  Window A/C units are cheap and readily available, but the video shows some soldering and then charging the system.  I can solder, but I do not have the tools or knowledge to charge and test the system.  What would that cost in labor if I were needing to replace the A/C unit after a few years?  Licensed HVAC guys make good $.  Would need to extend the copper refrigerant lines from the back of the van up near the roof, all the way down to underneath the van.

- More efficient than a portable unit and thus less electrical load.

So.... why isn't this more popular?  Seems like a slam dunk to me, I'm probably missing something here.  Maybe folks like to go off road a bit and worry about the condenser being damaged?  Maybe it would be tucked up far enough not to worry?  Maybe install some chicken wire over the fins to protect from the occasional rocking kicking up?  Has anyone tried?  Thanks!

 

[frater secessus]

It's above my skill level, but looks like it would work.  

I was considering an internal (ducted, forced air) window unit for cooling until I was able to get a work transfer to the high desert.  They are an amazing value for price and BTU.

 

[Rabbit]

I'm no expert, but when researching a similar decision I learned that many consider mini-splits to be extra-susceptible to vibration and thus to have short lives in vehicular applications. It's been long enough ago that I can't provide links and in the end this wasn't a deciding factor in my choosing a window unit, but... I definitely read that in several places.

Are window units engineered to be any less susceptible? I don't know. All I have is a suspicion that they indeed are, due mostly to their common nickname of "window-shakers". Certainly mine's held up well to repeated massive pothole jars so far.

 

[AntiGroundhogDay]

I'm no expert, but when researching a similar decision I learned that many consider mini-splits to be extra-susceptible to vibration and thus to have short lives in vehicular applications. It's been long enough ago that I can't provide links and in the end this wasn't a deciding factor in my choosing a window unit, but... I definitely read that in several places.

Are window units engineered to be any less susceptible? I don't know. All I have is a suspicion that they indeed are, due mostly to their common nickname of "window-shakers". Certainly mine's held up well to repeated massive pothole jars so far.

Yeah due to mini split pricing I haven't researched them much, but certainly have been in awe of their SEER/EER efficiency ratings.  I'm not really sure how they obtain the ratings, or why you found them to be more fragile, but in my head this DIY mini-split will be just as reliable as other vandwellers have found window a/c units so long as the soldering of the extended copper refrigerant lines are quality.  The only worrisome part is the susceptibility of the condenser rocks and road debris as well as bottoming out.  But seeing as the Promaster has 7in of ground clearance to the fixed rear axle, then the spare tire under there lends another 8.5in to the underside of the frame, I think I can protect it pretty well, even install some chicken wire over the fins to protect them a bit.

Does anyone have ballpark estimate for the cost of a technician to solder a few lines and recharge the system if I do all the mounting and put the extended copper line extensions in place ahead of time?  Heck, the benefit of this being installed in a van, I can even drive to the technician's place of work!

 

[DannyB1954]

In my build I put in a bulkhead across the rear of the vehicle. I did this for several reasons. One being to create a secure area for storing expensive items when I was away from the van, (most vehicles are real easy to get into). The other was so I could have a vented space for propane bottles and a small generator. Into this bulkhead I installed a 5,000 BTU air conditioner. The condensor hot air is vented out through roof vents in the garage area. This also acts as a vent fan for the garage.
The air conditioner is powered with 960 watts of solar panels on the roof and an inverter. On cloudy days the A/C can also run off of a 900 Watt propane generator. Solar panels never put out their rated capacity. If there is a cloud that gets between the sun and my van, the solar panels will not supply enough power for the A/C. Intermittent clouds are OK as when the sun does shine it can run the A/C and recharge the batteries.
I only wanted enough battery to run my 12 volt compressor refrigerator and some lights over night, (weight becomes an issue with lead acid batteries). I like this setup because with the number of panels that I have can quickly charges up the batteries in the morning even with little sun, (960 watts charging 200 watts of batteries).
Here is my build video
It shows the system with the amp readings in both full sun and under a cloud running the air conditioner. My channel is not monitized so the videos I have are just there as a public service. If you have questions I will try to answer.
BTW, there is very little way to stealth with an A/C unit running. You will need either lots of solar panels or a generator. The A/C unit itself makes noise. For cooling at night, it would have to be under generator.

 

[jimindenver]

I am one of those videos. When I decided to do it the general consensus was that it could not be done, had not been done and thast there was no reason to discuss it. That was years ago and now it is not that uncommon. With my full 1185 watt solar system I have been able to run both of my 5000 BTU window shakers and still hold the voltage of the bank.

My question is that while the efficiency of the mini split is better, you will be cooling a very small area that the window shaker I use can do easily while only pulling 410 watts. The mini split will pull more than the window shaker will while the expense and effort is much higher.

 

[debit.servus]

There is a PORTABLE mini-split air conditioner. If you need to know why this is a big deal, split A/C units are fundamentally the most efficient form of A/C, and until now have not been available in a portable form. Window A/Cs are hard to stealthify, Mini-Splits are costly and need permanent installation, and Rooftop RV A/Cs are overkill for a van.

http://www.forestair.ca/en/serie-mini-anglais

This is a portable mini-split A/C that’s 8,000 BTUs & under a grand. I presume the price on the page is in CAD ($900 +? tax), which at today’s exchange rate it’s about $700 US. It is possible to assemble yourself and the refrigerant hoses are a good length, flexible and look to be quick connects. All you need is a 3-4 inch hole for the hose run. Unfortunately it’s only sold in Canada for now, but that doesn’t stop us Americans from owning it. You’ll need to ship it to a friend or mailing address in Canada, then find a way to receive it.

https://vanlivingforum.com/showthread.php?tid=30489

 

[AntiGroundhogDay]

In my build I put in a bulkhead across the rear of the vehicle. I did this for several reasons. One being to create a secure area for storing expensive items when I was away from the van, (most vehicles are real easy to get into). The other was so I could have a vented space for propane bottles and a small generator. Into this bulkhead I installed a 5,000 BTU air conditioner. The condensor hot air is vented out through roof vents in the garage area. This also acts as a vent fan for the garage.
The air conditioner is powered with 960 watts of solar panels on the roof and an inverter. On cloudy days the A/C can also run off of a 900 Watt propane generator. Solar panels never put out their rated capacity. If there is a cloud that gets between the sun and my van, the solar panels will not supply enough power for the A/C. Intermittent clouds are OK as when the sun does shine it can run the A/C and recharge the batteries.
I only wanted enough battery to run my 12 volt compressor refrigerator and some lights over night, (weight becomes an issue with lead acid batteries).  I like this setup because with the number of panels that I have can quickly charges up the batteries in the morning even with little sun, (960 watts charging 200 watts of batteries).
Here is my build video  
It shows the system with the amp readings in both full sun and under a cloud running the air conditioner.  My channel is not monitized so the videos I have are just there as a public service. If you have questions I will try to answer.
BTW, there is very little way to stealth with an A/C unit running. You will need either lots of solar panels or a generator. The A/C unit itself makes noise. For cooling at night, it would have to be under generator.

I definitely saw your video at one point, apologies if I missed linking it above.  I thought about your design, but a few things weren't optimal for me:

- Venting the condenser through the roof makes me itch.  The more intrusions w/ with the roof the more chance for leaks, but I see why you did it.
- I understand why you have the bulkhead separating the living space, but perhaps I can have my cake and eat it too with my design in that the GF and I will still get those Instagram p) pictures being able to see out the back of the van and with two people I'm want to preserve as much living space as possible w/ a dog as well.
- The side vents to your window A/C unit... they are there to draw air in the sides and blow it across the condenser as well as keep the compressor cooled, right?  If so (I'm by no means an expert), then do you worry about not having enough airflow behind your bulkhead when the backdoors are closed and the area is heating up in the hot sun?
- The "secure garage" you have with the bulkhead, are the rear doors more secure than the others or do u have a lockbox in that area?

As for "there is very little way to stealth with an A/C unit running," I realize a roof full of solar isn't exactly stealth but in big cities, there are tons of vans with racks, we'll see.  I'll practice the whole "move around a lot and don't in the place you want to sleep until the absolutely last minute and get up early and go."  By splitting the window A/C unit into a DIY mini split of sorts, the noisy compressor will be inside the insulated van being muffled and the only exterior noise will be the fan blowing over the condenser well under the van.  Some noise, but hopefully not much.

Nice to hear it is running well during the day (when we most need it!).  I hope to attain the same and have a bit of battery for the first few hours of night when it still may be hot.  And of course when the sun goes down the compressor cycles on less.  We'll see.

 

[AntiGroundhogDay]

I am one of those videos. When I decided to do it the general consensus was that it could not be done, had not been done and thast there was no reason to discuss it. That was years ago and now it is not that uncommon. With my full 1185 watt solar system I have been able to run both of my 5000 BTU window shakers and still hold the voltage of the bank.

My question is that while the efficiency of the mini split is better, you will be cooling a very small area that the window shaker I use can do easily while only pulling 410 watts. The mini split will pull more than the window shaker will while the expense and effort is much higher.

That is my goal as well, to have enough solar to run the window unit (which I will "split" myself) during the day and recharge the lithium battery bank quick enough in the morning.  Hopefully the battery bank will be big enough to cool a bit into the first few hours of the night as well as the A/C unit cycles on less and less.

To clarify, if you want the video of the guy "splitting" the window A/C unit and installing it into his Sprinter... this is not a commercial mini split.  It's just a 5k BTU, cheapo, window unit that the owner has pulled apart and install the condenser under the van with a ice machine fan under his van, then extended the refrigerant lines up through the van to the rest of the unit (compressor and evaporator).  The benefits are cheap hardware, compact install, minimizing noise outside the van, no visual clues outside the van.

 

[AntiGroundhogDay]

There is a PORTABLE mini-split air conditioner. If you need to know why this is a big deal, split A/C units are fundamentally the most efficient form of A/C, and until now have not been available in a portable form. Window A/Cs are hard to stealthify, Mini-Splits are costly and need permanent installation, and Rooftop RV A/Cs are overkill for a van.

http://www.forestair.ca/en/serie-mini-anglais

This is a portable mini-split A/C that’s 8,000 BTUs & under a grand. I presume the price on the page is in  CAD ($900 +? tax), which at today’s exchange rate it’s about $700 US. It is possible to assemble yourself and the refrigerant hoses are a good length, flexible and look to be quick connects. All you need is a 3-4 inch hole for the hose run. Unfortunately it’s only sold in Canada for now, but that doesn’t stop us Americans from owning it. You’ll need to ship it to a friend or mailing address in Canada, then find a way to receive it.

https://vanlivingforum.com/showthread.php?tid=30489

I dig innovation, but I'm not sure that unit would do the job.  My newbie observations:

- The noisy compressor is outside with this unit, giving away stealth, right?
- Inside unit is 16x16x8, not bad, but the exterior unit looks to be slightly wider, so difficult to "hide" under the van for stealth.
- Where do they publish electrical draw for that 8k BTU and dimensions of the exterior unit? 
- Price is certainly cheaper than traditional MINI splits and install would be easier.

 

[bullfrog]

I haven't watched the videos but how are they cooling the compressor? It does create a lot of heat and requires air flow as well.

 

[AntiGroundhogDay]

I haven't watched the videos but how are they cooling the compressor?  It does create a lot of heat and requires air flow as well.

The fan motor inside the window AC unit remains installed and provides cooling to the compressor just like in normal operation. That's why under the can you install a weather proof fan from an ice machine on the underside of the van to cool the condenser.

 

[John61CT]

**Any** sounds from your van completely eliminates any hope of stealth

wrt residential area or passersby on foot.

If very well disguised as a fish or ice cream transport, maybe in a commercial area.

 

[John61CT]

Running from 1200W panel may work in full summer sun out in treeless rural areas, but no way in off season or developed areas.

And little solar charging going on with aircon on.

Really no point trying to run aircon from batteries

building a massive bank, each 100AH (50AH usable) dedicated to just aircon will only give about an hour's timeshifting until you need to crank up the genny anyway

And then you need hours of charging very early in the morning if you want your roof-full of solar to do its recharging

and during that time likely unable to run any aircon at the same time.

If you do go for the bank approach, then use LFP $$$$, and solar becomes pretty irrelevant, so maybe save some money there.

Just the electrickery will cost more than many here spend on their whole rig, possible but not practical.

The stealth fantasy just makes it silly.

 

[DannyB1954]

- Venting the condenser through the roof makes me itch.  The more intrusions w/ with the roof the more chance for leaks, but I see why you did it.
- I understand why you have the bulkhead separating the living space, but perhaps I can have my cake and eat it too with my design in that the GF and I will still get those Instagram p) pictures being able to see out the back of the van and with two people I'm want to preserve as much living space as possible w/ a dog as well.
- The side vents to your window A/C unit... they are there to draw air in the sides and blow it across the condenser as well as keep the compressor cooled, right?  If so (I'm by no means an expert), then do you worry about not having enough airflow behind your bulkhead when the backdoors are closed and the area is heating up in the hot sun?
- The "secure garage" you have with the bulkhead, are the rear doors more secure than the others or do u have a lockbox in that area?

Nice to hear it is running well during the day (when we most need it!).  I hope to attain the same and have a bit of battery for the first few hours of night when it still may be hot.  And of course when the sun goes down the compressor cycles on less.  We'll see.

The roof vents are covered by solar panels so direct rain can get in. They are also higher than the roof itself, so water will not get blown in when driving. there is an advantage to having a 35 year old van. Cutting holes in it doesn't devalue it a whole lot as even if it was pristine, the van is not worth much.

There is one vent on each side of the van and one in the back door and it has a 12" fan. heat rises, so as the air warms it goes out the top side vents and replacement air comes in through the lower door vent. The a/c itself acts as a vent fan because it pulls air in from the garage and pushes it out the top of the van. The setup worked well this summer here in Southern Nevada.

The generator does put out a lot of heat, so I may make an outdoor mount for when it is running. I originally wanted it inside because small generators are a high theft item. If I run just off of solar there is not much heat in the garage because the heat from the A/C is pushed out of the area and fresh air is pulled in to replace that air.

My a/c is pretty efficient and small. It takes 35 amps of DC running it off of an inverter. The amp hour ratings of batteries is based on a low drain over a period of time. To run the a/c for two hours you would probably need four 100 amp batteries or more to keep the inverter from tripping off from low voltage. I also used combination start / deep cycle batteries as more amps can be taken out of them quickly.

The video doesn't show it, but I removed the glass from the back doors and replaced them with 1/8" aluminum plate. If someone was real determined, they could get in with a saw, but not with a brick or coat hanger.

My build goal was different from yours. I wanted to reduce my living space so that it would be easier to heat and cool. All the stuff that couldn't care less about heat or cool was to go in the garage. I thought this may also help me keep the clutter down on the inside.