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How to make homemade 12v air conditioner?

14K views 67 replies 19 participants last post by  AstroWill 
#1 ·
Van is full insulated , has a roof vent to let heat escape , Windows are covered with insulation to keep suns heat from coming in , has a windshield shade .
How can i make a homemade 12v air conditioner to use for camping?
I was wondering if I could build something from taking the complete air conditioning
System out of a vehicle at pick n pull and then building it into a case and then turn the compressor with a small gasoline motor.
I already have a honda 2000 generator and window unit but it uses to much gas.
 
#27 ·
97cargocrawler said:
Lumpy said:
If it helps the perspective -
Still you cannot run the A/C without shore power.
Lump
So it won't even fire up or?
It's physically disabled unless you're on shore. My guess would be it has to do with the startup current rush.

But you'll figure out a workaround. I'd recommend a lot of Farads on the motor start.

Cooling a comparitively tiny space. I imagine that would want to cause the thermostat to cycle more frequently than if it were larger. That cycling is, of course, the big current suck.

Lump
 
#28 ·
Lumpy said:
97cargocrawler said:
Lumpy said:
If it helps the perspective -
Still you cannot run the A/C without shore power.
Lump
So it won't even fire up or?
It's physically disabled unless you're on shore. My guess would be it has to do with the startup current rush.

But you'll figure out a workaround. I'd recommend a lot of Farads on the motor start.

Cooling a comparitively tiny space. I imagine that would want to cause the thermostat to cycle more frequently than if it were larger. That cycling is, of course, the big current suck.

Lump
Could you prevent the cycling by relocating the thermostat outside in the heat?
Idk but I think I heard of a guy that would run a Air conditioner for 8 hours and he started out with 8 fully charged 6volt golf batteries , after 8 hours he needed to recharge. .
I was thinking if you had a small very well insulated box and crank the air conditioner balls out for a hour and a half it should remain cool for a few hours and then start the a/c up again every couple hours to maintain a half way decent temp , also like you mentioned Lump install that hard start capacitor to help from sucking battery juice everytime you restart.
 
#29 ·
Lumpy said:
97cargocrawler said:
Lumpy said:
If it helps the perspective -
Still you cannot run the A/C without shore power.
Lump
So it won't even fire up or?
It's physically disabled unless you're on shore. My guess would be it has to do with the startup current rush.

But you'll figure out a workaround. I'd recommend a lot of Farads on the motor start.

Cooling a comparitively tiny space. I imagine that would want to cause the thermostat to cycle more frequently than if it were larger. That cycling is, of course, the big current suck.
Lump
I guess the part that confuses me is that I already did it and posted those pix to show how little the AC is pulling on my inverter. You can see the power panel for the inverter there on the bed. There were few cycles because the space is so small and stayed chilly. I had it running for 45 minutes. About 35 of that was in eco mode with low fan and I was cold. Then I kicked everything into arctic mode and froze my nuts. I don't know how long I could keep it going like that on batt juice alone but current rush wasn't an issue at all. The AC didn't struggle to kick on the compressor. Maybe that would be an issue with fewer batteries.

I didn't plan on showing this because I didn't finish, but here's a video explaining my setup before the test:

 
#31 ·
Mine will run on batteries and solar. I don't plan on finding any sort of gas after the apocalypse. Running a commercial (200lbs or so) unit off a small engine (50lbs?) is what, maybe 51% efficient with the van static? Start to drive with all the weight and poof! there went any advantage you gained, lost in fuel economy. I think window shaker is the way to go...just need a convenient way to mount it.
 
#32 ·
Really? You want to go thru all this when it's been done a long, long, long time ago? Not to give my age away but I lived with both of those and loved them both while crossing the Mojave, as a 9 yr old in the back seat. Just build in a 12v fan on the tube and you're good to go. At 70 mph that tube really cools. Simple!
 

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#33 ·
97cargocrawler said:
I tested my wall AC a few weeks ago with battery power and a 2,000W inverter. I ran it for about 45minutes on a 90*+F day and cooled the van down to about 70* and I have zero insulation. The walls of the van were still hot to the touch from inside.

I wanted to make sure I could power the AC before I tore it apart and built it into the van. I have 300lbs of battery power hanging above the rear axle. I'm still not sure about running it all day long in conjunction with solar. This test was my worse case power scenario and it passed so I'm going forth with my plans to mod the window shaker. If I didn't have a rear tire carrier I think I would just make a huge hole in the rear drivers side door and pop it through when needed.
Sounds like your a/c will handle the cooling load and your inverter will handle the a/c...Sweet! You will need to have a drain for the condensation the evap. coil will create. Shouldn't need more than a 3/8 drain tube, just don't forget you'll need to clean it out occasionally. I once cut a new water cooled heat pump w/electric backup heat, in half. Compressor, water heat exchanger and electronics under a water heater shelf, Blower, evap. coil and electric heat kit in a suspended ceiling. We extended the copper "lineset" ran it all through walls. That was six years ago and it still checks out with near new specs./runs like new. Just make sure you match the factory airflow at both coils and your system will run fine. The standard is 350 cfm per ton(12,000 btu) of system capacity.*EDIT* 350 cfm per ton at the evap (indoor) coil* You could also use variable speed motors and dial it in that way, but it kinda leaves a door open for failure if you know what I mean. Good luck! Steve
 
#34 ·
supersteve said:
97cargocrawler said:
I tested my wall AC a few weeks ago ...
Good luck! Steve
Thanks! I'm hoping to remove the luck part entirely. I have done tons of research on AC in the past month and bought just about every friggin tool a professional HVAC tech would have. At this point I could F up a few AC installs, replace with new units and still not come close to touching the amount I have spent on tooling to gear up for this mod. I'm not going to cut any corners, except maybe out of the van. When I'm done I might as well go to HVAC tech school and get licensed because I will literally have everything but the blue slacks and shirt. Soon to be adding a plethora of pix to the "show us your tools thread."
 
#36 ·
I spend an hour in my van every weekday eating my lunch and then taking a nap. In the summertime temps in the van easily get up to 110*F. That's a wee bit uncomfy and I definitely do not like returning to work looking like I just ran a marathon. To combat the heat I open the doors/windows, turn on a fan, remove the shirt and boots and stack blue ice packs on my chest and behind my neck. Works great aside from the stiff neck! I'd so much rather just flip on the AC and have a little privacy. I have woke up to strangers watching me sleep. Gotta love Hollyweird.
 
#38 ·
97cargocrawler said:
I spend an hour in my van every weekday eating my lunch and then taking a nap. In the summertime temps in the van easily get up to 110*F. That's a wee bit uncomfy and I definitely do not like returning to work looking like I just ran a marathon. To combat the heat I open the doors/windows, turn on a fan, remove the shirt and boots and stack blue ice packs on my chest and behind my neck. Works great aside from the stiff neck! I'd so much rather just flip on the AC and have a little privacy. I have woke up to strangers watching me sleep. Gotta love Hollyweird.
1990 or there abouts I worked on replacing the Mianus Bridge in S.W. CT. At the time it was a long commute so I stayed there during the week in my '70 econoline high top camper. The tugboat captain had a cabin on his boat and he did the same, during the week we would BBQ and head to Stamford for the nightlife, once in a while I would oversleep. :sleep:

More than once I woke to the sound of my crew watching TV, the back doors of my van opened and 3-4 guys drinking coffee watching the news.

At least my apprentice had the decency to save me a cup. :thumbup:
 
#40 ·
CargoCrawler said:
I guess the part that confuses me is that I already did it and posted those pix to show how little the AC is pulling on my inverter. You can see the power panel for the inverter there on the bed. There were few cycles because the space is so small and stayed chilly. I had it running for 45 minutes. About 35 of that was in eco mode with low fan and I was cold. Then I kicked everything into arctic mode and froze my nuts. I don't know how long I could keep it going like that on batt juice alone but current rush wasn't an issue at all. The AC didn't struggle to kick on the compressor. Maybe that would be an issue with fewer batteries.

I didn't plan on showing this because I didn't finish, but here's a video explaining my setup before the test:

Webcat wrote
Starting the air conditioner should be no problem if you have a big enough invertor which you do , the real test is how long it will run until your battery bank voltage reads 12.06 volts.
My guess would be 4 hours but who knows maybe it'll run 10 hours , I would really like to see.
I know without that air conditioner your batteries will last a long time because I only run 2 golf batteries and I went like 6 months of dry camping and the only charge my 2 batteries ever got was from my alternater driving maybe 4 miles a day and maybe 15 miles on the weekends.
I was running about 5 amps worth of L.e.d lights , stereo , tv , phone charger , water pump briefly , everything was 12 volts ,,,,this year I added a fridge of 3.75 amp draw.
I'm curious how my battery bank is going to cope with the amp draw of this fridge .
Before I never ran low on power but I honestly never even paid attention to it much.
I always had the power I needed.
 

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#41 ·
Throw two solar panels on the roof. Buy a few portable panels too. There should be enough leftover power during the day to keep the fridge running while the batts charge.

I hope I never need 4 hours of AC. If I'm out in the middle of nowhere I hope to be running around naked enjoying the sunshine and outdoors. :D
 
#42 ·
97cargocrawler said:
I'm thinking of taking a regular window unit and reconfiguring it, possibly with either a 12v motor or running it off an inverter. Just so happens I have a spare one laying around begging for me to rip it apart and tinker. I want it to be less box like and not stick out a foot from the van. Might be a while before I get to that project though.
I bet you could fit a 5000 btu window shaker where your license plate is , 2 inches would stick out 5 inches in the door and maybe 7 inches in the van , wouldn't take up that much interior space , only be in there for 3 months any way , less power requirements.
Plate would go on the bumper.
Way easier then making a custom air conditioner
 
#43 ·
webcat said:
97cargocrawler said:
I'm thinking of taking a regular window unit and reconfiguring it, possibly with either a 12v motor or running it off an inverter. Just so happens I have a spare one laying around begging for me to rip it apart and tinker. I want it to be less box like and not stick out a foot from the van. Might be a while before I get to that project though.
I bet you could fit a 5000 btu window shaker where your license plate is , 2 inches would stick out 5 inches in the door and maybe 7 inches in the van , wouldn't take up that much interior space , only be in there for 3 months any way , less power requirements.
Plate would go on the bumper.
Way easier then making a custom air conditioner
But where's the fun in that?!!!! I already bought a 25gal tank of R410A, a professional set of gauges, scale, recovery compressor, recovery tank, vacrometer, bullet valves, an acetylene torch, pipe swaging kit, leak sniffer....lucky I have a vacuum pump already. I still need a set of lines, filters and some fans.

If I didn't have the tire carrier I would have cut a hole in the rear driver side door. But since I do...and even the window area is occupied...it's time for experimenting. I love to tinker so this is just a crazy expensive experiment. Clearly nobody else is going to spend $2,000 on tools to mod a $130 air conditioner. But in my case the size and weight are paramount issues so that's my motivation and $$$$ doesn't matter.
 
#45 ·
Wow you guys are really going at this A/C stuff.

my only thought it so to look at how electric cars handle their AC, especially diy cars.

Other than that, could you not throw a DC motor on the front of a standard car A/C compressor then use either the vans condenser and the such or use a separate set?
 
#47 ·
Semi tractors for years had a roof A/c unit that was electric and self contained. It had a big 12V cable running down the back of the cab to the battery box and a hole in the roof with the evap and controls right above the driver. If you ever saw a semi tractor with a big box on the roof, it had A/C. If you have a semi truck junkyard nearby you should be able to get one of these units cheap and they almost always work. They were so reliable it's crazy.
 
#48 ·
Zebediah III said:
Semi tractors for years had a roof A/c unit that was electric and self contained. It had a big 12V cable running down the back of the cab to the battery box and a hole in the roof with the evap and controls right above the driver. If you ever saw a semi tractor with a big box on the roof, it had A/C. If you have a semi truck junkyard nearby you should be able to get one of these units cheap and they almost always work. They were so reliable it's crazy.
There used to be a giant semi junkyard nearby. It closed last year. =( I'm trying to avoid a rooftop AC, because my van is already almost 9 feet high. I've been looking at dog house units. Since the vans are small, they may work well enough.

This thing is 9"x8"x12". 1400btu. I may try this out and use the stock rear ducting from a van that came with it.

http://cozywinters.com/shop/dog-house-a ... oCfYvw_wcB
 
#49 ·
Your looking at approx 220 - 240 cu ft bare interior in the van.
You would need the capacity of 4-5 of those units.
Build in some cabinets and bed could cut that in half.
 
#50 ·
dryhumor said:
Whatever happened with this?

My next project is a bbq, an aux A/C, and a margarita/slush machine. When I'm parked at music festivals, I want to be comfortable.
With your clearance I'd bet you could mount a window unit underneath and duct it in through the floor.
 
#51 ·
My brother and I have come up with a simple solution to cool off his Teardrop it might work in our vans.
My brother has a Solar panel and battery setup and he also has a Dometic Freezer(Yes it was not cheap) But his idea is to make Ice during the day with Solar power and use the Ice for Cooler at night. He can also use the ice to cool water for one of these;
DIY AC

Using a 12v pump and fan this is totally doable.

Sorry not the best video but you get my point. If you have an ice cooler already in the van just put the pump and pipe the Copper or PVC tubing into it.
 
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