12v DC air conditioning idea

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stevezero

stevezero

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Jul 7, 2005
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For the AC experts out here...

Would a danfoss/secop BD35 or BD350GH r134 compressor (12 volt DC unit) be a viable starting point for an air conditioning system for a teardrop trailer? I figure it could be paired with common vehicle air conditioning parts.

Would the BD50F be a possibility too? I'd like to run an DC powered air conditioning system off of solar and battery, or off shore power when plugged in.
 
Would really need 4-5k btu max. Anything.larger would not allow the unit to dry the air, just make it cold.

I think a realistic load would be maybe 4-9 amps under full load, probably less than that. Would be interesting to see if it could be done with 200-400 watts of solar, and a 200ah battery. My envirocooler pulls less than 2 ah of current.
 
stevezero said:
Would really need 4-5k btu max. Anything.larger would not allow the unit to dry the air, just make it cold.
Click to expand...

I’m dumb. Please explain the “not dry” part. Rafael is vacationing, so I can’t ask him.
 
How central cooling works
Once warm air inside your home blows across the indoor evaporator coil, its heat energy transfers to the refrigerant inside the coil. That transfer, in turn, “cools” the air. The refrigerant is pumped back to the compressor where the cycle begins again. The heat absorbed by the refrigerant is moved outside your home while cooled air is blown inside. Moisture that contributes to humidity is also condensed out of the air. Your cooling system is usually combined with your central heating system because they share the same ductwork for distributing conditioned air throughout your home
 
So the Danfoss stops at the coolant line - you would still need an evaporator and a blower and then the return condenser?

You would maybe run the condenser outside and just build a line inside to your evaporator/blower?

Or is there more to this system?

Fun stuff!
 
Any inverter technology unit will work. I have a 4 ton that pulls 2 amps on start ups. So, you can get a 6000btu and never use the complete unit.
Too big of a unit will short cycle which doesn't allow to remove enough humidity out of the air. Inverter units have 400+ stages so you will never get the problem to be over sized.
 
Thought process currently. I've got a 5k wall mount unit in the front of the camper, but its 120volt.

Was wondering if I could cobble up a 12v system using a car evaporator on the outside, and a car condenser/blower on the inside. The evaporator could be behind a couple of alum panels to provide some protection during travel.

With 120v units you need a pure sine inverter and a lot of battery power. To run my ac off my modifi2d sine inverter and batteries, I could get about 80 mins out of 240 ah of battery, down to 50%.
 
This is something I've been trying to figure out for my slide-in camper. It too has a smaller 120v window AC unit that I'd like to use outside of shore power.

I'm with @45Kevin , have you eliminated the idea of a roof-mounted RV AC setup? They're cheap by comparison to the other types 12v AC setups I'm seeing.

If you don't want to go through all of that, can you open up the wall unit and see if it can be converted to run on 12v? Maybe the compressor is 12v already and you can figure something out for the controls.
 
The hardest part with the current RV units is size. Most are 10k or larger, and are way too big for a 5x10x5 camper. Granted, I've not dug deeply and looked at smaller units. Theres a company making self contained units (wall or ceiling) for semi trucks, for idle free stop time, but havent found a price or vendor
 
Remember that it sounds like a small 5x10rv but there is no insulation or sheet rock to avoid the heat gain. I will not worry about the size ( that didn’t come out right). But worry about the reliability. (Again this applies) i will check propane powered units too.
stevezero said:
The hardest part with the current RV units is size. Most are 10k or larger, and are way too big for a 5x10x5 camper. Granted, I've not dug deeply and looked at smaller units. Theres a company making self contained units (wall or ceiling) for semi trucks, for idle free stop time, but havent found a price or vendor
Click to expand...
 
Have you considered adapting the AC from a Prius or similar hybrid? The Prius uses an electric compressor.
 
Roxx said:
Remember that it sounds like a small 5x10rv but there is no insulation or sheet rock to avoid the heat gain. I will not worry about the size ( that didn’t come out right). But worry about the reliability. (Again this applies) i will check propane powered units too.
Click to expand...


Mine actually has some insulation in the roof. The walls and floor are 3/4 inch gelcoated marine ply, with a hpde plastic on the inner walls. roof is .040 aluminum, some foam insulation, and 1/4 inch birch ply.

The wall unit is cheap, reliable, and great for shore power or generator use. But needs 120 volt ac current.

This is some of the stuff my brain tries to sort out in the middle of the night when I cant sleep. It would be neat to have a 12v solution.

Propane isnt really a direction I'd wanna go either.
 
I looked into the Prius AC before and I believe the car battery powers it, not 12v. Car battery is like 200v DC.
 
You could always just put a Prius Battery in the rig! :) I was thinking about trying to find old ones and using them for home back up for a while. I did a lot of research on using my Prius as a whole house generator, as well - some people are doing it.
 
@stevezero - - Just go buy the Dometic - given @Roxx 's feedback it should simply use less energy and be fine in your smaller space regarding the humidity . . .



Then . . when it doesn't work, I will buy it from you for . .say $500 . . .or something.
 
Boondockers are using Tesla batteries for big rvs

Battleborn lithium are also popular for the wealthy.
Group 31, 100ah, 24 lbs. But, they are 950 a pop
 
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