Anyone tried this 12v cooling option?

[29chico]

The most efficient way to stay cool in seriously hot weather is to cool yourself NOT the air around you.

A good way to cool yourself is to use a phase change cooling vest and have at least one, or preferably two sets of the swap-able phase change pouches.  Most phase change pouches are good for 2-3 hours and then you swap out the pouches with some cold ones from your refrigerator.  If your refer is a compressor based 12v unit and it is powered by a solar system you would be using the sun to cool yourself.

 

[AngryVanMan]

Evap coolers work well in dry climates, the down side is water is often hard to get in dry climates, (you have to buy it). You can go through several gallons a day in an evap cooler.

That's one thing I've often wondered about, the ease of finding water in these more-remote BLM and NFS sites out west, are there no watering points at all on public land, and/or do you rely on commercial services to top up the tanks regularly.  That 5 gallon bucket cooler says it can use 2 gallons every 5 hours, which I would think is non-trivial if you plan to be "out" a week or more at a time.  I know I've heard about people carrying 5 gallon jugs into public restrooms, maybe on some of Bob's blogs or videos even.  Probably why he recommends tailoring your site selection to the weather conditions!

I was surprised to learn that evaporative coolers can be used in higher than 50% humidity, up to 80% in cooler (very limited) outdoor temperatures , but they just cool far, far less.  I guess one benefit of using in less ideal, more humid conditions is they would use less water overall.  I would think you'd start to get weary of mold issues if you keep running this type of cooler in more humid weather, though.

 

[highdesertranger]

I almost replied to this the other day. I travel the western deserts. you CAN always find water, there are hundreds of thousands of springs throughout the desert. this water is considered non-potable. but for non consumption it's fine. so for a swamp cooler or just plain soaking yourself it's great. I boil it and wash dishes all the time. I use it for processing paydirt. I run it through a crude filter(cotton towel) first. you can also run it through a filter and use it for drinking.

the trick to finding the springs are the USGS maps. these maps are very detailed. I have tried all kinds of other maps and find them lacking. Delorme and Benchmark are ok for generally getting from point A to point B. but if you want the detail in between A and B, nothing beats the USGS. in fact all the other maps are USGS based. they just leave out a lot of the detail. BTW the old out of date 15 minute maps are the best. it seems the USGS is stating to edit out a lot of info. highdesertranger

 

[drewker]

The most efficient way to stay cool in seriously hot weather is to cool yourself NOT the air around you.

A good way to cool yourself is to use a phase change cooling vest and have at least one, or preferably two sets of the swap-able phase change pouches.  Most phase change pouches are good for 2-3 hours and then you swap out the pouches with some cold ones from your refrigerator.  If your refer is a compressor based 12v unit and it is powered by a solar system you would be using the sun to cool yourself.

wow now that is thinking out of the box. i am gonna check it out

 

[drewker]

That's one thing I've often wondered about, the ease of finding water in these more-remote BLM and NFS sites out west, are there no watering points at all on public land, and/or do you rely on commercial services to top up the tanks regularly.  That 5 gallon bucket cooler says it can use 2 gallons every 5 hours, which I would think is non-trivial if you plan to be "out" a week or more at a time.  I know I've heard about people carrying 5 gallon jugs into public restrooms, maybe on some of Bob's blogs or videos even.  Probably why he recommends tailoring your site selection to the weather conditions!

I was surprised to learn that evaporative coolers can be used in higher than 50% humidity, up to 80% in cooler (very limited) outdoor temperatures , but they just cool far, far less.  I guess one benefit of using in less ideal, more humid conditions is they would use less water overall.  I would think you'd start to get weary of mold issues if you keep running this type of cooler in more humid weather, though.

yea the water replenishment looks like it would be a problem, plus mold accumulation i've read

 

[drewker]

i'm in utah now for work. i found an excellent spot to escape the heat in nv, but now i am no longer there. utah seems even more brutal than nv with regards to the heat/sun. i am doing tech work and will be in a different town in utah every night for the next month. god i miss the weather in the northwest, i mean utah hardly even has any shady spots. i actually just contacted an airbnb host, last night i got bitten by these desert flies and the breeze just wasn't happening. i want to re-iterate that reflectix has been useless for me. i have not noticed ANY discernible difference with it on the windows, in fact i almost think it has made the van hotter.

 

[IGBT]

Hard to beat a small 6000 BTU $99 window A/C and a kilowatt or more of solar.  Especially now solar is $0.60 a watt.

Today our window unit ran 8 hours just off the sun and kept the camper at 71 in 92 degree heat.

A mini split is overkill IMO

 

[drewker]

Hard to beat a small 6000 BTU $99 window A/C and a kilowatt or more of solar.  Especially now solar is $0.60 a watt.

Today our window unit ran 8 hours just off the sun and kept the camper at 71 in 92 degree heat.

A mini split is overkill IMO

Hi there, I agree. Again the heat is making me miserable, the good news is I have plenty of work. If I could get comfy in the van it would be a huge relief. So I already saw $99 a/c... how much for that solar setup approximately -  I am totally unfamiliar with solar technologies and what it can do. How much would I need, how much would it cost? Do you have to put the ac the window or can the window unit sit inside the van? Hanging it outside the van looks so ghetto imo, and kills stealth

 

[DannyB1954]

Some put the window A/C in a cabinet, and the only thing on the outside is a grill. One could make the cabinet a tight fit, then just drill holes in the floor where the condenser air inlet and outlet are. Put a screen over the hole for critters.
My experience with A/C is you need about 60 amps at 12 volts to make it happen. This comes out to 6 amps at 120V. about 1 1/2 times more is used during starting. For a van, I think this would be a most difficult task to do with solar. I just bought a van, I might put a trailer hitch cargo rack on the back with a generator. The best thing is to be where it is neither too hot or too cold.

 

[sushidog]

Hard to beat a small 6000 BTU $99 window A/C and a kilowatt or more of solar.  Especially now solar is $0.60 a watt.

Today our window unit ran 8 hours just off the sun and kept the camper at 71 in 92 degree heat.

A mini split is overkill IMO

The most efficient 5000 btu window ac I've found in the $100 range is this one at 11.1 eer https://www.amazon.com/Frigidaire-FFRA0511R1-Window-Mounted-Mini-Compact-Conditioner/dp/B00W2KG92Y?
ie=UTF8&linkCode=ll1&linkId=c6e09eeb26c5d99672250e99f03bcf9c&ref_=as_li_ss_tl&tag=searchnet-20 It consumes 336 watts on high and around 400 watts on start-up. Assuming an 85% efficient inverter this means it draws 33 amps at 12v to produce 5,000 btus of cooling (40 amps surge at start-up). 1,000 watts of solar panel will produce about 45 -50 amps if mounted flat (for around 5 hrs/day) sufficient to power the panels in direct sun but maybe not enough to charge batteries for evening use. Remember that a 5,000 btu ac will be running at or near max all day to keep the van cool, but it is the cheapest option.

For comparison, a 12,000 btu mini-split (for around $2,000) might indeed be "overkill" in a van, but this type of compressor is a variable speed design, so while it draws 46 amps wide open (to make 12,000 btus of cooling) it will probably be running at less than 1/2 speed most of the time consuming about 23 amps, drawing 1/3 less power in a real world application. It doesn't need an inverter as it is a native DC appliance so you'll save about $200 on the cost of a suitable PSW inverter too.

They do make smaller, 8000 btu 12v ac units for trucks and mini-busses, like the King Air and Arctic Breeze units, but they are expensive too (around $1,500) and their efficiency falls between the high-end mini-split and a cheap window AC.
Chip

 

[sushidog]

Here's another 12v DC air conditioner designed for hot rods and custom installations that might be of interest: http://www.cruisencomfortusa.com/wp-content/uploads/2016/07/HOT-ROD_FLY_2016.pdf

They are about $2,800 though. Ouch!

Chip

 

[jimindenver]

The replacement for my energy star 5000 BTU A/C uses 410 watts. I could run it off of two 250 panels. It runs $200 but you would save that by not getting the third panel and larger controller.

 

[drewker]

Ghetto or not you will need to have the AC inside side on the inside of the van and the outside part.... outside. If you had the complete unit inside the van it would effectively become a heater. Same principle as leaving the refrigerator door open as in your original post.

Guy

yeah good point. maybe i can get one that isn't so obvious. i felt the back of the ac unit at walmart, def generating heat...just hoped that maybe the cold would overcome it, but yeah that is whats up

 

[drewker]

Some put the window A/C in a cabinet, and the only thing on the outside is a grill. One could make the cabinet a tight fit, then just drill holes in the floor where the condenser air inlet and outlet are. Put a screen over the hole for critters.
My experience with A/C is you need about 60 amps at 12 volts to make it happen. This comes out to 6 amps at 120V. about 1 1/2 times more is used during starting. For a van, I think this would be a most difficult task to do with solar. I just bought a van, I might put a trailer hitch cargo rack on the back with a generator. The best thing is to be where it is neither too hot or too cold.

agreed. but the job i'm doing pays 3 times as much as anything i could get in the northwest right now. an ac would make everything copacetic again.

 

[jimindenver]

In so class B's a window like A/C is mounted in a box with a grill showing outside. I have seen a DYI box for a RV on one of the forums. It doesn't have to hang out.

I considered mounting mine under a bunk so that I could open the storage door when I needed to run it. The circulation was off so we run it in a front window.

 

[sushidog]

The replacement for my energy star 5000 BTU A/C uses 410 watts. I could run it off of two 250 panels. It runs $200 but you would save that by not getting the third panel and larger controller.

Two 250 watt panels (500 watts of solar) produce about 25 amps during peak sun (not all day) 410 watts divided by 12 volts is 34 amps. No inverter is perfectly efficient. Most are 85% or so, so that inverter will draw 40 amps to power that AC. This means you will need at least 1,000 watts of panels if you want to put some power back into your batteries. I doubt a 5,000 btu ac will cycle much, but will run most of the day. If you want to power your AC at night, to sleep then you would need 8 GC-2 golf cart batteries, assuming it will cycle more in the cool evenings, so as not to deplete your battery bank.

Running an AC on solar takes a lot of juice, but is doable. But don't take my word for it, here's some guys with real world experience.




Here's a guy with a 6000 btu window AC running on 1260 watts of solar. With 6 golf cart batteries, starting at a full charge, he says he can get around 4 hours at night cycling them down to around 50%.


And another van mounted solar ac video from the Nomadic Fanatic.


Chip

 

[ToddandHeather]

That's one thing I've often wondered about, the ease of finding water in these more-remote BLM and NFS sites out west

http://www.findaspring.com/

 

[jimindenver]

Chip

I run my 5000 BTU A/C pulling 450w off of 750 watts flat with no loss to the bank. It pulls between 33 and 38a inverter and all, the system puts out 40-50 amps. It ran the A/C from 10 am to 5 Pm in 94F heat on a battery that read 12.4v at the start. The last two hours were as the light slipped and it took that long to get the dieing battery down to 12v under load.

Peak for one of my 250w panels is 18.5a , flat will cost you so move up to a 275 or even 300w panel. You will be pushing 20a and a pair will cover the 410w.

 

[IGBT]

Our window unit on our homebuilt RV is mounted totally inside with just a grill showing on the outsid (a furnace intake vent from Lowe's).  I designed and fabricated a aluminum duct to channel outside air into the inside sides of the A/C and exhaust it through the same exterior grill.  Works amazingly well.

 

[drewker]

i tried a 20 inch box fan last night. worked fine with my regular inverter but did not raise my comfort level much at all as the night air was hot in salt lake last night... i am willing to spend up to $600 to get this ac business worked out. 5000 btu ac = $120ish, so I just got to figure out how to power it. i like the battery bank idea but i don't know, how many would i need. if i make this investment i would want to be able to power the ac in the summer and a heater in the winter. don't have much else i need to power.... i saw an ac model for $229 at lowes - it has that hose attachment that goes out the window. seems like a more elegant and stealthy solution than taking out a window... how in the world did people cope without ac for millions of years? we are so spoiled but i mean i would rather have ac than a shower.