Air Conditioning on battery pwr alone? Well, on paper. . .

[wingloader]

I just bought a 3000 watt pure sine wave inverter. Pure sine wave inverters are more expensive but you gain efficiency AND you won't burn up the motors in your appliances like a cheaper inverter will.

I have an AutoCraft Marine / RV 12-Volt Deep Cycle Battery, Group Size 27, 600 CCA. I hooked the battery up to the inverter with a short piece of #6 wire and plugged in my Frigidaire FFRA05L1R1, 5000 btu window shaker. It fired right up. It is rated at450 watts.

The inverter has an auto cutoff at 10.6 volts. I ran it on max cool with the fan on high until the inverter kicked off. It ran about an hour. This is what the calculated run time is according to this online calculator (VERY COOL....you must try it!) http://www.donrowe.com/power-inverter-f ... m#how_long

I like it COLD in my TD. Like...I have to use a comforter to keep from being cold when I am sleeping. When I have shore power, I run the thing on MAX everything. It gets damn cold in there and I LOVE it.

Using that battery, I would need 7.5 batteries in parallel to run the AC the way I like it for 8 hours.

Resolution? Shore power. I basically have a monster inverter that will be WAY under utilized.

[APCROSS]

I saw this battery powered portable air conditioner on Kickstarter a few months ago. Looks perfect for a teardrop:

https://www.kickstarter.com/projects/1253665084/zero-breeze-the-worlds-coolest-portable-air-condit?ref=nav_search

That said, I've been screwed on some Kickstarter projects on products that are never delivered. So we'll see if this thing actually happens. (I didn't back this project, though.)

[Syberia]

You might try a "redneck air conditioner" - a Styrofoam cooler full of ice with a 12v fan blowing air in one side, over the ice, and a hole for it to escape the other side. You could probably even get fancy and make it thermostatically controlled. The ice might not last all night, but should at least be enough to take the edge off and let you get to sleep until things cool down naturally. This is probably not ideal if the main goal is humidity removal.

Of course, you have to have the ability to buy ice...

[Aguyfromohio]

I saw this battery powered portable air conditioner on Kickstarter a few months ago. Looks perfect for a teardrop:

https://www.kickstarter.com/projects/1253665084/zero-breeze-the-worlds-coolest-portable-air-condit?ref=nav_search

That said, I've been screwed on some Kickstarter projects on products that are never delivered. So we'll see if this thing actually happens. (I didn't back this project, though.)

I'm naturally skeptical of claims that there has been some breakthrough in devices that are mature and well understood like small air conditioners.
I spent a bit of time googling around to satisfy myself the zero breeze never got off the ground and was a crazy idea.
Looks like I'm wrong about that.

The basic technical claims seem like solid engineering.
It's just a very tiny conventional air conditioner at 1100 BTU/hr, consuming 150 watts.
That's just about exactly 1/5 the cooling and 1/5 the power draw of the little 5,000 BTU Frigidaire units we bought.

It's a separate question if that's just too small to cool even a tiny trailer, but the unit seems plausible.
Of course there are unlimited ways to mess up manufacturing any product, so quality and reliability remain to be seen.
But it looks pretty nice so far.
I don't think you can buy one today, but they claim they will be for sale next month.
Perhaps at the end of summer there will be decent reviews we can read of production units.

[Socal Tom]

If the issue is just not running a generator at night, then the "ice bucket" A/C unit coupled with an ice maker would probably be a decent solution. 1 Lb of ice has roughly 200 BTU, so 10 lbs of ice should meet your cooling needs for a night. You can pick up an ice maker that claims to make 26 lbs per 24 hours on amazon for $159.
Tom

[KennethW]

I was thinking a twist on the swamp cooler thing. What if One uses a evaporative water chiller on the roof(set on the roof when parked) and a small radiator in the cabin. The water would be pumped to the top of the pad. Cooled down. Then flow down in the bottom of the radiator out the top and down into the reservoir(with the condensation) to be pump up again. I think you should end up with a cool dry cabin? Any thoughts? I may try a set up if I get some positive feed back.

[Socal Tom]

I was thinking a twist on the swamp cooler thing. What if One uses a evaporative water chiller on the roof(set on the roof when parked) and a small radiator in the cabin. The water would be pumped to the top of the pad. Cooled down. Then flow down in the bottom of the radiator out the top and down into the reservoir(with the condensation) to be pump up again. I think you should end up with a cool dry cabin? Any thoughts? I may try a set up if I get some positive feed back.

With 10% humidity you can get about a 10C ( about 18F) degree drop in temp. ( about
If you use that to cool water, then pass it through a heat exchanger, then your 86F water becomes 68F, ( less some temp loss for ineffecincy of the transfer) and when you pass 86F air over the 75F heat exchanger you still end up with about 80F air. Now, if you were to use a bucket of ice instead of the Evap cooler, it would provide air about 40F ( about the same as AC) but for a typical tear drop you would probably need about 3-4000 BTU per hour to keep that up. 1 lb of ice is about 150 BTU per pound, so that means about 20 to 30 lbs of ice per night. BUt as humidity increase the temp change is smaller at 50% humidity it is only 10 degrees and you probably wouldn't feel difference
Edit ( corrected when I saw the image was C not F)

[Socal Tom]

There are several smaller 12V A/C systems available now. Here is a link to a discussion on EXPO http://forum.expeditionportal.com/threa ... -Well-Cube. The short answer is that the one at the top makes 3250 BTU, but uses 36 AMPs/hr.
That would mean you would need 3 or 4 batteries ( 100 amp @50%) to make it 8 hours, and have a way to recharge them before the next night. I think an alternative to consider would be to use the ice chest/AC and bring a generator and an ice maker or two.
This one says is uses about 100W, so a 1 or 2KW quiet generator would pull a couple of them and each one can makes 26 lbs in 24 hours. Two of those would get you more than enough ice, and a with a 12V fan to circulate the air you would have a cooling system that could last most or all of the night, and no worries about battery charging, and you could reuse the water the next day to make ice again. With the proper design the Ice/AC unit would also act as an Evap cooler. The only thing you might consider adding would be a simple thermostat to control the fan, so that you didn't over cool the interior and freeze yourself out.
Tom

[Aguyfromohio]

I saw this battery powered portable air conditioner on Kickstarter a few months ago. Looks perfect for a teardrop:

https://www.kickstarter.com/projects/1253665084/zero-breeze-the-worlds-coolest-portable-air-condit?ref=nav_search

That said, I've been screwed on some Kickstarter projects on products that are never delivered. So we'll see if this thing actually happens. (I didn't back this project, though.)

I'm naturally skeptical of claims that there has been some breakthrough in devices that are mature and well understood like small air conditioners.
I spent a bit of time googling around to satisfy myself the zero breeze never got off the ground and was a crazy idea.
Looks like I'm wrong about that.

The basic technical claims seem like solid engineering.
It's just a very tiny conventional air conditioner at 1100 BTU/hr, consuming 150 watts.
That's just about exactly 1/5 the cooling and 1/5 the power draw of the little 5,000 BTU Frigidaire units we bought.

It's a separate question if that's just too small to cool even a tiny trailer, but the unit seems plausible.
Of course there are unlimited ways to mess up manufacturing any product, so quality and reliability remain to be seen.
But it looks pretty nice so far.
I don't think you can buy one today, but they claim they will be for sale next month.
Perhaps at the end of summer there will be decent reviews we can read of production units.

Well, Zero Breeze is manufacturing and selling units. It seemed worth an updated post
Here's a review

https://www.wired.com/review/zero-breez ... nditioner/

Bottom line on review -it's big and heavy and noisy but it does work, producing truly cold air.

A little 5,000 BTU window air conditioner cost $150 or less. That gives you 33 BTU of cooling for every dollar you spend.
The Zero Breeze is 1,100 BTU and costs $900. That's a smidgen more than 1 BTU for every dollar you spend.
So by that yardstick the Zero Breeze is 30 times as expensive as a small window unit.

But it does in fact work and did actually make it to market, good on them.

[theoldwizard1]

12VDC compressors have been available for several years. (Technically they are not 12VDC, they have their own dedicated 3 phase inverter.) They work quite well but are expensive. There are only a handful of companies that have taken this technology and packaged it into an AC or refrigerator.

It is still probably cheaper to find a high efficiency 120VAC window AC unit and buy a good pure sine wave inverter along with four 6V golf cart batteries (over 400 Ah @ 12V). Charging the batteries is another discussion.

[Shadow Catcher]

The 5000 BTU does a good job of cooling, we do have 1.5" of EPS insulation and runs about 40% of the time in 90 Degree weather.