pondering on air conditioning...

[Trackstriper]

leadbelly,

I'm running into the same issues that your are and have been thinking about this for a while. The small dehumidifier that you indicated is a peltier device and they aren't very efficient. Same device that is in the thermo-electric coolers. I had toyed with ganging up several peltier chips with enough heat sink to cool my small area. There are plenty of these chips and devices available on eBay. Just didn't seem to be able to live with the theoretical power draw.

I did see a small compressor based "personal air conditioner" that supposedly generates 1000btu with a 2.1 amp draw at 120v for a consumption of 250w. That's less than the Pet Cool. The unit seems to be a cross between a small AC and a dehumidifier and dumps the heat off the backside of the unit for no net cooling. BUT...if you could dump that heat outside as you suggested it might work. It's a relatively large unit and costs about $200 but it draws less juice than the Pet Cool and it does do work as you can see from the dehumidification specifications. As others have indicated, you would still need some battery behind the scheme, perhaps double your battery capacity. Check out: Amcor model APC 2000E.

http://www.amcorgroupusa.com

J.B.

[Alphacarina]

. . . . also consider, that as the voltage decreases in the battery with usage, the amperage will go up to maintain the wattage and at the end of that 6 hours, you may be drawin' 60Amps or more...

Don't think it would get quite that bad, Jack

Most inverters can't cope with the extra current draw low battery voltages would subject them to, so they usually shut down around 10.5 volts . . . . but sucking a lead acid battery down to 10.5 volts isn't really good for it anyway, and a voltage that low means you're about at the end of your cool . . . . one way or another

Another thing to keep in mind with any high load, inverter powered devices is that your total run time depends on starting with a fully charged battery and since most all regulators taper off a lot toward the end of the charge, putting 100 AH back into the 205 AH battery could take as much as 8 or 10 hours of charge time - Maybe not a problem if you're driving for 8 or 10 hours each day after you've used the cooling overnight, but you'll surely find you won't always have a fully charged battery to begin the night with each time and that can also put a crimp in your cool - Not to mention that you probably need the battery for lights, radio, TV and maybe refrigeration too . . . . gotta keep the beer cool somehow, you know

I've had a couple of large sailboats over the years, all of them with large inverters and even larger battery banks (even 200 watts of solar panels on my last one) but even with lots of . . . . experimentation and several hundred amp hours worth of batteries, I've never found that powering large loads for extended periods with a battery/inverter setup was a very practical thing to do - It's almost like chasing perpetual motion . . . . a great idea, just not one that's easily accomplished

Don

[madjack]

...you're right Don...it PROBABLY won't get that bad...the point I was trying to make is that the current flow will not stay the same but increase as voltage drops...a consideration for the input wiring(from battery)...personally, I am waiting for someone to come up with a whizbang that connects to the trailer axle by 2 bolts, that charges the battery, runs the AC, connects to WiFi and satellite, gives the tow vehicle a push and costs less that 20 bucks...oh yeah, if it could cure the common cold and dispense beer as well that would be a nice plus
madjack

p.s. one of my Dads best friends, spent his entire life, tinkering in the garage, trying to invent a perpetual motion machine...ya know what he came up with...............nothin'...MJ

[ARKPAT]

As Crazy Guggenheim ( Jackie Gleason Show ) said; "I'll - ll - ll - ll drink to that."

Pat

[pbbelly]

...trying to invent a perpetual motion machine..

Perpetual motion is impossible, cooling 96 cubic feet 30° cooler than the ambient air temperature isn't. Doing it without a noisy generator or a land line may be impossible with current technology, but it wasn't that long ago that the 12v refrigerators (and zillions of other pieces of technology) that are available now were fantasy.

I imagine when all is said and done that I will resort to:

(A.)filling my meager cargo space with a generator and a/c and carrying a rooftop carrier for my other gear or
(B.) Stop being so anti-social and start camping in the electric hookup campgrounds with the masses and all of their amenities...but that is contrary to why I go camping-to get away from the masses and the trappings(I know, you're thinking "what about air conditioning?"-I'm being a hypocrite).

Argh!

I guess the third alternative is only camp where/when the humidity is low!

In the mean time I won't give up too easily...I'm from Missouri-you have to Show Me![/quote]

[pbbelly]

leadbelly,



I did see a small compressor based "personal air conditioner" that supposedly generates 1000btu with a 2.1 amp draw at 120v for a consumption of 250w. That's less than the Pet Cool. The unit seems to be a cross between a small AC and a dehumidifier and dumps the heat off the backside of the unit for no net cooling. BUT...if you could dump that heat outside as you suggested it might work. It's a relatively large unit and costs about $200 but it draws less juice than the Pet Cool and it does do work as you can see from the dehumidification specifications. As others have indicated, you would still need some battery behind the scheme, perhaps double your battery capacity. Check out: Amcor model APC 2000E.

http://www.amcorgroupusa.com

J.B.

Interesting! they're available on ebay from $179...Thanks!

pbbelly

[mrchuc]

I am waiting for delivery of a 4-wide teardrop from Little Guy. At some point I am pretty sure I will want to install AC (Missouri summers are miserable.)

Am I right that the heater/AC unit offered by Little Guy is actually a Pet Cool? If so, is there any reason I would pay $595 plus shipping to Little Guy when I can order the Pet Cool for September delivery for $299 shipping included?

http://www.golittleguy.com/cms/options-accessories/options/heating-air-conditioning-2.html
http://www.hitechbuildingsystems.com/HVAC/index.php

Am I missing something? Thanks.

Chuc

[jp03]

Let me throw this into the thinking machine. If you think a small generator is going to run two motors and start them, ur in trouble. The fan will pull about 2 amps, the compressor 4 amps if lucky. They both try to start at the same time! Any induction motor, we have, pulls about 10-20x times the normal amperage power just to start up. It is only for split second, but a generator would have to be big enough to supply it. 6 x 10amps = 60 amps. 60amps x 110 volts= 6600 watts. A average 6000 watt generator might start it. The sudden draw will load up the gernerator, the voltage drop bad, and then the amperage goes up even more. Not to mention the heat damage done to the motors. Motors can only take a 5-10% voltage drop from full voltage design. Best of luck.

[Alphacarina]

Perpetual motion is impossible, cooling 96 cubic feet 30° cooler than the ambient air temperature isn't. Doing it without a noisy generator or a land line may be impossible with current technology, but it wasn't that long ago that the 12v refrigerators (and zillions of other pieces of technology) that are available now were fantasy

True

You need to start thinking in terms of the 12 volt refrigeration you mentioned if you want to pull it off successfully - Doing more with less requires creative thinking

All the therms that actually need 'moving' is the heat from the live bodies contained within the tear plus the heat lost due to the inefficiency of the envelope - The heat gained though the walls, ceiling and floor of your tear

Improve your 'envelope' to about R-30 or so (5 or 6 inches of polyfoam insulation . . . . not too heavy) and then thermopane windows and refrigerator style seals for all openings and you can likely get by with only 1000 BTU's or so of cooling which is much easier to generate than the 3K to 4K most of our inefficient tears require to maintain a comfortable level of cool with two people aboard

Of course, the good 12 volt refrigerators aren't cheap, with their highly efficient insulation and their 'swing technology' refrigeration compressors, but if you're going to rely on something besides a gasoline engine to provide the power, you'll need to improve most every facet of the 'box' you want to cool, plus the technology you use to generate the much smaller amount of cool you actually need . . . . and then hope one of you isn't running a fever

Don

[pbbelly]

How about a follow-up after 17-ish years? We still have our tiny camper. At some point after this thread was playing out, I bought a petcool. I think we only used it on one trip. For the last nine or so years our traveling has been curtailed due to being tied down caring for elderly parents, but we recently have been able to resume travel and in the fall of '23 we pulled it from Central Missouri to far eastern Pennsylvania. A/C was not an issue, so the petcool stayed at home. During the last two weeks of February '24 we took it to Galveston and stayed at a beach campground for about a week. Temps got up in the 80's during the day but nights were very comfortable. The second week was up in Wichita Falls and the weather turned off much cooler, so again A/C wasn't an issue. It's a good thing too, because it never occurred to me to bring the petcool along. I never have tried running it off of an inverter. Battery and inverter technology has improved so that concept might be worth revisiting, but for now I'm content to refrain from humid weather camping.

[ADDvanced]

I haven't had AC but honestly at night I rarely need it. During the day I'm not in the camper. But as long as you have a roof fan extracting air, and a vent/screened window near your face, I am pretty good even in the south west.