Air condition off grid/boondock

Cbusguy

New guy here.  Looking at purchasing a tag in the spring and had some questions

We live in Ohio and plan to use it to fish the east coast from Florida to Maine.    Lots of road travel.   So my question is staying cool while sleeping in rest areas or truck stops during summer heat. No shore power

Setting up a generator seems dicey because of theft concerns and courtesy.

Did the research and battery/inverter are prohibitively expensive not even considering the weight.

Guide me oh travel gurus

Sharon_is_SAM

If you need A/C without a generator you need a campsite with electricity.  I know some of the Ohio turnpike offers overnight RV electric hookups for a fee.  Not sure what other states offer.  Go to Allstays to identify private and public facilities.  There may be some kind of portable cooling apparatus that tents use, but I am not sure of their power needs.  

Sharon_is_SAM

https://www.etsy.com/listing/589364418/12v-portable-air-conditioner-cooler-30?gpla=1&gao=1&&utm_source=google&utm_medium=cpc&utm_campaign=shopping_us_a-electronics_and_accessories-gadgets&utm_custom1=a6841666-07df-4bd5-a6bc-ca174f1294fd&gclid=EAIaIQobChMIj5iil93q3QIVkoZpCh2H7waKEAkYASABEgJanfD_BwE

dhauf

While it may be possible you would only be able to run the AC for a very short time. The AC unit draws about 500W from my measurements.  A group 24 battery is good for about 40AH's when fully charged before drawing it down to the 50% mark.  This may give you about an hour of run time.  You would need a much bigger battery bank and something to charge it.  Or go with more expensive lithium cells and you can draw those down further.  While it is possible, it's not practical nor financially worth it in my opinion.

Cbusguy

A bit of background I am an engineer.   Did the math and looks like I would need 600 amp hours of battery at 12 volts to run it all night. The inverter would require about 60 Amps to create 6 at 120 volts, roughly. Doable with lithium but about $5k for the battery's.   Not worth it

So looking for how you guys stay cool while sleeping

Cbusguy

Then we get into the how do you recharge 600 amp hours, safely  in a day

dhauf

@Cbusguy that is correct, while certainly possible it is just not feasible.  The expensive of such a system would surely cost more that the T@g itself.  Good quality batteries are not cheap, to push 600Ah back to batteries would take a while even at 30 Amp charge rate it would take about 24 hours to charge. 

George101

How far away from the TAB does the generator need to be?

Cbusguy

Sharon_is_SAM you have my answer.  I can build one of those easy and just need to figure out how to duct it into my tag.   There is a fellow that has it all mapped out and it gives an easy 30 degree temperature drop. More than adequete for my needs

Thx for the fresh perspective.  Busy using math when all I needed was a little common sense

Sharon_is_SAM

Welcome.  Check out some reviews.  Not sure how these work in  humid environment.  May work better out west.  Good luck and let us know how it works.  Are you on the TaG forum?

Cbusguy

Actually there is a number of different designs.  Some rely on humidity from direct air flow over the ice .   The unit I am going to build uses a layer of ice separated from the Aire flow compartment using a series of small radiators with ice water pumped through then for cooling.    Cool Air without the humidity problem.

Again thanks for the fresh perspective

Cbusguy

I checked the tag forum not much going on in there

DougH

(deleted too expensive option) 

Cbusguy

Doug it's possible,  absolutely possible and a matter of throwing big stacks of money at it.   Since I am not independant wealthy need to go another route. Going to try the ice cooler air conditioning system.   I have about 75 bucks in parts so far and a beat up Coleman cooler.....

Ratkity

Just remember swamp coolers work when the air is dry. They don't do so well in high humidity.

Cbusguy

Ratkity....I found a version that uses a heat exchanger and a bucket of ice water.    Basically you pump ice water out if the bucket thru the radiator and blow air through the radiator.   In therory no humidity 

And it will be fun to build and test

Ratkity

Cbusguy said:

Ratkity....I found a version that uses a heat exchanger and a bucket of ice water.    Basically you pump ice water out if the bucket thru the radiator and blow air through the radiator.   In therory no humidity 

And it will be fun to build and test

Oh! I saw those plans. Remember to take pictures as you put it together along the way. I really want to see how it goes together and works!!

jkjenn

I have not done it, but others in the FB grouo have used a Goal Zero yeti battery to run the AC for a few hours.

If it is hot and humid, I get a campsite. If it is just hit, I might try the fan, only. It is is u der 60 degrees, and not terribly humid, I will overnight at Walmart and use the fan.

Cbusguy

Not a big fan of those "solar generators".  High dollar marketing hype in my book . Lots of you tubers Hawking them through their Amazon links.

For the amp hours I can buy twice the battery capacity and run it thru an inverter I already own for the same money.

Looking forward to tinkering with the electrical as well.  At one point considered running all power from AC to DC back to ac.   We will see once I get it in the feild a time or two

BirdieJane

Here is a 24 volt $1,500.00 option without the cost of battery. http://www.indelb.com/products/truck_air_conditioning/sleeping_well/sw_cube
for your power needs https://www.wattfuelcell.com/ now all you need as others have said is the cash.

Cbusguy

Looked at the watt fuel cell and it is a long way from being available to the DIY community and it has a zero install base.   I investigated fuel cells and the best one going is the German made efoy, but even new their biggest consumer model only produces 8 amps at 12 volt DC  and uses methanol and cost $5k

The watt propane cell's performance curve shows a only 70 percent performance at 4000 hours of use.  And the potential cost is in the $5k-9k range.  I don't care to be on the company's experimental install base.

 Someone on one the engineering forums I read mentioned/was concerned about impurities in the propane and how they will be removed and hownthey will impact the membrane.    Efoy deals with it by selling you methanol. And it is expensive $7 per kw of power generated.    I pay 7 cents per kw at home.

It is interesting techology for sure.   I hope they continue to develop it.

I looked at the DC air conditioner units.    The model in the link requires a 950 watt power supply which is 80 amps DC at 12 volts.   Looking at worst case that would take 640 amp hours at 12 volts for 8 hours of sleep. At 24 volts should be 320 amp hours.


Traditional ac  without a generator off grid is doable.   Just not practical for most of us

Cbusguy

@ratkity I received most of the parts for my cooler ice water air conditioner system.    It uses a bilge blower out if a boat and a bilge pump to circulate water.   Inital test look at 5-10 Amps for the setup.  The big change I am toying with is mounting the heat exchangers in the camper or just outside and pumping the water to them and back.   This would minimize air heating during transit to the camper

Tabnero

here is a 12 volt ac looking to make its way to the market
https://www.indiegogo.com/projects/in-outdoor-solar-powered-portable-air-conditioner#/

dhauf

@Cbusguy this is the only unit I've ever seen that runs off a battery and has an actual compressor: https://www.zerobreeze.com/products/zero-breeze-portable-air-conditioner I have seen so many videos and project showing the underwhelming performance from the DIY cooler box designs.  You need a way to exhaust the hot air out.  If all your doing is recirculating the air it will never work properly.  These little trailers can get pretty darn hot in the summer time, I just don't see it working well, but worth the experiment.  Who knows I may be wrong.  Even the Zerobreeze device is not cheap and only gives you 5 hours of cooling time.  Not sure how well they work either since I've never used one.  Let us know how the project goes, will be interesting to see how your design works out.

Cbusguy

@dhauf I am talking t@g not t@b.   Leaving the roof vent open at the minimum makes sense as the cool air will displace the hot air out the top of the camper. 

My reason for pursuing this is boondocking while traveling.    I need/want ac for better sleep at truck stops rest areas or parking lots.   I do not intend to use a generator theft and fuel concerns.  I plan to get truck fuel and ice before I camp for the night.

  I am not sure of the exact interior volume of the tag but it can't be much more than 150 cubic feet.   Seems possible

Keep in mind the design idea isn't the swamp cooler idea that most of those cooler air conditioners work on....but uses radiators for the heat exchanger.  The radiators should pull the moisture our if the air as it cools it.    Building it and testing it is the only way to know for sure

Seems very doable to me.   

Cbusguy

@dhauf looked at your your link.   The only concern I have is where the condensation goes.   It is a definite possibility with only a 12 amp draw.  8 hours sleep is only 96 amp hours per night.   Definitely possible

dhauf

@Cbusguy yeah kind of a neat idea on the zero breeze but agreed, I don't know anything about it either.  Will definitely be interested in your design in the T@g for the cooler.  Keep us updated as you build it, definitely a cool idea.

Cbusguy

I could see pulling out the exsisting AC powered AC unit and trying that zero breeze unit.   I think the 1200 BTUs should be enough to cool a t@g then you could use the exisiting drain pan .

90 amp hours on solar is kind of a big number for a portable system.

jkjenn

Not sure how much you have looked into it, but boondocking sites, outside of WV, but it is hard to find many boondocking sites east of the Mississippi. Some state forest sites, national forest, and bureau of reclamation type sites, but not a ton. Also, if boondocking hous should not be an issue as you are usually pretty far from anyone else. Did you mean dry camping?

The other thing to bear in mind, is that you usually still need to unhook your trailer to make sure that the A/C drains the correct way and does bot leak condensation back into the trailer.

This is why I prefer going west and prefer going in the fall. Overnighting in  a Walmart parking lot vs. getting a site, in looking and plugging in so I can run the A/C.

Cbusguy

@dhauf there are a number of you tube reviews on it.   The folks doing the reviews did a less than stellar job.  I was left......I guess baffled is the best word.   Not sure what to think of it

 And at nearly $1k it is too expensive to just try especially since it is directly drop shipped from China.  Warranty service or a refund seem like an impossibility.

Sprockethead

I've done calculations to run A/C off batteries, the biggest problem is how to recharge them. It's simply unsustainable... My plan is to deal with the heat by using fans. In an "emergency" situation(I can't sleep for several nights), I plan to run my truck with an inverter hooked up for a couple hours to cool down. The only other way in my opinion is a small Generator. Perhaps someone has tried a Honda 1000 watt?