DIY Solar Swamp Cooler

Q1: What voltage and amp blower FAN and WATER pump motors are you using?

Q2: Single or multiple speed blower FAN?

Q3: DAYLIGHT only or 24 Hr operation?

Q4: What are the solar panel's VOLTAGE and AMPERAGE output ratings at nominal solar irradiation (~1000 W/m²)?

This Application Note 9, although for sizing solar panel and battery for a home weather station, should steer you toward a reasonable answer:

https://www.davisinstruments.com/product_documents/weather/app_notes/93004_309-AN_09-solar-panel-power.pdf

4 panels at 200 watts each = 800 watts divided by 12 volts = 67 amps

Seems like you have way more panels than you need....or there's something you're not telling us...

If your motors are 12 volts, then the panels must be connected in parallel...In any case the system will be running off the batteries and the batteries will be charged by the solar panels...so you need a charge controller...

If you're drawing 5 watts per hour and you want the cooler to run 8 hrs, you will need 45 amp hours, then you need to add for the fan, what is the fan wattage? ...So you need to know the battery amp hour ratings...

Here's a solar powered pump setup...click on pic

https://www.hunker.com/12447711/how-to-convert-a-swamp-cooler-to-solar-powered

The first thing you need to determine is the amount of space you want to cool....then you can determine airflow necessary, then you can calculate evaporation rate, which will then determine the water gpm requirement...this will then give your power requirement, which will determine what size panels you need and battery storage required for running the system which is determined by the reliability desired....

https://www.air-n-water.com/evaporative-cooler-size.htm

Be a lot easier to just make a misting fan....

The instructions for the controller, the box between the battery and the solar cells, will tell you the voltage it is rated to take from the cells. The solar cell voltage will be higher than the battery voltage, typically, a 12 volt battery is common, but two 12 volt batteries might be combined to drive a 24Vdc fan motor, for instance. (likely 12 Vdc fan though, as for RV usage).

With 3 cells, more likely to be connected in parallel, to get the desired power output. Amorphous cells are not as efficient as other types, so you need more to get the same output.

For the "kit" you have, some numbers (to the limited extent they have been described) don't seem to match up very well. Try to give more info about fan power requirement (pump power should be minor in comparison).

In your situation, you might not need batteries at all, much less a charge controller. Instead, you might consider a "let 'er rip" system with just solar cell(s) supplying the two motors. When insolation is low, you won't need much cooling, so decreased voltage might not be a problem.

The pump and the fan are 12 volts. Everything is based on 12 volts. By "let 'er rip" do you mean to bypass the batteries all together? That would eliminate the need for the charge controller wouldn't it?

yes, you wouldn't need a charge controller, except the voltage supplied by the panels might not be correct for the motor. Also, you should be able to run just about everything in the trailer with this setup, without running a generator, day or night, with your 3 batteries (no a-c unit). The charge controller primarily makes sure you don't over charge the batteries, otherwise you might be able to dispense with that. A nominal 12 volt solar cell will deliver 18 volts at peak solar input, the open circuit voltage is 22 volts, for example. Your RV lights, water pump, heater fan, hot water heater controls might not appreciate the higher voltage, most automotive alternators top out at about 16 volts.

These only work in DRY climates.

How to Use a Swamp Cooler : 9 Steps (with Pictures) - wikiHow

Yep, the Mojave Desert is a dry climate. Also a very hot dry desert.

You need two of these...about 60 watts each for power requirement and about 3 gallons of water each per day....so only need one solar panel and 1 or 2 batteries...of course you should have some excess power for lighting and other amenities, so the power supply(ie: batteries and solar panels) can be as many as you need...for water, pc, wifi, audio, video and other stuff...

https://www.rvupgradestore.com/RV-Evaporative-Air-Swamp-Cooler-p/2b-0001.htm

That is exactly what I need and it costs half as much as I've spent on this DIY kit. I have a big decision now. Do I put what I already have aside and spend more money on the TurboKOOL or proceed with my original plan? Gonna have to think this over. Either way I am grateful for the information you've sent me.

I would return what I don't need for a refund....you might have a restocking charge or shipping costs associated, but here is where you find out how honorable the company you bought from is....or you can always sell stuff you don't need ....in any case cut your losses, and recover what you can...

I live in Mesa, AZ so I know how hot it gets.

Just keep at it and seek help from solar forums and other DIY sources.

Maybe try Instructables.

Good luck!

Thank you for the encouragement. I believe it actually gets hotter in Arizona, doesn't it?

Do a search on "Instructables.com" for information to help you, it's a do it yourself site.

Mary,

good idea for using an evaporative cooler to help keep the temps down in your RV.

Now I won't lie to you and tell you that evaporation cooling is better than freon based cooling systems, it is that they are cheaper to run, repair and service . I checked online to see what things cost, DIY or ready made. A friend of mine has a fifth wheel RV that he wanted to install an evaporative cooler in. Since your going to be doing all of the labor, you can cut out the middle man ( me ). 4 - 200 watt pv panels @ 150.00 =$600, 1 - 1200 watt inverter $200.00, 1 - deep cycle marine battery $200.00, controller, switch's, wiring, etc, $100.00, ~ $1200.00 . With a DIY, you try to save money where you can.

The Turbo Cool, is not a bad little unit, it's just that it's a little unit, figure by the time you buy it & all of the other " extra " parts needed to set it up, well, there is your $1200.00 dollars. I try not to make a habit of criticizing somebody else's images, but if you look closely, you can see an image of an turbo cool and and image of an RV, sans a turbo cool installed ( I think you know what an RV looks like ). Getting back to the T/C, it takes a 14" roof opening and its fan pushes about as much air as a typical bath room vent fan ( which ain't nothing to write home about ) , then you get to use your spare 14" ceiling-roof opening ( don't got one ? , unless you got the tools, you need to call me to help sort things out - we wouldn't want to compromise the integrity of your roof now, would we ? ) . Remember, this is not an a/c unit. A standard air conditioning can push air from the center of a room and can more or less cool the circumference of that room, all things being equal. An evaporative cooler needs to push air from one side of a room to the opposite side of the room. An RV is like a long tube ( kitchen > bath > living room > bedroom ) , so by moving air along the long axis of the unit is more efficient overall. I could go into other details and claims by this manufacturer but that would take more time, besides its breakfast time and my coffee is getting cold.

The unit pictured and linked is 750cfm, your typical bath exhaust is 50-75cfm.... and I said she needed two units...14" holes are standard....she doesn't need a $1200. inverter, it's all 12v...

Oh, I'm sorry, I should have said x 2 or $2400.

Then a DIY is cheaper.

Yes, 14" is a standard , now all she has to do is cut 2 holes.

Three issues I see here are : a. Can the roof ( by itself ) support a 250 lb man/woman service technician. b. The archimedes screw pump. c. Filtration pad area.

If the travel trailer is indeed *parked* and not movable (for now), why not simply buy a single SMALL window-installation evaporative cooler to blow air thru the trailer from one end to the other; operates on normal 120VAC power.

That's an idea !

Actually I did the same thing for my friends RV.

I pulled from the trash ( kinda like that Queen guy ) a 1st generation bon air Durango. Modified the housing and electrical, mounted it on a 2x4 home built stand, ducted with 4 feet of 25" flex duct. Approximately $50.00 material cost. Plugged into 120v.

That is what my plans are for, a window installed evaporative cooler. It will be solar powered. The blower is pulled out and replaced by a 12v radiator fan and a 12 volt water pump (brushless). A 5 gallon water bucket is placed on top and gravity fed into the float. I have the option of using two 5 gallon buckets, the second one up higher than the first.

Mary, I don't know about the 2 bucket idea,,,,especially putting them on the roof. A. You have to climb a ladder to refill the bucket (s). B. Cooler water will absorb more of the energy from the heat load, putting water storage on the roof will counteract that.

How about this idea : you've seen those automatic pet water bowls ? Using hydrostatic pressure is a lot easier on the knees than climbing a ladder.

You can use your solar cells & batteries to run your house water pump, fill up the buckets on a schedule, once you have some running experience. You have a well or water hookup but no electricity(?)