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Topic: Possible to run an airconditioner using many solar panels?

Posted By: paleontol99 on 10/25/09 11:50pm

Is it possible to run and air conditioner off of solar panels?
If so, can anyone give me an estimate how many 80 watt panels it
would take to run, say a 35000 btu air conditioner. Im not versed
at all in watts and volts. Can a good amount of panels run a microwave.
If they cant run off solar panels, is there a way to get an air conditioner or micro to work along with the addition of solar panels.
Thanks, Jeff


Posted By: Artum Snowbird on 10/25/09 11:59pm

They say that one can run a 9000 BTU air conditioner, which would cool a truck camper, off a Honda 2000 watt generator. That is 25 80 watt panels. That is also only one quarter the size that you are thinking of at 35000 BTU.

A microwave is a short term hog of power. It can run off an inverter, but you would need at least four good size batteries to run it for more than just a few minutes. You could reheat a dinner, but I doubt you could cook for 30 minutes.

Look for "the twelve volt side of life" in a google search and read all about it.


Mike and Carole
2007 Snowbird 9'6" Super Slide Sold
2005 16.6 Double Eagle
2000 F350 7.3 SC 4X4
previously 8'10" Snowbird Camper
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Posted By: Corkey05 on 10/26/09 12:13am

12v Side if Life


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FMCA F374292



Posted By: Golden_HVAC on 10/26/09 12:16am

Hi,

If you have a 6 year old air conditioner with a 10 EER rating, and is putting out 35,000 Btu's per hour, it will use about 3,500 watts. So it will require about 10 panels to make 800 watts, and 50 to make 4,000 watts.

You will also need a pair of Trace SW5548 inverter, with 48 volt input and 5,500 watts maximum output. It might give you the correct surge capacity. When hooked up with a Trace dual inverter kit, it will put out synchronized 240 volt power. The surge required to start the air conditioner is going to take most of what that pair of inverters can put out without tripping on a short circuit overload.

If the house is tied to the grid, then the solar panels are only going to put the energy back into the grid that is used by the house. So it will not require a inverter that large.

If this will be a house built away from the grid, then I would recommend some very energy efficient air conditioners, in the 120 volt and 12,000 Btu size range. 3 will get the same job done, with a much smaller inverter, as each compressor starting current will be much less. And chances are that all three will not be running at the same time, yet even if they are, the 5,500 watt inverter has enough capacity to run two of them, and then have the starting surge of the third one without overloading it.

By getting 16 SEER air conditioners, then the wattage goes down by about 40%. If you where to find 20 SEER air conditioner, then it's wattage requirement is 1/2 of a 10 SEER.

Also with ductless units, you will not lose any air or cooling capacity to the attic. They are extremely quiet, and can run at a variable capacity too.

So three modern ductless air conditioners of 12,000 Btu capacity might use 800 watts each, and require 10 panels each. The inverter efficiency would require 2 extras per air conditioner. And if you have batteries involved, then an additional bunch of panels are required to keep the batteries full - if the house is not connected to the power company.

You would be much better off with 120 watt or larger solar panels. 175 is popular on homes not connected to the grid, as they have less wiring connections and less mounts required.

You can google phred tinsheth and find out more about solar panels on his Poop Sheets.

You can contact this company, and they can quote you a price to purchase it all.

SolarOnSale.com

They might recommend another brand or size inverter.

If you want to run a 120 volt air conditioner on a RV, then a 3,000 watt inverter, such as Prosine 3 KW should work. But the surge capacity might still be not enough, and rooftop air conditioners are not that energy efficient. This would have 12 volt input, unless you have a 24 volt system that you plan on connecting to.

Some larger motorhomes have a 24 volt starter, and a dual coach battery system, with a 440 amp hour 24 volt system for the inverter, electric home sized refrigerator, electric stove and a 440 amp hour 12 volt system for just the lights.

Anything CAN be done if you have the budget for it. I prefer to run my 4 KW generator when I run the A/C unit, so I don't have to dedicate the entire solar output to the air conditioner, and then have a excessively large system when not running the air conditioner.

I was reading Home Power Magazine several years ago, and they showed a home with 6 Trace SW 5548 inverters and a really large solar system. Because their house lost power in 1992 for a couple of weeks after a hurricane, they wanted to be able to run the air conditioners, refrigerator, and all the other things that make it comfortable. They had to replace the compressors in the air conditioners with compressors that have a lower start up amperage requirement.

They also had a 40 KW generator and many things that only a millionaire could afford to do.

Good Luck,

Fred.


Posted By: pianotuna on 10/26/09 12:56am

Hi paleontol99,

In theory, yes, with enough solar panels is possible.

However, it is not very practical unless batteries are used for storage. My system is set up so that I can run my roof air conditioner for up to 4.5 hours without going below 50% of my battery storage capacity.

To get details about my system surf here:

Technology

And click on "Solar Boondocking"

RV air conditioners are rarely 35000 btu's. Many are 13500 and some are 15000. Mine is 13500 btu's and draws 960 watts.

I can also run my microwave for several hours if I so wish.

The problem of running devices directly from solar panels is that when a cloud passes by the sun output drops. Usually in an RV solar panels are used to charge batteries--and an inverter is connected to the batteries to run 115 volt devices.

The sticking point is that most RV's do not have enough roof space for huge numbers of panels. If I run my air conditioner for an hour--it takes my solar panels four hours at maximum output to replace the energy that has been drawn from the batteries.

paleontol99 wrote:

Is it possible to run and air conditioner off of solar panels?
If so, can anyone give me an estimate how many 80 watt panels it
would take to run, say a 35000 btu air conditioner. Im not versed
at all in watts and volts. Can a good amount of panels run a microwave.
If they cant run off solar panels, is there a way to get an air conditioner or micro to work along with the addition of solar panels.
Thanks, Jeff



Regards, Don
Full Time in a Kustom Koach Class C 28'5", 256 watts Unisolar, 875 amp hours in two battery banks 12 volt batteries, Magnum 3000 watt PSW inverter.


Posted By: 2oldman on 10/26/09 06:00am

paleontol99 wrote:

how many 80 watt panels it would take to run, say a 35000 btu air conditioner.
About 30.


Posted By: quabillion on 10/27/09 01:16am

I have 20 panels and even I cannot run the air cond with it. I still have to use the generator for that.


I spend every day of my life trying to understand that other people in this world do things differently than I do.



Posted By: 2oldman on 10/26/09 10:02pm

Polishnurse wrote:

Yuma in the BLM lands to the west, he was all solar powered and wind milled up, built on a trailer to pull all this stuff around, batteries in on the platform base covered from the weather
Yep.. saw one like that at the Q a few years ago. On the bed of a converted Class A tractor, 12 panels on 2 tiltable frames, 16 T105s, 3kw PSW inverter. Awesome.


Posted By: Carri-lite5ver on 10/26/09 07:14pm

towing a extra trailer would be a PITA to deal with to charge your rig. BUT with so many double and TRIPLE towing why not. Hook your truck up put a hitch in the rear of the travel trailer with a 7 way plug and pull away.


Posted By: hershey on 10/26/09 05:35pm

The short answer it: NO.


hershey - albuquerque, nm
Someday Finally Got Here
My wife does all the driving - I just get to hold the steering wheel.
Superman was an illegal alien.
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Posted By: Polishnurse on 10/26/09 02:44pm

Saw a fella last winter, down in Yuma in the BLM lands to the west, he was all solar powered and wind milled up, built on a trailer to pull all this stuff around, batteries in on the platform base covered from the weather, but opened to vent used to store the power, one wind generator that folded down on the front one on the rear, and tow racks of panels that tilted to get the most out of the sun. He just plugged in his 30 amp service to the trailer. Pretty cool. Pretty expensive to set up. But that is how he lives. Bill


Posted By: skipnchar on 10/26/09 07:57am

I don't believe it's PRACTICAL with ANY size air conditioner but....if you have enough batteries in a bank that is being CHARGED by a solar pannel you could run one for a short time and then take a very LONG time to recharge the batteries and go again.


2011 F-150 HD Ecoboost 3.5 V6. 2550 payload, 17,100 GCVWR -
2004 F-150 HD (Traded after 80,000 towing miles)
2007 Rockwood 8314SS 34' travel trailer

US Govt survey shows three out of four people make up 75% of the total population



Posted By: david_42 on 10/26/09 08:31am

35,000 BTU is 3-tons. My 2-ton heatpump requires 2800 watts at 220 volts. So, figure about 5200 watts with converter losses, that's 65 80-watt panels. Since panels are rated under idea conditions, double that.


Posted By: smkettner on 10/26/09 08:55am

35000 BTU will require a fixed installation. No RV could carry that much on the roof. Call a commercial solar installer for an estimate and it will be big.


2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
675 watts solar
Send a PM if I missed something


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