Solar setup needed to run RV AC 13,500BTU

[ronm69]

I am just getting started with this solar stuff and now have a chance to set it up on my new 27' TT with a 13,500 BTU AC unit. I want to be able to run my AC whenever I want along with everything else off grid. I am just one guy with my dog that will be living full time in my RV. I am looking at the all-in-one system you show on your site (24v MPPSolar unit). I will also have the EasyStart installed on the AC to lower the startup load typically needed.

So, how many watts of solar panels (I see you mention poly as your favorite) and amp hours of batteries (DIY or Lithium) would be needed (at a minimum) to do this without needing a generator very often to top off the batteries. I currently live in south Florida and expect to have plenty of sun. I'm comfortable building the DIY setup if it's cheaper than the All-In-One system. Thanks for your help with this and love your videos.

 

[Craig]

First thing is to determine exactly how much energy in watt or amp hours you need per day. From that you can start calculating storage needs. After that you need to determine hours of sunlight available for charging to see how many panels you need to make up your daily consumption. All your appliances should list their power consumption somewhere. Great project!

 

[ronm69]

Until I pick it up I don't have that info, but I have a ballpark idea of what is required, but after some research I am wondering if the 13,500 btu ac that is standard on my TT is more than it needs. It's 27' with one slide, so while I can't find the exact sq ft, I am guessing around 300 (open floorplan) at most. And recommendations for that size space is around 7000-8000 btu. The smaller unit would require less energy use, but would it now run for longer periods?

 

[bwalendy]

Powering 13.5k btu A/C with solar will be very difficult indeed. You should consider a much smaller unit.

 

[TCgreg]

We run our 11k unit from our 600ah lithium battery and 1080 watts of solar. Conditions dictate for how long. If it's not too hot and the sun is good we can go pretty much all day with the air cycling 50-70% compressor. If we have no sun and a full battery and 100% compressor about 4.5-5 hours. Lot's of variables. Typically when it gets that hot we move to cooler climates. Not much fun sitting in a camper all day listening to a noisy RV air conditioner.

For day to day use you will need enough solar and battery to both run the air and keep the battery topped off. It won't be charging at night so in the morning you will need enough solar to run things and recharge the battery bank. Not sure a 27' rooftop will allow that kind of array.

 

[Getyourbone]

For example, roughly figure your 13,000 btu alone unit will require 1 12v 100ah lithium battery to run(not start) for 1 hour acountlng some amount of effiency factor in conversion and assuming your ac will run just some percentage of that hour.

1 300 watt panel will get you there for every one of those batteries on a good day...and then some but not on a bad day.

24 batteries and 24 panels for 24 hours for the ac unit to put it in a stupid simple way...soo much more to it but...

Now just start making some compromises and those numbers can come down significantly.

And now that I think about it, I think you are looking at even more than that...

 

[RandyP]

Your first solar project is nearly an impossible feet given the roof size, battery weight limits and size/space for them, inverter size. Hope your pockets are really deep. Over 10k$ just for the solar pieces including battery for this system. A small window AC unit is much more efficient than the rooftop RV AC units. Might be able to pull that off with the roof space you have.

 

[bwalendy]

Just as an example: The space that I cool is 6.5' x 12' (78 square feet) that is triple insulated and has no windows. I am running a microprocessor-controlled A/C window unit rated at 5500btu and 11 SEER. It is pulling a little over 360w after initial startup running at the lowest temperature setting of 60 degrees and no eco-mode for the A/C unit turned on until the interior heat load was dissipated. I tested it with a 2kw propane generator with an A/C current clamp meter and a digital thermometer. The small 2kw suitcase generator was running in Eco Mode and the A/C unit was putting out 46-degrees Farenhight to bring the interior to 60 degrees. That means that I should be able to run my Wynter refrigerator, my A/C window unit and still have some battery charge capacity from my (soon to be deployed) 960-watt solar array when in full sun. I plan to deploy about 1.5k of solar eventually. The lithium battery array is 200ah which will grow to 400ah.

 

[Getyourbone]

Provide some more information and see if everyone around here can figure out a system for you that would work!

Need to do an energy audit and figure out exactly what your minimum needs are… To think that you can run ac for 24 hours a day is not likely possible but to think that you can have it on for a few hours very well maybe

Skip the coffee maker and get a French press

Throw away the 2000 W microwave and get a 700 W one

LED lighting

Be happy not being able to blast the tunes quite so loud

It sure can all work but you just have to figure out a few things that you traditionally wouldnt living on the grid and make some compromises that people aren’t accustomed to.

 

[grizzzman]

This can be and is done. The Ausies do it in 120 f temps. But with this said, real money will need to be tossed at the issue. This forum is very Young, with little knowledge when it comes to mobile a/c. Lots of info in ausie forums. Good luck with your project.

 

[RandyP]

Camper Trailer forum email group ?

 

[martin17773]

Off-Grid Optimist has dedicated videos about how he did it. https://www.youtube.com/channel/UCZgK3N4C91PL60C7lzp2RgQ

 

[bwalendy]

This can be and is done. The Ausies do it in 120 f temps. But with this said, real money will need to be tossed at the issue. This forum is very Young, with little knowledge when it comes to mobile a/c. Lots of info in ausie forums. Good luck with your project.

Short on the detail, long on the bluster. The Aussie way?

 

[grizzzman]

Short on the detail, long on the bluster. The Aussie way?

pick your poison But then you need to separate the wheat from the chaff.

 

[bwalendy]

This guy adds nothing of real value. No math, no example just bluster.

 

[RogerD]

Just as an example: The space that I cool is 6.5' x 12' (78 square feet) that is triple insulated and has no windows. I am running a microprocessor-controlled A/C window unit rated at 5500btu and 11 SEER. It is pulling a little over 360w after initial startup running at the lowest temperature setting of 60 degrees and no eco-mode for the A/C unit turned on until the interior heat load was dissipated. I tested it with a 2kw propane generator with an A/C current clamp meter and a digital thermometer. The small 2kw suitcase generator was running in Eco Mode and the A/C unit was putting out 46-degrees Farenhight to bring the interior to 60 degrees. That means that I should be able to run my Wynter refrigerator, my A/C window unit and still have some battery charge capacity from my (soon to be deployed) 960-watt solar array when in full sun. I plan to deploy about 1.5k of solar eventually. The lithium battery array is 200ah which will grow to 400ah.

What is the make / model of the AC unit?

 

[grizzzman]

This the system i would look into. Much more efficient

 

[bwalendy]

It is relatively inexpensive to install solar-powered air conditioning in a small RV.

What is the make / model of the AC unit?

I attached a photo of the a/c units tag. It is Kenmore but I believe is actually a Frigidaire. I believe that I paid about $100 for the unit in 2003. Some background information is necessary. I first installed this air conditioner in my old high top cargo van in 2003. At that time I had no solar at all. I had about 400ah of flooded Trojan batteries and a Honda EU2000i generator and a 12v Xantrex ProSine 2kw inverter/charger. I would use the air conditioner to cool the van for about five hours at a time (what I call silent running mode) and would need to fire up the Honda to recharge the batteries if I still needed A/C which I never really needed to do. Most of the time I would use it to pull the heat load from the van when I wanted to go to sleep. I spend almost all my time outdoors. I would run the generator to recharge the batteries or use shore power. Not the most efficient system ever designed but it worked very well at a relatively small investment at that time. I was very comfortable in the van on days that were up to about 95 Fahrenheit which was the hottest of the hot days in Portland, Oregon during the summer. It was perfectly adequate. I had absolutely no complaints. The A/C would "hang icicles off your chin" or more precisely, would bring the inside temperature down well below 70 and cycle at about 50%. All I can say is that I was absolutely perfectly satisfied.

Now we jump to 2019 and I still run the same A/C unit installed in a much larger van that is much better insulated than the old cargo van. I have maintained the A/C unit well by keeping it cleaned out. I will, most likely, replace it before long but I have other priorities at the moment (such as getting my solar installed). I recently purchased a 2kw DuroMax inverter generator that runs on propane and gas. I never intend to put gas in it; propane is much more practical for long run times. I still have the same Xantrex ProSine 2.0 inverter/charger.

I have tested the air conditioner with an amp clamp meter a few months ago (see pics). It was pulling about 3 amps after start-up plus five minutes or so I figure less than 400w; most likely 360w. The propane generator is a big improvement over the Honda. It seems just as quiet, runs on propane, is easy to hook up an external exhaust system, etc. It is physically larger than the Honda by about 25%. I am about to install almost 1k of solar on the roof of my step-van. The area being cooled is 6.5' x 12' with a 6.2' ceiling and very well insulated. I plan to grow the solar to 1500w. When you look at this the way I have used it and calculate the cost of 1500w of solar with a charge controller the overall costs are very affordable. What is hard to afford are lithium batteries but it seems that they are a must-have if I plan to go full time. I have 200ah of Battleborn now and plan to grow that to 400ah. The 200ah purchase has left me poor for the moment. Would this work well in 120-degree temps? Probably not so much. It all comes down to where and when and how you will be using it. Lots of variables and there are more efficient systems. However, for the relatively small investment, not bad at all. I look forward to your comments.

 

[Supervstech]

This site looks to have an interesting option between minisplit and rv roof unit...

Dometic

We offer smart and reliable products for people who enjoy outdoor activities enabled by a car, recreational vehicle, or boat.

www.dometic.com

 

[Getyourbone]

It is relatively inexpensive to install solar-powered air conditioning in a small RV.
...
I look forward to your comments.

I’m sure it is doable and with a little creativity can be done for less than more but the problem so often is that a person posts and simply says...I want everything at the same time, anytime and possibly all of the time....


Well the free advise to that is “it’s almost impossible without deep pockets...be willing to bend a bit, invest some t8me into figuring out what is really important and provide a bit more info and some help can be offered but until we know the priorities....blah blah blah”