Running 5000 BTU air conditioner solar

[J.P.M.]

Running anything substantial off grid is not cheap. The batteries, surge capable inverter, and
much larger solar array with supports and controller are not cheap, and much larger, to deal
with the gross inefficiency of the extra components. Baby sitting a battery bank for a lifetime
with regular replacements is not something I would care to take on. Bruce Roe

OP: As those who have done it without the benefit of experience have learned - usually it seems more often than not the hard way, off grid lifestyles are expensive in terms of $$ costs and lifestyle adjustments. Living on an acre with no utilities to it will put you in a box. Either spend more than your ignorance led you to believe or adjust your lifestyle and expectations, or some mix of the two.

[J.P.M.]

When I entered Mitsubishi ACDC12C in my internet search, it came right up. It claims an AC line SEER
of 22, already way better than the crowd. If I put in a link, it will get caught in moderation. Also on Utube.

They say it will run on 3 panels in the 300W class, I think around 110VDC. It runs better on 6 panels. I
do not know your particulars but you can look it up and decide. Bruce Roe

For those not in the know, I'd suggest being careful about comparing A/C or heat pumps on the basis of something called "SEER" alone. Big SEER's are inviting but can be deceptive. That "SEER" is a slippery concept and number because it's based on "seasonal" conditions. One question is : Whose season ? A second question is : Whose use pattern ? Notice that the more quantifiable "EER" for the ACDC12C is a more realistic and thermodynamically defensible 12.5 = (COP of 3.7)*(3.412 BTU/Wh).

Since any standards for calculating that number ("SEER"), such as they may exist, seem to be, by necessity/definition, loosely defined and by choice it seems more loosely enforced, if at all, and also, as an example, since "seasonal" efficiency in a cold climate will be different from "seasonal" efficiency in a warm climate, and in any case more a f(location climate) than a hard number, I'd ignore the "SEER" B.S. altogether and go by "EER" as a comparison.

To my opinion only, that SEER crap was conjured up by marketers as little more than yet another way to muddy the waters and separate folks from their money.

Better yet is to go by the COP of a device which is the ratio of the energy sought in either cooling (refrigeration), or heating (a heat pump) to the energy that's input to achieve the desired result.

While "SEER" may fit that definition in the sense that my needs may be met with more or less energy input than someone else's needs, the less than precise way the term "SEER" is defined makes it useless for much of anything beyond deception. I might get an SEER of, say, 30 out of a device because of my climate and use pattern. Some other user, even in the same climate, may not be able to do much better than a 15 or so.

Use the COP for comparison when acquiring, and use the device wisely. Forget the "SEER" crap.

[bcroe]

Okay I found it. Really nice unit I like how you can hook the solar straight to it without batteries. Problem is it's $1,800! I'm going to be on a tight budget . And I can probably run the 5000 BTU window unit on the same amount of panels and it's only $125.

Running anything substantial off grid is not cheap. The batteries, surge capable inverter, and
much larger solar array with supports and controller are not cheap, and much larger, to deal
with the gross inefficiency of the extra components. Baby sitting a battery bank for a lifetime
with regular replacements is not something I would care to take on. Bruce Roe

[Keith Mo 200]

When I entered Mitsubishi ACDC12C in my internet search, it came right up. It claims an AC line SEER
of 22, already way better than the crowd. If I put in a link, it will get caught in moderation. Also on Utube.

They say it will run on 3 panels in the 300W class, I think around 110VDC. It runs better on 6 panels. I
do not know your particulars but you can look it up and decide. Bruce Roe

Okay I found it. Really nice unit I like how you can hook the solar straight to it without batteries. Problem is it's $1,800! I'm going to be on a tight budget . And I can probably run the 5000 BTU window unit on the same amount of panels and it's only $125.

[Bala]

I just saw the show on Discovery Channel building Off the Grid. This guy dug big Trench around his place set up ducting in the trench and had air being sucked out through the floor pumped through the tubing in the cold ground back into his place for AC. I wonder how cold it actually is.? Would this work in Florida?

I live in the tropics so the ground is not cold but there is a deep creek behind the house and the air is cooler down the bottom of the creek, I did think about putting in a pipe and fan to draw the cool air up.

But being off grid generally means you are a power saver/miser or very rich, so the gain from what little cool air I would get was not worth the sacrifice of power.

I have seen and read about quite a few off grid homes, they are portrayed as being the best thing since sliced bread, but you dont very often see follow ups in 5 years to see if their batteries are still ok, or how much generator run time they need to live the life they want to.

My house is just as unbearable during the night when it is monsoon season so having an A/C unit that only runs during the day is not worth my while.

I suppose what Im trying to say is do a lot of research and consider all factors, not just sales hype and what you want to hear.

[J.P.M.]

I just saw the show on Discovery Channel building Off the Grid. This guy dug big Trench around his place set up ducting in the trench and had air being sucked out through the floor pumped through the tubing in the cold ground back into his place for AC. I wonder how cold it actually is.? Would this work in Florida?

Depends on a lot of factors, primarily on ground temp. and soil characteristics. Usually a poor idea for a lot of reasons. Not too many HVAC engineers use such methods for their own homes. Does that tell you anything ? It won't work well in most any location unless carefully designed and probably for larger than household applications.

[bcroe]

Bcro thanks for the suggestion. I could not find that model you listed. How much energy do they use? I see Seer ratings but I don't know how that translates to amps or Watts?

When I entered Mitsubishi ACDC12C in my internet search, it came right up. It claims an AC line SEER
of 22, already way better than the crowd. If I put in a link, it will get caught in moderation. Also on Utube.

They say it will run on 3 panels in the 300W class, I think around 110VDC. It runs better on 6 panels. I
do not know your particulars but you can look it up and decide. Bruce Roe

[Keith Mo 200]

I just saw the show on Discovery Channel building Off the Grid. This guy dug big Trench around his place set up ducting in the trench and had air being sucked out through the floor pumped through the tubing in the cold ground back into his place for AC. I wonder how cold it actually is.? Would this work in Florida?

[Keith Mo 200]

Bcro thanks for the suggestion. I could not find that model you listed. How much energy do they use? I see Seer ratings but I don't know how that translates to amps or Watts?

[bcroe]

Let me suggest something else. Forget your highly inefficient window shaker, which wants you to convert
DC to battery to AC. There are now mini split HEAT PUMPS (Mitsubishi, model ACDC12C) that are FAR
more efficient and will run DIRECTLY off your solar panels. They won't run without good sun, but then
you don't need air. Can do some heating too. Bruce Roe

[Keith Mo 200]

Keith Mo:

You seem to among the myriad who show up here, more than a few after the damage has been done, who jump on a germ of an idea planted by some peddler or the green wash media without knowing what's involved, either from the standpoint of what's required, what's available, what all of it will cost and how practical or impractical it may be.

Stay on the grid until you've fully researched the idea. You'll learn as much, if not more about what's needed for a lot less toil, treasure and wasted effort. Experiment is fun and makes a nice hobby, but don't expect what you have in mind to be in any sense practical.

Thank you for the advice .
I have an acre in Northern Florida. I've always plan to eventually move there . There is no grid to tie two. Other big problem is there water either. Wells are expensive 2. So that's exactly what I'm doing fully researching trying to learn as much as I can and knowing what is actually possible for practical and what is not. Especially with a low budget. Yes it is fun I have made a 75 watt panel soldering each cell together. Was a fun project.

[Keith Mo 200]

Sunking. I understand this. Why so aggressive and negative. It's like you want me to fail. I never claimed to know what I'm talking about that's why I'm here to learn. I realize now what it takes to run something like even a tiny 5000 BTU isn't feasible. One big thing I learned from you is amp change from 120 volt and 12 volt. Don't know how I missed that just learning so much so quickly some things are bound to go in one ear and out the other. The 75 watt panel that I have I actually made myself soldered each cell together encapsulated it with film and heat gun. Was a fun project.

jflorey thanks again for the positive feedback and actually trying to give me an option of what is possible.

[Sunking]

"If you absolutely must use batteries, get a big solar array (1000 watts or so) a smallish 12V AGM battery and a 2000 watt inverter. Then only turn on the A/C when the sun is shining."

jflorey thanks for the idea. Will this destroy the battery from running such a big load off of it? Can I still get the full life expectancy?
[/QUOTE]First partly cloudy day and you are toast.

[J.P.M.]

Keith Mo:

You seem to among the myriad who show up here, more than a few after the damage has been done, who jump on a germ of an idea planted by some peddler or the green wash media without knowing what's involved, either from the standpoint of what's required, what's available, what all of it will cost and how practical or impractical it may be.

Stay on the grid until you've fully researched the idea. You'll learn as much, if not more about what's needed for a lot less toil, treasure and wasted effort. Experiment is fun and makes a nice hobby, but don't expect what you have in mind to be in any sense practical.

[jflorey2]

jflorey thanks for the idea. Will this destroy the battery from running such a big load off of it? Can I still get the full life expectancy?

It will definitely shorten the life of the battery, but you're not using the battery for energy storage, so it doesn't matter as much. You are just using it to store enough energy to start the compressor. All the run power comes from the solar array.

AGM's can charge/discharge at around C/4. So you do the math. 1000 watts gives you 83 amps at 12V, so you'd need (83*4)= 330 amp-hours. Two DC400-6's would work.