Running a small 5,000 BTU 115V Window Air Conditioning Unit

[J.P.M.]

But, everybody's doing it. look see..

Not everyone, but maybe a lot of those who feel justified suspending the need for critical observation/thinking and so only see what they want to see.

[Logan5]

If the 5,000 BTU A/C unit is run @ 77 F, the unit may work only like 1/4 of its full capacity, so it will cut your calculations to 1/4. @ 77 F there will be no humidity, no sweating, I can sleep very comfortable. Also, there are many things one can do to make the A/C unit to keep the room cool like sealing every hole in the room, install reflective paper on the windows, put some fans in the room to circulate the cool air, etc.

Once the room is cool, the A/C units just has to keep it at that temperature with not much effort.

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

But, everybody's doing it. look see..

[J.P.M.]

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

U-tube == The new idiot's bible.

[LETitROLL]

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

That is one of the funniest things i have ever seen my whole life, those "meaningless calculations" are physics, a measurable, precise, unchangeable force of this universe. If you are only looking to "play" and experiment around with temporary, short, lived, patched together systems, that will need components replaced or upgraded often (Expensive), or only to cool a small amount on certain days, then lots of things will work.The answers you have gotten here with the "meaningless calculations" in them are for real world, properly working, long term working without too much trouble systems, that can cool well in varying conditions. Lots of things can be done, what you are looking to do can be easily done, but math makes is certain that you will either spend a lot of Money, or not get much cooling over the long haul, you can get a lot of cooling for a short time, and then buy a new inverter, or more batteries, or you can use "meaningless calculations" to properly design a system that does not nickel and dime you to the poor house. Math dictates how each system will work, not tricks, or luck, so in the end every system will succeed or fail based on the math (even the systems on Youtube). As was mentioned earlier, the only "trick" than can get you more cooling for not too much more money, and still satisfy the math that makes the cold air come out of the vent in the first place, is a mostly daytime system with more panels, and not too much after sundown battery use. Not one person in this universe has ever been able to trick, or defeat math yet, so you can go with it, or learn the hard way (expensive or warm air).

[J.P.M.]

Do you not understand that my calculations showed that your proposed "PV + Battery Bank + A/C" system will work?
So, why the hostility towards real math?
Do you understand the math or not?
You must calculate (know), at a minimum, three parameters for your project ...
1) How many kw-hrs your loads will consume each night
2) How many kw-hrs your pv panels will generate each day
3) How many kw-hrs your batteries can supply before 50% DOD
This requires meaningful calculations!

Without knowing the r-value of the walls, the ceiling and the floor and the temperature differential,
it is extremely difficult to state, as fact, whether the A/C will run at a low 25% Duty Cycle or not.
That is for you to decide, and you can apply that MATH to your project.
No thanks - I will not "blindly trust" any you-tube video.
I prefer to do my own math calculations, that way I know my calculations are appropriate for my project.

+1. Start with knowing what you're up against and see what (mental) tools you need. Then fill in the knowledge gaps. All the OP needs here is to keep the horse before the cart, learn what's needed in order to understand what's happening, and then match what's available to meet the as yet undefined load/goal. Doing so may lead to a project that initially involves more learning than doing, and then sealing/insulating, and measuring/estimating/defining a load. While doing that, the OP may perhaps discover that, at least in its current state of development, PV is mostly not as cost effective or practical r as much of a cake walk for small, off grid applications as the solar peddlers and their tree hugging shills would want the solar ignorant to believe. Knowledge is power.

[NEOH]

If the 5,000 BTU A/C unit is run @ 77 F, the unit may work only like 1/4 of its full capacity, so it will cut your calculations to 1/4. @ 77 F there will be no humidity, no sweating, I can sleep very comfortable. Also, there are many things one can do to make the A/C unit to keep the room cool like sealing every hole in the room, install reflective paper on the windows, put some fans in the room to circulate the cool air, etc.

Once the room is cool, the A/C units just has to keep it at that temperature with not much effort.

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

Do you not understand that my calculations showed that your proposed "PV + Battery Bank + A/C" system will work?
So, why the hostility towards real math?
Do you understand the math or not?
You must calculate (know), at a minimum, three parameters for your project ...
1) How many kw-hrs your loads will consume each night
2) How many kw-hrs your pv panels will generate each day
3) How many kw-hrs your batteries can supply before 50% DOD
This requires meaningful calculations!

Without knowing the r-value of the walls, the ceiling and the floor and the temperature differential,
it is extremely difficult to state, as fact, whether the A/C will run at a low 25% Duty Cycle or not.
That is for you to decide, and you can apply that MATH to your project.
No thanks - I will not "blindly trust" any you-tube video.
I prefer to do my own math calculations, that way I know my calculations are appropriate for my project.

[inetdog]

Just choose between parking the RV is full sun to get maximum power to run the A/C or parking in the shade and not needing as much.
A lot to be said for detachable ground mount panels.

[john95]

Will the compressor in the Window A/C run 100% of the time?
What if it operates at 50% duty cycle?
I found a GE 5,000BTU that uses 3.6 amps (running)

115 volts x 3.6 amps x 6 hours x 50% duty cycle = 1,242 Watt-Hours consumed per night from batteries
6 hours (sun equiv) x 5 panels x 320 watts = 9,600 watt-hours generated each sunny day
8 batteries x 6 volts x 225 ah x 50% DOD = 5,400 watt-hours usable

How many hours of unobstructed sun does your location get daily?
How many consecutive cloudy days?
How deep do you want to discharge the battery bank? 50% MAX?

The battery bank will easily run the A/C for one night.
And the PV will easily replace the 1,242 Watts-Hours consumed, the next afternoon.

Now, what if you have 4 consecutive days of no sun?
The battery bank will run the A/C for 4 nights with absolutely no solar power input.
It might take two consecutive sunny days to recharge from 50% DOD up to 100% SOC.

Periodically verify all 8 batteries are well balanced in those 4 parallel banks.

If the 5,000 BTU A/C unit is run @ 77 F, the unit may work only like 1/4 of its full capacity, so it will cut your calculations to 1/4. @ 77 F there will be no humidity, no sweating, I can sleep very comfortable. Also, there are many things one can do to make the A/C unit to keep the room cool like sealing every hole in the room, install reflective paper on the windows, put some fans in the room to circulate the cool air, etc.

Once the room is cool, the A/C units just has to keep it at that temperature with not much effort.

Check on youtube all the videos where people demonstrate a 5,000 BTU and 6,000 BTU A/C units working fine on a RV or small cabins. Just search for "5,000 BTU air conditioning running on solar". This is the real thing, not meaningless calculations!

[LETitROLL]

Since summer is around the corner I thought I'd work on a solar project to cool me down with sun power just for fun.
I was planing on these components:

4x Trojan T105 6V batteries as a 24V array
2x Mission 320 Watt 24 Volt Monocrystalline
HQST 40A MPPT Solar Charge Controller
Go Power 600 Watts 24V Pure shine inverter
Usage will be only 6 hrs daily.

Do you think that this is doable? Thanks.

A/C is not Cheap, or easy to run from basic solar, Large, expensive, solar setup = no problem. Solar panel prices are coming down tremendously in most locations, i also see brand new 280 to 310w panels in my area for about .50 cents per watt., with that in mind the only way to "cut corners" and play with a fun cool down project for a fair cost is to oversize the panel array (they are cheap now and last a long time), then mostly only run the system during sunny daylight hours, if cloudy it is usually not as hot so you would not need to run system much, and a modest battery bank will allow you to run it for an hour or 2 in the evening after sundown. The batteries in any off grid system are by far the biggest loser (on a grand scale), solar energy by nature comes from the sun, that technology is getting better and cheaper all the time, trying to store the energy and use it later, well that is a giant inefficient process that is not really getting much better, or cheaper, so go with the sun and stay away from the storage in your design and you can do quite a bit without breaking the bank. Most high quality controllers allow current limiting so you can prevent your larger array from hitting your modest battery bank with too much current.

[NEOH]

Thanks for the components and capacities suggested. I just feel the price of these components is a little bit high.

For the panels alone, to make up the 1,600 watts requirement, I can pick up 5x 320 watts 24 Volts for like $720.
for the the batteries, I can get me 8x used 6 volt 225 Ah for like $200
80 Amp MPT Outback Flexmax for like $500
AIMS Power 2000 watts 24v $600

Total Cost= $2,020.00

Also, I'm thinking on building my own air conditioning unit that would spend no more than 70 watts @12V. 500 watts it is way too much.

Will the compressor in the Window A/C run 100% of the time?
What if it operates at 50% duty cycle?
I found a GE 5,000BTU that uses 3.6 amps (running)

115 volts x 3.6 amps x 6 hours x 50% duty cycle = 1,242 Watt-Hours consumed per night from batteries
6 hours (sun equiv) x 5 panels x 320 watts = 9,600 watt-hours generated each sunny day
8 batteries x 6 volts x 225 ah x 50% DOD = 5,400 watt-hours usable

How many hours of unobstructed sun does your location get daily?
How many consecutive cloudy days?
How deep do you want to discharge the battery bank? 50% MAX?

The battery bank will easily run the A/C for one night.
And the PV will easily replace the 1,242 Watts-Hours consumed, the next afternoon.

Now, what if you have 4 consecutive days of no sun?
The battery bank will run the A/C for 4 nights with absolutely no solar power input.
It might take two consecutive sunny days to recharge from 50% DOD up to 100% SOC.

Periodically verify all 8 batteries are well balanced in those 4 parallel banks.

[J.P.M.]

Also, I'm thinking on building my own air conditioning unit that would spend no more than 70 watts @12V. 500 watts it is way too much.

How would you go about building your own A/C unit ? Just curious. 70 Watt input might give you ~ 200-300Watts cooling for a reasonably efficient DIY. Any idea what cooling load you're designing for ? Always good to start with a reasonably defined set of design criteria.

[SunEagle]

Thanks for the components and capacities suggested. I just feel the price of these components is a little bit high.

For the panels alone, to make up the 1,600 watts requirement, I can pick up 5x 320 watts 24 Volts for like $720.
for the the batteries, I can get me 8x used 6 volt 225 Ah for like $200
80 Amp MPT Outback Flexmax for like $500
AIMS Power 2000 watts 24v $600

Total Cost= $2,020.00

Also, I'm thinking on building my own air conditioning unit that would spend no more than 70 watts @12V. 500 watts it is way too much.

Great price on the panels but I would be very cautious with the used batteries. Not knowing their true condition may end up costing you a lot more when one or more fail.

[Sunking]

Thanks for the components and capacities suggested. I just feel the price of these components is a little bit high.

For the panels alone, to make up the 1,600 watts requirement, I can pick up 5x 320 watts 24 Volts for like $720.
for the the batteries, I can get me 8x used 6 volt 225 Ah for like $200
80 Amp MPT Outback Flexmax for like $500
AIMS Power 2000 watts 24v $600

Total Cost= $2,020.00

Also, I'm thinking on building my own air conditioning unit that would spend no more than 70 watts @12V. 500 watts it is way too much.

1. Cannot use a Prime number of panels.
2. Used batteries will not last one season, and using Trojan Golf Cart batteries is not the right battery for the application.

[john95]

Absolutely doable, Go For It.

Here is exactly what it will take, nothing less. You have a 5000 BTU Window Shaker that requires roughly 500 to 600 watts of power x 6 hours = 3000 to 3600 watt hours per day to run.

Panel Wattage = 1600 Watts. $3200
65 Amp MPT Charge Controller. $500
24 Volt 625 AH battery that weighs 900 pounds and cost $2200 every few years. That would b 8 of those Trojan Batteries.
24 Volt 2000 Watt TSW Inverter. $650
Misc Materials $400
Total Cost Est = $7000

Absolutely doable.

Thanks for the components and capacities suggested. I just feel the price of these components is a little bit high.

For the panels alone, to make up the 1,600 watts requirement, I can pick up 5x 320 watts 24 Volts for like $720.
for the the batteries, I can get me 8x used 6 volt 225 Ah for like $200
80 Amp MPT Outback Flexmax for like $500
AIMS Power 2000 watts 24v $600

Total Cost= $2,020.00

Also, I'm thinking on building my own air conditioning unit that would spend no more than 70 watts @12V. 500 watts it is way too much.

[Sunking]

Since summer is around the corner I thought I'd work on a solar project to cool me down with sun power just for fun.
I was planing on these components:

4x Trojan T105 6V batteries as a 24V array
2x Mission 320 Watt 24 Volt Monocrystalline
HQST 40A MPPT Solar Charge Controller
Go Power 600 Watts 24V Pure shine inverter
Usage will be only 6 hrs daily.

Do you think that this is doable? Thanks.

Absolutely doable, Go For It.

Here is exactly what it will take, nothing less. You have a 5000 BTU Window Shaker that requires roughly 500 to 600 watts of power x 6 hours = 3000 to 3600 watt hours per day to run.

Panel Wattage = 1600 Watts. $3200
65 Amp MPT Charge Controller. $500
24 Volt 625 AH battery that weighs 900 pounds and cost $2200 every few years. That would b 8 of those Trojan Batteries.
24 Volt 2000 Watt TSW Inverter. $650
Misc Materials $400
Total Cost Est = $7000

Absolutely doable.