Running 5000 BTU air conditioner solar

[Keith Mo 200]

And when do you say small 12-volt AGM ? like a 100 ahour?

[Keith Mo 200]

"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."
[/QUOTE]


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?

[Keith Mo 200]

Thanks guys for sharing the info. Much spend very disappointing. Looks like my only option would be running it when the sun is shining LOL. I can't be shaking money out of my pockets!

[jflorey2]

Hello everyone. I've been doing a lot of research on solar I have a small 75 watt set up now but I'm just a newbie. I'm going to be going off grid and I'm trying to figure out how to run a 5000 BTU air conditioner. I was hoping someone would be so generous to help me figure out what kind of system I would need to do that. Can you run 5000 BTU AC on a 12 volt battery Bank?

Yes, although it's not recommended due to the surge power you will need to start it.

From my research they run at 5 amps. I'm not sure what the surge is. What size power inverter would I need?

Generally a 2000 watt inverter is safe (since that's what a 120VAC A/C can draw continuously.) You could probably live with a 1000 watt inverter that will surge to 2000 watts, but it's not guaranteed.

I want this setup to be specific just for the AC and nothing else.
So I may be way off but I was thinking even if it ran 24 hours a day that would be around 120 amp hours.

1200 amp hours of battery. 5 amps at 120 volts is 50 amps at 12 volts. Actually closer to 2400 amp hours because you don't want to draw it down more than 50%. So you are looking at about $8K in batteries. Probably $10K or so for the whole system.

Please advise would 4 to 6 Trojan t105 baterry at 12 volt ,450 to 675 amps and 3 to 4 panels 250 watt should handle it? I don't trust my solar math yet hoping someone with some knowledge and experience can help me have an idea so I can estimate price and other factors. I am in Florida so plenty of Sun.

Ha! No.

If you want to run your A/C off solar you have a few reasonable options:

1) Get a grid tie system sized to give you about 14kwhr a day. (cheapest option)
2) Get a smaller grid tie system and do something clever to reduce the A/C's cooling when solar is not available. (LG now has an inverter based window A/C that would work for this; you can reduce the power gradually as sunlight decreases.)

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.

[Sunking]

Thanks sun-king for the knowledge. I warned you I was a newbie and probably off with the math. I have a much better understanding now. Definitely open my eyes a little.

I think could do it if I didn't run AC at night and have six 250 watt panels. That's crazy. But tell me if this makes sense. The AC is 500w. If I run it for 12 hours that's 6000 w of energy use. If I have a 1500 panel times 4 hours is 6000 so I would still be full battery. Or is my Math way off again?

No that is 6000 watt hours, not watts.

Watt Hours = Watts x Hours.

500 watts x 12 hours = 6000 watt hours.

Do not know where you live, but if you live in the south and lucky will get 5 Sun Hours. To use 6000 watt hours in a day, requires the panels to generate 9000 watt hours. So with a 5 Sun Hour Day Panel Wattage = 9000 wh / 5 sun hours = 1800 watts of panels, 2000 to be safe.

That automatically makes it a minimum 24 volt battery system which is still foolish. If you were to do this would use a 48 volt battery system. Economics demand 48 volts. As for the battery no matter what battery voltage you choose is still a 25,000 to 30,000 watt hour capacity battery weighing 1600+ pounds and costing over $4000 every few years. At 48 volts will require a 550 AH battery like 8 of these Rolls 6-CS17P, 6-volt 560 AH batteries. They weigh 221 pounds x 8 units @ $850 each.

Sorry to beat up on you, but I suspect you do not know what you are asking for. Do you have $7000 to $9000 to make that window shaker shake money out of your pockets? Or just pay the POCO a dollar a day for their pockets? Either way you loose, how bad do you want it to hurt? A little or a lot?

[Keith Mo 200]

Thanks sun-king for the knowledge. I warned you I was a newbie and probably off with the math. I have a much better understanding now. Definitely open my eyes a little.

I think could do it if I didn't run AC at night and have six 250 watt panels. That's crazy. But tell me if this makes sense. The AC is 500w. If I run it for 12 hours that's 6000 w of energy use. If I have a 1500 panel times 4 hours is 6000 so I would still be full battery. Or is my Math way off again?

[Mike90250]

Find your needed watt hours in the chart below

Case	Battery style	est co$t	Volt	Ah	Wh each	Qty in Series	Bank V	Total Wh	Useable 50%	3 day Res. Allowed daily drain	est total co$t	cost/wh	Cells to check levels	Interconnects required @ $8 ea	Weight ea
24	"Marine" flooded	$ 95.00	12	90	1080	1	12	1080	540	270	$ 95.00	$ 0.09	6	0	~70
24	"Marine" flooded	$ 95.00	12	90	1080	2	24	2160	1080	540	$ 190.00	$ 0.09	12	1	~70
24	"Marine" flooded	$ 95.00	12	90	1080	4	48	4320	2160	1080	$ 380.00	$ 0.09	24	3	~70
GC2	Golf cart, flooded	$ 95.00	6	190	1140	2	12	2280	1140	570	$ 190.00	$ 0.08	6	1	~70
GC2	Golf cart, flooded	$ 95.00	6	190	1140	4	24	4560	2280	1140	$ 380.00	$ 0.08	12	3	~70
GC2	Golf cart, flooded	$ 95.00	6	190	1140	8	48	9120	4560	2280	$ 760.00	$ 0.08	24	7	~70
31	AGM, Carbon Foam	$ 400.00	12	116	1392	1	12	1392	696	348	$ 400.00	$ 0.29	0	0	~90
31	AGM, Carbon Foam	$ 400.00	12	116	1392	2	24	2784	1392	696	$ 800.00	$ 0.29	0	1	~90
31	AGM, Carbon Foam	$ 400.00	12	116	1392	4	48	5568	2784	1392	$ 1,600.00	$ 0.29	0	3	~90
aa	Rolls "L-16"	$ 861.00	6	546	3276	2	12	6552	3276	1638	$ 1,722.00	$ 0.26	6	1	221
aa	Rolls "L-16"	$ 861.00	6	546	3276	4	24	13104	6552	3276	$ 3,444.00	$ 0.26	12	3	221
aa	Rolls "L-16"	$ 861.00	6	546	3276	8	48	26208	13104	6552	$ 6,888.00	$ 0.26	24	7	221
	Trojan L16 Floor sweeper	$ 225.00	6	380	2280	2	12	4560	2280	1140	$ 450.00	$ 0.10	6	1	115
	Trojan L16 Floor sweeper	$ 225.00	6	380	2280	4	24	9120	4560	2280	$ 900.00	$ 0.10	12	3	115
	Trojan L16 Floor sweeper	$ 225.00	6	380	2280	8	48	18240	9120	4560	$ 1,800.00	$ 0.10	24	7	115

[Sunking]

First all your math is dead wrong. The Window Shaker may pull 5 amps, but that is at 120 Volts AC. At 12 volts taking Inverter efficiency into consideration would pull 65 amps. So to run at 12 volts 24 hours per day would require 65 amps x 24 hours x 5 days = 7800 AH or a 6000 pound $11,000 battery you replace every few years. To charge a battery the size of your living room is going to require. 6000 watt solar panel, and 6 very expensive 80 Amp Charge controllers, and a 6000 pound battery. .

So it is easy to see this is never going to happen and you would be a damn fool to try. Just remember this. Anything you take off grid is going to cost you 5 to 10 times more than buying the power from the POCO. Not only will it cost you a fortune, but also makes you a very heavy polluter. Forget about it.

[Keith Mo 200]

Hello everyone. I've been doing a lot of research on solar I have a small 75 watt set up now but I'm just a newbie. I'm going to be going off grid and I'm trying to figure out how to run a 5000 BTU air conditioner. I was hoping someone would be so generous to help me figure out what kind of system I would need to do that. Can you run 5000 BTU AC on a 12 volt battery Bank? From my research they run at 5 amps. I'm not sure what the surge is. What size power inverter would I need?

I want this setup to be specific just for the AC and nothing else.
So I may be way off but I was thinking even if it ran 24 hours a day that would be around 120 amp hours.

Please advise would 4 to 6 Trojan t105 baterry at 12 volt ,450 to 675 amps and 3 to 4 panels 250 watt should handle it? I don't trust my solar math yet hoping someone with some knowledge and experience can help me have an idea so I can estimate price and other factors. I am in Florida so plenty of Sun.