400kwh for air conditioning for one month

[TheeBigGuy]

According to my electric bill I jumped a little over 4ookwh for central AC... I set it to 78 and on average for this month 5 hours a day... There must be an alternative to this... Ductless mini split (they fluctuate between 500 and 1000 watts an hour depending on demand) through a 2.4kw mppor 3kw growatt all in one? That way during daylight hours it would run for free?..And if I did that I do not need a big 24v battery bank? Any suggestions...thanks

 

[gnubie]

I'm guessing you want to aircondition just one room? It's going to come down to the size of the room, the quality of the insulation and the desired temperature. That will say how long the aircon has to run to maintain the room at a given temperature. If you nominate a given mini split unit it will have typical use figures that could be used to work out power consumption from, but it would need to be sized for the room you are attempting to cool for those figures to be meaningful.

 

[TheeBigGuy]

I'm guessing you want to aircondition just one room? It's going to come down to the size of the room, the quality of the insulation and the desired temperature. That will say how long the aircon has to run to maintain the room at a given temperature. If you nominate a given mini split unit it will have typical use figures that could be used to work out power consumption from, but it would need to be sized for the room you are attempting to cool for those figures to be meaningful.

A high seer around 24 will be rated at usually at 8 to 10 amps at 110 volts..But they all have variable inverters where once the room which is my living room kitchen meets your desired temp..It may drop all the down to 4 amps or even lower.. Im in a well insulated home...My real question is an all in one like the lv2424 or growatt 3kw the cheapest way to run 10 amps from 10am till 6pm during the summer months..Being in the high desert our overnight always cools off...

 

[mopat]

I do not need a big 24v battery bank

The LV2424 and Growatt both require a battery bank for operation.

 

[TheeBigGuy]

The LV2424 and Growatt both require a battery bank for operation.

I realize they need a battery...But we run AC during the day... From my understanding lv2424 or growatt with solar can power a 1000 watts during the day.. What I am trying to do is offset 400kwhs with solar.. And a lv2424 or growatt with one 100amp hour 24 volt agm battery is all I need.. Trying to keep cost way down...Buying individual parts for a system cost way more than an All in one....

 

[schmism]

What I am trying to do is offset 400kwhs with solar.

You have 2 choices, install one growatt and run 3000w of 110v off it. or install 2 and run them in parallel split phase 220v. Either way both are 3kw. Either choice you still have to have a "critical loads" panel for the inverter(s) to power as they cant sell back to the grid, so you just can't tie them to your main panel.

Your single battery dont do much for you, I suppose you could configure the inverter to "never" use it. You'll have to ensure your settings are correct for the small battery due to the limited C rate you'll have.

 

[Craig]

Yes they will support the AC I would double the panels though say 2Kw so that you can create enough energy because panels rarely output full power. you could get by with a relatively small battery. Im guessing less than $1000.00 for panels plus the growatt and a 100Ah battery

 

[CompMan2020]

The inverter works in tandem with the batteries, once solar dips down it will use the battery bank to keep the loads running. If your bank is too small it will want to pull from the grid if available . You will need a large solar array and or bank to keep it running completely off grid during the day. 100AH of AGM is really 50AH since you don’t want to go below 50% SOC.

 

[schmism]

He can configure the growatt to only use battery if grid is down.

 

[CompMan2020]

He can configure the growatt to only use battery if grid is down.

True. But if the array is too small the inverter will be constantly switching back to grid power. I guess it will save some money, but it will be a bit before he sees a return on the investment.

 

[TheeBigGuy]

Yes they will support the AC I would double the panels though say 2Kw so that you can create enough energy because panels rarely output full power. you could get by with a relatively small battery. Im guessing less than $1000.00 for panels plus the growatt and a 100Ah battery

I was hoping to hear what you said but the only problem I see is the growatt 24v 3kw has a max pv input of 145 vdc... How do I hook up 2kw of panels it would far exceed the 145 vdc.... thanks

 

[mopat]

How do I hook up 2kw of panels it would far exceed the 145 vdc

Maybe not so. Probably a panel arrangement of 3-series and 3-parallal would keep Voc<145VDC.

 

[schmism]

How do I hook up 2kw of panels it would far exceed the 145 vdc.... thanks

That's going to depend on the panels you choose to use. The smart choice is large 250-350w panels that are typically 40-50v each panel. Several panels are connected in series (the voltage adds, typically 2-3) several series groups are connected in parallel (the current adds).

Based on your question it would apear as if you have plently of reading/learning to do in your future before you attempt a project on this scale.

 

[Craig]

I was hoping to hear what you said but the only problem I see is the growatt 24v 3kw has a max pv input of 145 vdc... How do I hook up 2kw of panels it would far exceed the 145 vdc.... thanks

Yes it all depends on yur configuration of panels. with 40v panels do 3 in series then 3 parallel strings of those. Also your MPPT I think is 80 Amps at 24v so the max energy you can process is 24 X 80 or 1920 Watts. But again you want a few more watts than necessary so that you always have full production and do not wear down battery.

 

[MichaelK]

If you somehow think that an off-grid solar system is going to save you money on air-conditioning, you are very much wrong. Off-grid solar is the single most expensive form of electricity. The only time this type of solar is cost-effective is when there is no grid to tie into. The combination of the battery bank sized to adequately run your loads, coupled with all the electronics to run it, gets quite expensive.

A much more cost-effective solution for your situation is a grid-tie, where you are getting a credit for the amount of electricity you produce. The contracts though vary widely from one jurisdiction to the next. The best kind of contract features net metering, but most contracts today are far less lucrative. For example, the power company buys every watt of electricity from you at 5Ç a kWh, and sells it back to you at 15 Ç a kWh.

Do I use solar; absolutely. Do I have air-conditioning; absolutely. But I have a cabin what is 15 miles from the nearest power pole, so that what makes solar air-conditioning cost effective.

 

[Trukinbear]

If you somehow think that an off-grid solar system is going to save you money on air-conditioning, you are very much wrong. Off-grid solar is the single most expensive form of electricity. The only time this type of solar is cost-effective is when there is no grid to tie into. The combination of the battery bank sized to adequately run your loads, coupled with all the electronics to run it, gets quite expensive.

A much more cost-effective solution for your situation is a grid-tie, where you are getting a credit for the amount of electricity you produce. The contracts though vary widely from one jurisdiction to the next. The best kind of contract features net metering, but most contracts today are far less lucrative. For example, the power company buys every watt of electricity from you at 5Ç a kWh, and sells it back to you at 15 Ç a kWh.

Do I use solar; absolutely. Do I have air-conditioning; absolutely. But I have a cabin what is 15 miles from the nearest power pole, so that what makes solar air-conditioning cost effective.

I've spent over $26,000 on mine and that is with me doing all the work, design, and transportation of large items - I went to the manufacturer in San Leandro for my battery, over to Wholesale Solar in Shasta for my panels, and up to Portland for my generators. You'd save more money if you put your dough into insulation, or a more efficient system like a heat pump. NOTHING is cheaper than grid power!

 

[CompMan2020]

I’m afraid these guys are right. I’ve learned the hard way that solar power isn’t cheap. My main reason in investing so much into my system is that I’m in Florida and we have hurricanes passing thru a few times a year. Grid tie is useless when the grid is down. Hence a large battery bank / Solar array and a off grid inverter for the essential loads.

I was prepared for Erma, but Gas generators need a lot of up keep and gas is scarce before and after a hurricane hits. Not a fan of waiting in line all day long for just a few gallons of gas. Solar solves that a bit.

Like I said before, you will save money with a solar system, but it will be a while before you start to see a return in your investment. Especially if it’s just to power a small AC unit.

 

[Hedges]

NOTHING is cheaper than grid power!

PV panels and inverters are cheaper than grid power.
Batteries are more expensive than grid power.

I figure grid-tied PV costs me $0.05/kWh, while grid power costs me $0.15 to $0.45/kWh
Best use is net metering, so we get back every kW we produce without paying for batteries. (or 3 kW per kW, or 1/3 kW per kW, depending on time of day.) But at my prices, I win with PV regardless.

Without net metering, PV installed for no-export would still save money so long as I consume at least 1/3 of what it produces, curtail output no more than 2/3 of what it could have produces.

So I think using grid-tie PV inverters configured for no-export, offsetting A/C power consumption, could be worthwhile if you run A/C most of the time. (or any other loads)

 

[Trukinbear]

PV panels and inverters are cheaper than grid power.
Batteries are more expensive than grid power.

I figure grid-tied PV costs me $0.05/kWh, while grid power costs me $0.15 to $0.45/kWh
Best use is net metering, so we get back every kW we produce without paying for batteries. (or 3 kW per kW, or 1/3 kW per kW, depending on time of day.) But at my prices, I win with PV regardless.

Without figuring in the price of my battery I'll break even November 2041... after that it might be cheaper, though probably that is longer than my system will last. I know I won't be alive to see it at any rate.

 

[Trukinbear]

PV panels and inverters are cheaper than grid power.

If you paid for all those Sunny Islands in your avatar how can your cost be 5 cents a kilowatt?