So I bought 1800 watts of panels. . . now what?

[inetdog]

Once again it is a simple math formula Watts = BTU's / SEER. A 4-ton AC unit has a cooling capacity of 48,000 BTU's

Just to avoid any confusion on the part of those who are following this: BTUs are a unit of energy, like Kwh. The corresponding unit of power, which Sunking is referring to, is BTU/hour.

This is made even more confusing by the fact that a 4 ton AC designation is originally derived from the cooling produced by 4 tons of ice per hour.

So much for dimensional consistency. (Unlike most figures of merit, SEER was defined in a way which makes it dimensional. That means that a SEER of 1 does not hold any special place in the system.)

[cashaber]

Just to avoid any confusion on the part of those who are following this: BTUs are a unit of energy, like Kwh. The corresponding unit of power, which Sunking is referring to, is BTU/hour.

This is made even more confusing by the fact that a 4 ton AC designation is originally derived from the cooling produced by 4 tons of ice per hour.

So much for dimensional consistency. (Unlike most figures of merit, SEER was defined in a way which makes it dimensional. That means that a SEER of 1 does not hold any special place in the system.)

The AC guy came by today and confirmed my estimated wattage useage on my unit about 3900watts plus about 700 watts for the inside unit. he also stated that the unit doesnt run on watts (important of determining teh correct inverter to use in a solar system) and runs on amps which are 19. the voltage(197-240) also is a mid range and can use more or less depending on stress factors. Also he said its prob a 9 or 10 seer system which in the 90's was a very high rating back then.

[inetdog]

Also he said its prob a 9 or 10 seer system which in the 90's was a very high rating back then.

That makes a lot more sense. Would you care to apologize to Sunking?

Now his statement that it runs off Volt-Amps rather than watts has a glimmer of truth to it, but does not really make sense the way you describe it.

The A/C requires a certain number of watts, which will have to come out of the batteries via your inverter so you must know this number. A Kill-a-watt or similar meter could tell you this if there were a way to safely connect it to your A/C. But it also requires a significantly (for older units especially) larger number of volt-amps which will have to come from the inverter and have to be within its capacity too.

[cashaber]

Replys in sentance in bold

That makes a lot more sense. Would you care to apologize to Sunking?

No.. I feel that he should be the one apologizing, or not

Wrong, wrong, wrong, dead wrong. You made a huge flaw. Your AC unit uses a lot more than 3300 watts and a 5000 watt battery inverter would shut down immediately when you AC unit starts up.

btw Sunking I am female not male


Now his statement that it runs off Volt-Amps rather than watts has a glimmer of truth to it, but does not really make sense the way you describe it.
This was before the AC guy came out and said my AC ran off amps not watts, now that might have been a mishap at least in part. for that I am sorry.. but maybe some one can explain how this works. but as for my Wattage calculation I was very close to the ballpark of 3900 watts.

The A/C requires a certain number of watts, which will have to come out of the batteries via your inverter so you must know this number. A Kill-a-watt or similar meter could tell you this if there were a way to safely connect it to your A/C. But it also requires a significantly (for older units especially) larger number of volt-amps which will have to come from the inverter and have to be within its capacity too.

I wont have any batteries attached to my system. thus the inverter size I use as long as the input from panels/wind does not exceed the inverter rating will not shut down the inverter while being connected to the grid. excess electricity will be pulled from the grid

[inetdog]

Replys in sentance in bold
I wont have any batteries attached to my system. thus the inverter size I use as long as the input from panels/wind does not exceed the inverter rating will not shut down the inverter while being connected to the grid.

Shutting down the inverter based on load is not an issue with a grid-tied system. The difference between watts and VA will be supplied happily by the grid and you will not be charged anything for it. It does not represent any actual energy use. As for the inverter shutting down from excess input, that depends on the exact model inverter you have. Many will just not take more of the available power than they can safely use. That, in turn, can cause control problems for a wind system. Read the various threads on this forum for the reason not to expect anything good from small wind, despite the advertising and youtube videos (also advertising mostly.)

The relationship among watts, VA and power factor and the reason that the difference even exists is complicated enough that I would recommend that you look it up on the Internet and come back with any specific questions you may have. I don't feel that I can do a good job of the entire explanation in this context.

PS: Sunking was impolite, but right. You were impolite and wrong. Both are undesirable, but your position is less tenable.

[Sunking]

To bad I dont have a 22 Seer TRANE

OK this is where you are getting into trouble. You said you had a 4 Ton Trane unit rated SEER 22.

[Sunking]

The AC guy came by today and confirmed my estimated wattage useage on my unit about 3900watts plus about 700 watts for the inside unit. he also stated that the unit doesnt run on watts (important of determining teh correct inverter to use in a solar system) and runs on amps

Then you need to find a different Mechanical Contractor because this one does not know what he is talking about.

OK if your AC unit is a 4-Ton unit, which is a typical size unit for a home of about 1200 to 1600 square feet, and consumes 3900 watts means its SEER is 48,000 BYU's / 3900 watts = 12.3 SEER. In the 90's that was about average and nothing special, 14 to 16 was the high end in the 90's.

Now I am going to give you the best advice you will ever get. Forget Solar right now for many reasons.

• You live in TX where electricity is dirt cheap
• You live in TX where we have no Net Metering laws except except on the left coast of Austin area. That is why they have to pay more for electricity than the rest of the state

Instead of Solar right now upgrade your current cooling system first as it will pay for itself a whole lot faster and add more value to your home than a solar system will add. In TEX Solar systems only add about 10% of the initial cost (90% net loss before you turn the system on) to the value of your home because electricity is dirt cheap here and there is not much added value to having solar in TX.

Lastly as we have tried to tell you many times the size of the grid tied inverter is irrelevant to the load demand you have in your home. If the inverter is producing less than what you are using, the shortfall comes from the grid and you are buying the power. When and if your inverter is producing more power than you are consuming, the excess is sold to your neighbors.

[cashaber]

OK this is where you are getting into trouble. You said you had a 4 Ton Trane unit rated SEER 22.

No you said that I said I had a 4 ton AC

like you your quote from my quote I said

too bad I dont have a 4 ton AC

[Sunking]

too bad I dont have a 4 ton AC

You changed your story again getting you caught. Go back to page 2, post 17 and I quote you directly:

but it is a 4 ton AC
================================================== =======================

[cashaber]

OK this is where you are getting into trouble. You said you had a 4 Ton Trane unit rated SEER 22.

PS my AC is not a HUGE 22 seer TRANE hell it doesn't even say a seer rating on it. but it is a 4 ton AC
================================================== =======================

and the Too bad I dont have a 4 ton AC (this was cut off ment to say 4 ton Trane AC)


Dude you really have to let this go

[cashaber]

Then you need to find a different Mechanical Contractor because this one does not know what he is talking about.

OK if your AC unit is a 4-Ton unit, which is a typical size unit for a home of about 1200 to 1600 square feet, and consumes 3900 watts means its SEER is 48,000 BYU's / 3900 watts = 12.3 SEER. In the 90's that was about average and nothing special, 14 to 16 was the high end in the 90's.

Now I am going to give you the best advice you will ever get. Forget Solar right now for many reasons.

• You live in TX where electricity is dirt cheap
• You live in TX where we have no Net Metering laws except except on the left coast of Austin area. That is why they have to pay more for electricity than the rest of the state

Instead of Solar right now upgrade your current cooling system first as it will pay for itself a whole lot faster and add more value to your home than a solar system will add. In TEX Solar systems only add about 10% of the initial cost (90% net loss before you turn the system on) to the value of your home because electricity is dirt cheap here and there is not much added value to having solar in TX.

Lastly as we have tried to tell you many times the size of the grid tied inverter is irrelevant to the load demand you have in your home. If the inverter is producing less than what you are using, the shortfall comes from the grid and you are buying the power. When and if your inverter is producing more power than you are consuming, the excess is sold to your neighbors.

hi.

ok first off the AC if from the early 90's 1992 about time for it to go out maybe that why it did.. it froze up last friday night. as long as we have the sears maint contract. hopeing that they'll replace it.. today they just put in some stop leak and topped off the freon (dunno how to spell that) anyways not important.
waiting for sears to deside to replace the unit.. there spitting the bill.


as far as me going Solar... I dont really care about how cheap were paying currently $0.067khw plus like $24/mo brings it to around $0.08/kwh.
Net metering is not available in TX as of yet but there are rebates from them. a net meter is still required to have on a gti.
even if I'm not feeding the grid.

http://dfwnetmall.com/energy/texas-energy/net-metering-oncor-rebate.htm

more info here

http://www.solarcity.com/campaigns/tx/11/txu-solarlease.aspx

TXU has a Service that you can do your whole house and pay about $4000 or less for Solar lease for 15yrs
however you do not own the equipment and the ave monthly bill is around $40/mo for the lease in which you get free grid electricity at least most of the time

http://www.star-telegram.com/2010/02/23/1991849/new-txu-solar-power-venture-drops.html

ok with that said..... I want to get a solar grid up because I want to do it. not to save money on my electric at our rates even in 15 yrs solar wont pay for its self
unless it goes back up to $0.20 again.

I want to do Solar cuz I wanna it will be good fun to learn this stuff, at least I thought I did until recently .Same reason as I want the Ferrari not the pinto. Solar or wind makes no differance at least I am getting my foot in the door. However a wind turbine seems to be a good place as any to start.

[inetdog]

Solar or wind makes no differance at least I am getting my foot in the door. However a wind turbine seems to be a good place as any to start.

Wind will certainly be exciting, but only in a negative way.
1. You need measured sustained winds in the 12 MPH and up range to get a practical amount of energy from a small turbine. Regardless of how many blades it has or at what speed it starts to spin. The maximum energy available for a perfect turbine with the same collection area (cross section to the wind) will go up as the cube of the wind speed.
So 10mph will produce 8 times as much energy as 5mph. And the rated output of a turbine is measured at, I believe, about 25mph. So even at 12 mph, you will be getting at most 1/8 of the rated output.
2. Many of the available small wind turbines will cheerfully self-destruct in a wind much above 30 mph despite your best efforts to save them.
3. You will normally need a 50 foot or higher guyed tower away from any buildings or trees. That is a substantial expense to get your foot in the door.
4. Roof mounting the turbine instead will drive you crazy from the vibration and will still not produce useful power.

For more details and for the references to back this up, search other threads.

Solar is a much better place to get started than wind, unless you are in it for commercial purposes and are looking for investors.

[cashaber]

Wind will certainly be exciting, but only in a negative way.
1. You need measured sustained winds in the 12 MPH and up range to get a practical amount of energy from a small turbine. Regardless of how many blades it has or at what speed it starts to spin. The maximum energy available for a perfect turbine with the same collection area (cross section to the wind) will go up as the cube of the wind speed.
So 10mph will produce 8 times as much energy as 5mph. And the rated output of a turbine is measured at, I believe, about 25mph. So even at 12 mph, you will be getting at most 1/8 of the rated output.
2. Many of the available small wind turbines will cheerfully self-destruct in a wind much above 30 mph despite your best efforts to save them.
3. You will normally need a 50 foot or higher guyed tower away from any buildings or trees. That is a substantial expense to get your foot in the door.
4. Roof mounting the turbine instead will drive you crazy from the vibration and will still not produce useful power.

For more details and for the references to back this up, search other threads.

Solar is a much better place to get started than wind, unless you are in it for commercial purposes and are looking for investors.

hi lets take this to this thread

http://www.solarpaneltalk.com/showthread.php?8062-Starter-Solar-wind-GTI-System-NO-Batteries-would-like-some-help-500-startup-cost&p=53887#post53887

[ripjohnnyc]

If you wire 12 volt batteries to 24 volts you will need a 24 volt inverter

Thanks!

So lets get this thread back on track so I can finally get some electricity in here! lol.

I did everything that has been suggested so far, 660 A/h battery bank wired to 24v. Got a midinite classic 150, 24 v 2000w inverter and 1880w of solar panels. Now I am trying to figure out what I need in a solar combiner box. How do i go about figuring out what amp breakers I need per panel, would it be the "short circuit rating" listed on the back of my panels?

[mordarlar]

I'm glad you're pushing forward with your plans ripjohnnyc. We actually lived off grid for a year in WV using 560 watts worth of panels. We had an outback flexmax 60, a free bank of batteries (some companies give them away when they upgrade) and a cheap 2500/5000 peak inverter. We ran just about anything, excepting an ac unit and the fridge. This included, although some things could not be run together, led tvs, light, desktop and laptops, the vacuum, the kids games and toys... We didn't run things like high watt small appliances and things with heating elements (instead we would use items like the non-electric french press...) We also would not have been able to run our household things and a water pump simultaneously.

On the very short days of winter, when we were first able to set up our battery bank, the days were running pretty short due to the fact that we lived in a hollow and the hills went up all around. We would have trouble completely filling the bank but we were able to run the things mentioned above nearly every day and often into the night. We supplemented on the very dim stretches with a generator.

I realize this isn't overly technical, that is more my husband's dept. but we were quite comfortable with our little set up and i can assure you it was certainly possible with some care and thought. Our set up cost us a little over $2500 several years ago.