Help with Solar setup

[TheCasualTraveler]

     In a recent Diary by Valterra, Thurmund pointed out,

"Kaneka 60 watt CIGS panels $.98 per watt at www.sunelec.com"

and since reading that and checking out the website I have been thinking I can go solar for a reasonable price where my payback time will be years, not decades.

     My brother is an electrician who has begun doing solar installations and can help me with all the wiring, disconnects and permit but when it comes to specing a system he's still learning. He does installs that are already speced.

     I want to design a simple system and I believe it all centers around the inverter if I want to be grid tied. so,

Available roof area is about 20' X 15' (a little less for spacing between panels for access) which should give room for about 24 panels and 1440 watts of panels. Using the 60 watt Kaneka panels I would like to find a good inverter that will grid tie those panels. (battery charging not nessecsary) I don't want to allow for expansion as that is all the roof area I would use.

     I know where to get panels, I have an electrician, I just need the right inverter. The Sunelec website has quite a few refurbished at low prices and if I can use one of those I can almost eliminate electric bills for about $3,000 US. If I go for the 195 watt panels I could probably take my wattage up to about 2000 watts as they seem to put out more watts per square foot.

     We have for wind turbines a number of designs that can be copied. Maybe we can put together a number of basic tried and true PV arrays to be copied also.

[TheCasualTraveler]

actually, I think cost will be more like $4000 to $5000, but still...

[RandomJoe]

The store I used for my solar parts is Northern Arizona Wind & Sun (NAWS).  They have an example estimate for a 2000 watt grid-tie system here:

http://lib.store.yahoo.net/lib/wind-sun/2kw-gridtie.pdf

The hard part is remembering all the little bits and pieces, so that has a nice detailed listing.  You probably don't necessarily need all the pieces they list there (like com card and datalogger for the inverter) but it's a complete system.

Of course, that doesn't include wire, conduit, junction boxes, sealer for the bolts that hold the mounting racks, all the other misc install materials - so still a bit more to add for total cost.

My system is DIY off-grid, so can't help you much further than that...!  From what I've read of others' grid-tie installs on NAWS' forum the hard part is often making the inspectors happy (most of the time you'll have one from the city, and one from the power company) but hopefully your brother will know what they are looking for.

[wooferhound]

Those Keneka panels are 92 volts

a fairly strange voltage

The SunElec site says they have 1250 more in stock

[TheCasualTraveler]

""Those Keneka panels are 92 volts

a fairly strange voltage""

Exactly Woof, their in lies my question, how to wire approx. 1440 watts of those panels and match it to an (under $2000) grid tie inverter.

I'm figuring about $1500 for those Kaneka panels, $2000 for the inverter and $1000 for misc. materials that my brother will get wholesale and inexpensive. He buys up disconnect boxes and stuff in lots. Permit will run about $100 and I can pick up the panels.

So, how to mix and match? I could call Sun Electronics but I feel more secure about advice from here.

[imsmooth]

I have a 12kw system with three 3.3kw Sunnyboy grid-tie inverters.  Each inverter handles 4kw of panels. I have had no problems.

[halfcrazy]

look at the Xantrex GT inverter they also have a string sizing tool so you can get that part right as well I think there limit is 550 volts dc but do not remember so maybe 5-6 panels in a string?

[wdyasq]

The panels are "60V" with a 92V Peak.  They are also about 10SF each. 25 Panels will be about 250SF.

"Day tracking" will add a lot to your production. With only a couple of moves a year for seasonal adjustment and day tracking, one can achieve very high panel efficiency.

Here, in North Central Texas with good sun and $0.15/kW power costs, one might gross $54 a month in power from a setup as you propose, using day tracking. You could deduct about 40% for fixed panels.

At $2000 for a grid tie inverter, it will take about 40 months just to pay for the inverter, not counting the extra meter the electric company may require or the meter reading fee.

Notice we have yet to include the panels, mounting brackets, tracker or wiring.

I don't think PV is, at this time, a viable "economic" investment. I do believe it may become very economical if the 'cap and trade' scam is passed.

A lot will also (in Texas) depend on the rules and attitude of the local utility company. some are a lot more aminable than others toward RE and buying bsck the electricity.

Ron

[TheCasualTraveler]

Thanks, I looked at the Xantrex chart

http://www.xantrex.com/support/gtsizing/index.asp?lang=eng#calculator

I selected the Kaneka panels

and if I read it right, 4 modules in 6 strings would give 1440 watts and require at least a Xantrex GT 2.5 inverter. Pretty cool, if I did it right.

Sunny boy also has a calculator. What a great help, Thanks.

[TheCasualTraveler]

Although, I think once I add in Government incentives/ rebates this may just work.

[Airstream]

(The second figure is the 'initial' outputs..)

Nominal peak power (Wp) 60,0 79,0

Guaranteed minimum power (Wp) 57,0 75,05

Nominal voltage (V) 67,0 74,0

Nominal current (A) 0,90 1,04

Open-circuit voltage (V) 92,0 96,0

Short-circuit current (A) 1,19 1,22

530 Maximum System Voltage

7.0 Fuse Rating (A)

That 92~V open circuit and the 7 Amp string fuse rating...

530 / 96 = 5 in series using the OEM specs initial value PDF...

Looks like twenty panels, four strings of five is well below the 7 Amp rating.. But I get the heebee jeebies just thinking about 480VDC knowing where I sleep :/

[chainsaw]

Not knowing your geographical location to enter in PV watts I tried several locations, shows about 1800 to 2300 kwh per year(depending on location) for a 1.4 kw grid tie system. 2300 kwh per year would be 191 kwh per month. Using .12 per kw would equal approx $23 credit per month on your electic bill. A lot of utility companies will tack on some extra fees for net metering.

[bzrqmy]

Are these Kaneka panels the breakthrough in the price barrier for solar that I have been waiting for?  Is there more to come?  Will we ever see the sub $1000 grid tie inverter?  Will residental solar be like the satellite dish is today where everyone can have one on the roof?

[kenl]

There are 3 Kaco 1500 grid ties on ebay right now with a start price of $550. Would fit right into your plans. The guy had them listed last time for $799 starting bid.

kenny

seemed like a good idea at the time