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Forum Index : Solar : What to expect from a 4.2kw system

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stuart 50

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Joined: 05/10/2010
Location: Australia
Posts: 10
Posted: 04:01am 10 Nov 2010
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Hi group, we recently had a 4.2kw system installed on our north facing roof not knowing to much about solar, i was wondering what sort of out put, dollar savings per month etc we are in Adelaide SA.
Regards.
Stuart

Interested in everything Ham Radio and Solar power
 
Homegrow47
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Joined: 17/08/2010
Location: Australia
Posts: 31
Posted: 04:13am 10 Nov 2010
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  stuart 50 said   i was wondering what sort of out put, dollar savings per month etc we are in Adelaide SA.

Do you know the inclination (tilt) and azimuth (angle from true north) of your panels ?
Also is there any shading ?

 
stuart 50

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Joined: 05/10/2010
Location: Australia
Posts: 10
Posted: 05:23am 10 Nov 2010
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No but ican confirm with the installer.
Stuart


Interested in everything Ham Radio and Solar power
 
Homegrow47
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Joined: 17/08/2010
Location: Australia
Posts: 31
Posted: 05:49am 10 Nov 2010
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  stuart 50 said   No but ican confirm with the installer.


You can use this excellent online calculator to estimate your output.
http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/
 
stuart 50

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Joined: 05/10/2010
Location: Australia
Posts: 10
Posted: 01:23am 11 Nov 2010
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Hi, the pitch is 22, and is facing 10 deg north.
Regards,
Stuart



Interested in everything Ham Radio and Solar power
 
GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 03:18am 11 Nov 2010
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Hi Stuart,

$ savings per month, will depend on what % of the generated power is exported.

Say you use 15kWh/day avg at the moment. this is approx $100/month power cost. A 1kW solar produces on avg say 4kWh/day, so approx 500kWh/month for a 4.2kW system. If half this power was exported, then this generates approx $125/month income at 50c/kWh f i t. the other 250kWh offsets the monthly consumption, so reduces it by 250kWh, so there is 250kWhr still to be paid for = approx $50. so you end up with approx $75/month left, to then deduct the connection fee, approx $15, so approx $60 per month left as credit.

The more power that is exported, the more $ left as credit.

There are plenty of variables wrt how the power is used, and these impact more on the savings, than any calculations based on roof pitch and orientation, and shading etc.

You have to be really wasteful with power to not make a fair bit of $ credit with more than 4kW of solar panels.

Gordon.


become more energy aware
 
Homegrow47
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Joined: 17/08/2010
Location: Australia
Posts: 31
Posted: 04:08am 11 Nov 2010
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  stuart 50 said   Hi, the pitch is 22, and is facing 10 deg north.


What Gordon says is true. about your power usage being the most important, but just as an estimate (assuming no shading, and no electricity usage by you) :

Month Energy (kWh) Value($ at 50˘ FIT)
1  693  346.50 
2  589  294.50 
3  579  289.50 
4  429  214.50 
5  334  167.00 
6  281  140.50 
7  308  154.00 
8  409  204.50 
9  500  250.00 
10  616  308.00 
11  651  325.50 
12  657  328.50 

Year  6,047 kWh  $3,023.5

16.5 kWh per day.

So you should probably aim to reduce you usage during the solar generation time periods (I think they are half hour blocks)

Edited by Homegrow47 2010-11-12
 
stuart 50

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Location: Australia
Posts: 10
Posted: 04:17am 11 Nov 2010
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Hi Gordon, thanks for this, this is about what i thouht but not knowing any body with a solar system was a bit hard to make a discision on what size brand etc we settled with 14 x 319 a sunpower panels with sma inverter $21K, max power generated has been 29 kwh/day, we current are using approximately 40kwh/day, we have a granny flat with a teenager and the usuall heavy power consumption item, solar pool reverse cycle air con etc. we are slowly changing our ways and habits and will be interesting to see what we end up with during the next six months.
Also somebody had mentioned about changing over our 30 + low voltage down lights (50) are there any recomended brands.

Stuart
Interested in everything Ham Radio and Solar power
 
Barry T Coles

Senior Member

Joined: 30/07/2009
Location: Australia
Posts: 109
Posted: 12:13am 12 Nov 2010
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I have tried some with the best being LED 3X3 MR16 Cool White 12v AC/DC.
These are about equilivent in lux to a normal 60 watt downlight with a 51 watt saving & they are cool to touch.

The one I bought was about $19.00, sounds pricey but when you look at a 51 watt saving over a life of from memory 50,000 hours they in my opinion become cheap.

Here's a link to a company in Adelaide

http://www.reflexlighting.com.au/

Cheers
Barry
I need to learn from the mistakes of others.
I dont have the time to make them all myself.
 
stuart 50

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Joined: 05/10/2010
Location: Australia
Posts: 10
Posted: 01:36am 12 Nov 2010
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Hi Barry, thanks for this i will give them a call and possible trial one,
Stuart


Interested in everything Ham Radio and Solar power
 
GWatPE

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Joined: 01/09/2006
Location: Australia
Posts: 2127
Posted: 05:04am 12 Nov 2010
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Hi Stuart,

I have found the cool white LED's to be a quite harsh light. The warm white are a more natural colour.


I would get some of each and test what seems best for you.


Gordon.


become more energy aware
 
petanque don
Senior Member

Joined: 02/08/2006
Location: Australia
Posts: 212
Posted: 03:47pm 12 Nov 2010
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I am in Adelaide as well.

I will suggest about 6500 Kw hrs per year the majority will be produced in summer.
 
GOFJ

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Joined: 22/12/2009
Location: Australia
Posts: 27
Posted: 06:27am 01 Dec 2010
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In Two Wells (a bit north of Adelaide) I have generated 7,000 KWhr since 23/11/08 with 2.6 KW of panels and a Latronics 2500. I have taken (almost) daily readings and put them in a spreadsheet (680 lines deep) and graphed it to produce a interesting trend showing seasonal and weather affected outputs (as well as my mains useage). I don't know how to attach it here but if you PM me your email address I can email it to you.
Jack
 
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