All things Solar (merged threads)

[Franco Cozzo]

Do any of you guys have a battery bank along with your solar system just in case you get an outage?

[poppa smurf]

only stating what I have found on most solar websites and is sprouted by most solar experts.....generally accepted throughout that 6 hours is average

so far I am well above the 6 hours a day, most days I am producing over 12 hours at variable rates

but that will drop when winter comes...however at this latitude our winters are very mild......thats where the average comes in

[poppa smurf]

Originally Posted by Big Damo

Do any of you guys have a battery bank along with your solar system just in case you get an outage?

no, but have thought about a small backup system to "energise" the inverter to enable the basics like lights and such like

haven't looked into that as yet!......dont know what would be needed or how to safely "back feed" power into the system

may have to go back to the knowledgeable expert folk on the solar forum to get some answers

[z80]

Originally Posted by poppa smurf

only stating what I have found on most solar websites and is sprouted by most solar experts.....generally accepted throughout that 6 hours is average

so far I am well above the 6 hours a day, most days I am producing over 12 hours at variable rates

but that will drop when winter comes...however at this latitude our winters are very mild......thats where the average comes in

yeah...6 hours a day of sunshine....but...

A good proportion of hours either side of that 6 hours are not at full capacity.

Unless you have a mechanical tracker that moves the panels to be directly at the sun for the full 6 hours?

[dave351cid]

Originally Posted by Tribal

Sorry if its been answered already - but for those who are on Solar - what happens when there is a power outage? Does your system keep you self sufficient or are you still at the mercy of the energy providers?

no.. if the mains power goes off, so does the solar power.

Originally Posted by Stagg1991

If it's during the day you will still have power from the system, if you use more than what is being produced than the system trips out.If it's at night then your still at the mercy of power companies, yes.

hmmmm..... certainly not in QLD. maybe VIC electricity is different.
if the mains power supply is cut for any reason the the inverter will turn off immediatly. otherwise how am i going to fix the broken lines if the street full of solar systems are feeding power back into the grid when its supposed to be isolated and earthed.

[Tribal]

Originally Posted by dave351cid

otherwise how am i going to fix the broken lines if the street full of solar systems are feeding power back into the grid when its supposed to be isolated and earthed.

I had a feeling this would be the answer.

Its a shame that the smart meters can't stop the flow during an outage - but still allow the house/site to be powered locally - until the power company sends a signal to the meters to allow the current flow again when services have been restored... but you would need batteries to do this?

[poppa smurf]

Originally Posted by z80

yeah...6 hours a day of sunshine....but...

A good proportion of hours either side of that 6 hours are not at full capacity.

Unless you have a mechanical tracker that moves the panels to be directly at the sun for the full 6 hours?

you will never get "full capacity" out of any system, you will however get solar time...and it is this solar time that makes an average that makes up the numbers.....the closer to the equator you place the panels the more solar "time" you will get

solar only ever runs at 75% - 80% of spruked numbers at the best of time, the cheaper systems will not even achieve this but daylight hours makes up the total average

as for 6 hours of sunlight ........ATM we are receiving between 12 and 14 hours of usable productive light in a rising and declining scale.....our system is producing 21 kilowatts around 1 or 1-30

anyway as I stated before....we are averaging 21 kilowatts per day out of a 3.5 kilowatt system, and have been for the last 5 months and we are very happy with the system

I'm sure if you don't want solar for what ever reason there are a million excuses to not put it on

[Stagg]

Just to get super-duper technical with everyone here, as everyone seems quite technically minded:

Depending on which panels you get, it can make more power or less power from the same sized system, and how that is determined is by the systems Broad Spectral Response.

Each cell has a different efficiency (15%, 18%), that we all know, But what you must remember is that under different light conditions, it has different efficiencies. So for example, a 5kW system with a mediocre chinese brand may make about 20kWh during a summers day, and a comparative German 5kW system may also make 20kWh during the same day.

However, say the day is slightly overcast and rained a little, the chinese 5kW system may make 10kWh and the German 5kW system may make 15kWh under the same conditions.

What causes this is when the panels are negatively earthed. You see, a PV cell is like a sandwich; negative terminals are wired to either the front or the back, positive terminals are wired to the front or the back as well. What will happen with most panels which are a fair bit cheaper, is that it is not required to earth the positive wire, and in sunlight, the cell actually has a static discharge on the surface of the cell. This means that the efficiency drops, especially under low light conditions.

With the premium modules, you will commonly find that it is a requirement for the cells to be positively earthed, and the front of the module is wired to the positive terminals. This will cause a vaccuum-like effect on the module, eliminating the static charge on the surface of the cells, increasing both the daylight efficiency and the low light efficiency of the cell.

Further advancements can be made depending on the manufacturer. For example, SunPower has a process for their cells called doping; where the top layer of the cell is dipped in Phosphorous, and the bottom layer is dipped in Boron. The reaction that happens in sunlight is that photons that are in contact with the Phosphorous layer are sucked into the Boron layer, thus increasing the cells efficiency.

Here is a PDF that explaining such benefits with going to a premium panel:

http://www.perfectpowernetwork.com/p...nt_Testing.pdf



There is much more to solar cells than just a silicon cell in a frame, however when it is just simply that, do not expect the cell to perform as well as those which are tested and improved to gain higher efficiencies; SunPower currently has a cell which is 25% efficient!!

[Stagg]

P.S. Have a look at the Broad Spectral Response

[poppa smurf]

absolutely agree with this ^^^ statement 100%....my neighbour had a 1.5 kilowatt chinese system installed

we have been watching the figures and it is not real good, the panel is "the generator" so it pays to buy good ones

heat also makes a HUGE difference, I find the perfect day to be around 20 -25 with a light breeze, cloudless of course

I have been down to 13 kilowatts on a cloudless day with temps up around 39 degrees and very strong sunlight, which strangely enough, the panels don't like

my panels were placed after much thought and many calculations from many inputs.....they are as close to a "perfect" position as non movable panels can be.....

[z80]

The secret to good choice of panels is to start with monocrystalline panels.

They cost a wee bit more but have a better temperature rating.

[Stagg]

Originally Posted by z80

The secret to good choice of panels is to start with monocrystalline panels.

They cost a wee bit more but have a better temperature rating.

Another aspect that is not considered by many is purchasing panels with the Busbars correctly soldered to the face of the cell.

When there are bubbles in the Busbar, what that does is significantly reduces the total DC voltage that is flowing throuh the cell, and greatly diminishes the total output of the modules. It also causes the face of the cell to become hotter, which also reduces the performance of the cell. If you were to measure it, a 175 watt panel with bubbles in the busbar may only be pushing out 150 watts or less.

These bubbles are caused when they are soldered on by hand, instead of by machine.

When you buy panels, inspecting the busbars on your own panels will ensure that you won't have a drop in efficiency for an unknown reason from when they are installed on your roof.

By the way the Busbars are these:

[BPXR6T]

Yep, I just spent a couple of years on a remote property with 100% solar generation via a 4.5kw BP Solar system. Great setup and I only recall using the diesel backup generator on a few occasions during winter. Now back in the big smoke paying for electricity again. When I buy my next place I'll be going solar again.

[poppa smurf]

had my first meter reading done yesterday.....it will be interesting to see what the numbers actually crunch down to......this will be my first full reading with the solar in full operation

from memory I reckon the BP panels are recognised as the best in the business!.....with REC a close second

solar is getting very affordable now!.....I would still have it even without the feed in tariff

[deesun]

I have just installed a 5kw system in QLD. I have 24 panels which add up to 6kw and a 5kw inverter. Panels are Mono crystaline A grade and inverter SMA 5000TL. Price $11990. My roof faces directly north and all panels are on the same section. My installer came twice, once to rough measure and give us the info and the second time to sign us up. There were a couple of phone calls from us too. The last time was after the inverter was approved and when asked he said 4 weeks, when he realised the inverter was approved he said how about tomorrow, so now its on. About 4 blokes rocked up at about 11am and all done by 5pm.
Whilst getting quotes we encountered all types of sales people from the really pushy to the not so. But most quotes were not too far apart. I used this site for info which I found very good http://www.solarquotes.com.au/index_a.html. I also found or was given a site which allows comparisons between panels, sorry cant remember it. Only time will tell how long it takes to pay for itself but installer reckons 3.5 years. Elec companies here in QLD are paying between 44 and 52c pkwh so check that also.
Happy solaring.

[poppa smurf]

that's a pretty good price!.....you must have the 220 watt panels giving an output of 5.280 kw.....a good system

I agree with your installer on the time frame it may possibly also be a bit shorter than that.....maybe even around 3 years and it will be paid for at .44c per kilowatt

should easily cover your power needs

[deesun]

Originally Posted by poppa smurf

that's a pretty good price!.....you must have the 220 watt panels giving an output of 5.280 kw.....a good system

24x250w

[z80]

Here's a satellite photo of my panels.

(Google earth is so clear nowadays.)

Still more panels to be installed, (some shed space left)

Currently about 78 panels with 3 inverters....accumulated over 20 years.

All are BP monocrystalline panels.


Something I always wanted to do and have done it...self sufficiency.

The excess power also drives a desalination unit converting seawater into drinking water.

[poppa smurf]

Originally Posted by deesun

24x250w

good setup...will easily be paid off within 3 years.....what brand are your panels?

Z80.....well done, very nice array......can i ask why you didn't have them placed at ground level on stands

mine are due to be cleaned again and I'm not looking forward to poncing around on the roof again.

given the choice I would have mine on the ground for ease of access

[davenl5l]

thinking of going solar good info here thanks everyone...but as a retired plumber(not my choice caring for sick wife) i am surprised there is no mention of heat pump hws's these are eligable for rec's replace a std mains hws work 24 hrs a day cost similar to a solar hws but without the extra plumbing and roof support and are nearly as efficiant as solar

[Stagg]

Originally Posted by davenl5l

thinking of going solar good info here thanks everyone...but as a retired plumber(not my choice caring for sick wife) i am surprised there is no mention of heat pump hws's these are eligable for rec's replace a std mains hws work 24 hrs a day cost similar to a solar hws but without the extra plumbing and roof support and are nearly as efficiant as solar

Hey mate, heat pumps are a solution only in some areas of Australia.

They work on ambient heat, which for example in Queensland, there is an abundance of.

However, here in Victoria, they do not work so well, because there is very little humidity on the air for the majority of the year.

You also have to consider that a heat pump uses electricity rather than gas, so we have to compare its efficiency with an electric boosted solar.

A heat pump it at its most efficient during the day, understandably because it is hotter during the day than at night. That means that the heat pump will run on peak power i.e. will run whenever the temperature drops below 60 degrees, including running at night.

An electric boosted solar hot water is more efficient when the element is connected to off peak power and runs at night, because you are able to get maximum solar contribution during the day, and the booster is able to top up the temperature at night. A solar hot water system will still work in Victoria, because the copper pipes are enclosed in the collector panel.

Do you remember those cold but sunny winter days, where you would need to wear sunnies but still a scarf because of the cold wind, but then you go to hop in your car that was parked in the sun, and it was still fairly hot in the car? that's exactly how solar hot water works

FYI everyone here, in Victoria we actually save more money buying solar hot water than you do in Queensland, a confusing truth but I'll explain if any one wants to know

EDIT: In my two years in the industry I have not sold a close coupled system that needed roof support, it's not a myth that some need support though, but the occasion has never arisen.

[poppa smurf]

Originally Posted by davenl5l

thinking of going solar good info here thanks everyone...but as a retired plumber(not my choice caring for sick wife) i am surprised there is no mention of heat pump hws's these are eligable for rec's replace a std mains hws work 24 hrs a day cost similar to a solar hws but without the extra plumbing and roof support and are nearly as efficiant as solar

I dont reckon you could go wrong with solar, particularly as the price is dropping so rapidly and power costs rising....

my son has the solar hot water but I don't know anything about them....heat pumps .......well I just learnt a heap thanks to stagg1991

I will wait and see what my power bill is then I may look at some sort of water heating

glad the info is of some help to you!

[Stagg]

Originally Posted by poppa smurf

my son has the solar hot water but I don't know anything about them....heat pumps .......well I just learnt a heap thanks to stagg1991

Just helping us all save money so we can spend more on our toys in the garage!

[poppa smurf]

Originally Posted by Stagg1991

Just helping us all save money so we can spend more on our toys in the garage!

in my case a better equipped caravan!.....maybe a shower and loo

[deesun]

I have a heat pump too, Rheem and only Rheem are allowed to fix it if it breaks down. It was in this house when we bought it. I searched forums for this model and there have been a few probs with them but an upgrade under waranty fixed them. Mine broke down on a thurs night and Rheem unable to get tech out till Mon. They did upgrade and so far so good.

poppa smurf, CEEG panels.

[z80]

Originally Posted by poppa smurf

Z80.....well done, very nice array......can i ask why you didn't have them placed at ground level on stands ?

mine are due to be cleaned again and I'm not looking forward to poncing around on the roof again.

Cows...a beast weighing 800 kilos loves scratching on panels, they just disintegrate...actually tried it some years ago...LOL

Originally Posted by poppa smurf

given the choice I would have mine on the ground for ease of access

Let me know where you live?...in 10 minutes I can steal your 20 thousand dollars of beautiful untraceable panels to put on my roof with just a 5mm allen key and number #2 philips screwdriver.

[poppa smurf]

Let me know where you live?...in 10 minutes I can steal your 20 thousand dollars of beautiful untraceable panels to put on my roof with just a 5mm allen key and number #2 philips screwdriver. [/QUOTE]


happening around the gulf already....port lincoln is a hot spot

we had ours installed with you beaut fixings.....supposedly thief proof

[davenl5l]

well i too learnt something about heat pumps good to know was thinking of going that way but am yet to do research. still getting my head around the cost of solar and which way to go got around $2,500 cash in the budget which will get me a 1.52kw system installed(in country sa .yorke penninsular 2 storey house) but now i am considering going bigger with the rest of the cost interest free average usage is 15kwh per day bill has just jumped to $360 per qtr up from $310 wich is making the budget tuff and i know its only going to go up

[dave351cid]

today i got my first power acc that has had the solar meter going for the full 3 month period.


over 91 days
i purchased 422kwh from the network grid at a cost of $122.23 = ($0.2069 kwh)
i exported 210kwh into the grid at a credit of $92.40 = ( $0.44 kwh)
balance to pay = $29.83.

the same 3 month period last year before fitting the solar i used 5.3kwh per day, this period i used 4.6kwh per day . thats what is going through the meter, what i use during the day while the solar is exporting will be on top of that figure as its used before it gets to the meter and is free power. ( i think some states are metered differently) i recon i am using more power now then i was this time last year. so my 2.1 kw sysyem is has almost cancelled out my power bill. still have the option to add more panels to bring it up to a 3.4kw system.

[mickbundy]

Yeah being single and not using a lot have put in a 1.5 unit and solar hot water to get rid of gas ans am running around $700 in credit for power and gas bills have dropped from around a $120 to 30 so all good here