Do you have solar panels?

[qldfrog]

I understand you dilemma; the installer can make a difference but unless really lame, the real difference will be the hardware: panels and inverter
my own thoughts after a similar experience are: what is the $ difference:
usually a few thousands; it means that the cheap system will be fully repaid within 5 years or so;
This will add up to requiring five extra years for the "better" system (taking into account the yearly interest you do not get or extra mortgage you will need to pay)..well I am not ready to take that bet;

I went for the cheaper provider and the installation was actually better than I hoped, very well done and nice/clean ("solar consultants" here in Brisbane);
actual output perfect and as expected after the first few months;
Just have to wait to see for the longevity of the inverter; I do not worry too much for the panel as they are all relatively similar /mad in china

 

[Logique]

...Bottom line - is an installer like Marks, or Leesons who have plenty of good feedbak worth paying close to seven grand for, when a "budget" type installer like True Value advertise well under $3000. We're in Melbourne FWIW...(disclaimer: I'm a long suffering Bomber supporter who recently noticed TVal's sponsorship but don't hold that against me, be kind)..

Hi, your query is best answered by Victorians, since FIT arrangements seem to vary by state. The Mark Gp price seems reasonable for a system that size. What is your desired $ payback period and risk tolerance for system failure?

Do you really need a system that large, especially if the FIT is low or winding down, since you have gas hot water and a wood heater? New, more efficient technologies are coming, do you want to be stuck paying off old technology.

If it was in NSW (currently zero Net FIT), I'd say reduce to a 2kW system, and select the 'best cheapest' supplier, but if you've got a big roof, get an inverter capable of handling system expansion.

Can't help you on the Bombers, recommend a strong pre-season, but ease up on the in-season sessions.

Cheers L.

 

[Smurf1976]

I can't comment on Melbourne installers (I'm in Tas) but the main issues to consider (listed in random order) are:

1. Quality of the inverter being used.

2. Is the panel mounting system properly secured to the roof and rated for your wind conditions?

3. Does the installer sort everything out with the electricity company? Or do you have to sort this out yourself?

4. Is the installer Clean Energy Council accredited? And are they licensed to do electrical work by your state electrical licensing authority? (Note that these two things are completely different).

5. Is the design of the system, in terms of string voltages and current ratings, compatible with the inverter?

Will the VOC (Voltage Open Circuit - the maximum voltage reached under no load conditions) of any panel string exceed the inverter's input voltage limit on a cold morning if there's no load (eg if there's a mains power failure)? Failure to get this one right could lead to something going "bang" unexpectedly, and errors here are alarmingly common.

What is the inverter's MPPT (Maximum Power Point Tracker - think of it being a bit like how a constantly variable transmission on a car works) operating range? And what is the nominal maximum power point voltage of the panel string? Are they compatible? Get this one wrong and the output of the system will be poor (or even zero).

If there is more than one string of panels, which is almost certain for a system of that size, then are they identical in terms of orientation, panel number etc? If not then does the inverter have multiple MPPT's?

6. Do you have any shading of the panels? Antennas? Power lines? Vent pipes for the toilet? Chimneys / flues? Trees? Anything else? Even a tiny bit of shade on one panel in a string will drop the output seriously - you want NO shade if at all possible.

7. What is the orientation of the roof face the system will be installed on? Is it at least facing somewhere sort of north? It doesn't need to be spot on, but you don't want it facing south (and yes, I've seen this done!).

8. Where will the inverter be located? Avoid putting it on a wall which faces the same direction as the panels if possible. Heat isn't good for electronics that's a given, and the inverter will also generate some of its' own heat during operation. A still day, full sun on the panels and full sun on the inverter is a nasty combination - it'll reduce the output of power almost certainly, and will age the electronics unnecessarily as well. At least put it at a different orientation, better still somewhere not in the sun (mine are under the house).

9. Will you be given a copy of the Certificate of Electrical Compliance (or similar, the exact terminology varies between states)? If not then why not? It's a legal requirement that they give it to you, but one that is often ignored by anyone wanting to avoid electrical inspectors and other forms of scrutiny.

10. What is the basis of the pricing? Will there be any further costs, for example for the meter changeover?

Happy to help with this and hopefully the above doesn't sound too daunting. It's more a "sort the duds from the ones who know what they're on about" type of list. The installer should be able to easily answer all those questions however, and you can sort the ones about shade etc yourself. There's probably a few things I've forgotten to list, but those are the ones that come to mind right now.

In terms of output, at least 1200 kWh per annum for each KW of installed capacity in a reasonably located (not perfect) system would be considered normal in Hobart. Since Melbourne gets a bit more sun, you should get a bit more than that but the difference between Vic and Tas isn't huge as long as we're talking about cities and major towns. Obviously output will be a lot lower if you're at the bottom of a valley etc.

 

[stacks]

I've bought a house with a 3.2 Kw system already installed in QLD, 2 adults, one child. Average about $150 rebate per qtr, differs with seasons. No gas all electric, no real changes in behaviour, Sunny Boy inverter works great. Seems like it would have been a no brainer to install before the rebates ran out given the current and future electricity costs. Interesting to see what happens in the distant future (I hope) with feed in tariffs

 

[pixel]

fwiw, I live in Perth and installed a 1KW system 3 years ago, expandable to 2KW.
We are in a similar situation: small Unit, just the two of us.

We chose Solargain: not the cheapest, but at the time, we considered them the most knowledgeable and "complete" provider. They dealt with all the red tape and showed us evidence of their and their Contractor's licenses. They also gave us the options between different panels (and prices) and as much as I could check online, their claims and explanations were pretty accurate.

I understand that Solargain are a franchise; therefore, we may have been lucky with our local outfit. I do believe though, they're also operating in Melbourne. Might be worth checking them out.

18 months later, we upgraded to 2KW; at that time, WA had finally introduced a 40c FIT, which was guaranteed for ten years. (It was soon after reduced for new installations, but existing contracts will be honoured.)

Our roof pitch is about 30 degrees, and the panels are facing North-East. There is no shade on any of the panels. Our inverter is branded "Orion"; Made in China of course, but by all reports of a reliable quality. Ours is installed under the carport roof at eye level. That way, it's protected from the elements, and is easily checked.

After almost three years in operation, our total production has recently exceeded 7MWh. In the first year, we got 1,666 KWh from the 1KW system. Predictably, this has about doubled after the upgrade. See table below. (Note: Averages after the upgrade are calculated as from that day.)



PS: Our power bills have gone into Credit; even after this year's hot summer and very cold winter mornings, with RC Aircon running long hours, the 2KW system has kept our annual power bill below zero.

 

[stewiejp]

Hi, your query is best answered by Victorians, since FIT arrangements seem to vary by state. The Mark Gp price seems reasonable for a system that size. What is your desired $ payback period and risk tolerance for system failure?

Do you really need a system that large, especially if the FIT is low or winding down, since you have gas hot water and a wood heater? New, more efficient technologies are coming, do you want to be stuck paying off old technology.

If it was in NSW (currently zero Net FIT), I'd say reduce to a 2kW system, and select the 'best cheapest' supplier, but if you've got a big roof, get an inverter capable of handling system expansion.

Can't help you on the Bombers, recommend a strong pre-season, but ease up on the in-season sessions.

Cheers L.

Thanks mate -

Payback period - IF the cheap mob are right (TruVal), we should regain the outlay in a few years. The more expensive (Mark) probably 5 or 6. Hence the conundrum. Will phone the cheap mob this week and see what they have to say.

A system that large (been looking at around 4kw) - *seems* to be the best value for money for our situation, still looking at other options as well. It should be said that we do use the air conditioner a bit during summer, and when the missus can't be bothered lighting the fire. Or we run out of wood.

FIT's - I'm actually budgeting for this to never actually return any money. If it does then great (or in our case since we are with the same supplier for gas we will then get a discount on that as an alternative too) but for budgeting purposes we're simply aiming to kill or significantly reduce our electricity bill.

As far as getting a bigger inverter to cover expansion - it is/was something we've been looking at, but the last salesman we saw (Marks) said this wouldn't work, as the sum of the watts on the panels (eg 200W) multiplied by the number should reach as close as possible to the inverter size. If it was say half, it just wouldn't work. Not saying I trust that, which is why we're still looking around.

Thanks for the advice, will take it all on board

 

[stewiejp]

Smurf,
thanks for the detailed reply...

Quality - apart from the cheap company (True Value) all other parts we are looking at are top of the range, or close to it, and installed will 100% guarantee. Will speak to TV soon. The expensive group do all the arranging with the power company on our behalf, although if saviing a few hundred or thousand dollars means I have to do it, am more than willing to do a bit of running around.

5. Is the design of the system, in terms of string voltages and current ratings, compatible with the inverter?
- I certainly hope so... something to look at, and I suspect the reason True Value are so cheap.

Shade - none at all, we're lucky. (Have been having a look at odd times of the day since we came up with this idea)

Inverter - I guess it would go under the pergola - not far from the panels. Panels all face north.

Meter changeover will be billed separately from the power company. They arrange it but we pay if. All other compliance certificates etc included and covered, including independant inspection.

It's more a "sort the duds from the ones who know what they're on about"
- exactly what we're trying to do.

Thanks again, you've given us some ammo for the salespeople...

 

[Logique]

Stewie, a too-large inverter does mean reduced efficiency. But since you're planning quite a big system to begin with, you may as well match the inverter size to the panel capacity as Mark said.

The other thing is, do the various installer companies offer the same panel failure warranties, and will these companies be around in 25 years time to make good on their promise.

Connecting to the grid: I engaged my own Level 2 electrician because I knew he was good. You don't necessarily have to get the solar panel company do this for you (not in NSW anyway).

 

[pixel]

FIT's - I'm actually budgeting for this to never actually return any money. If it does then great (or in our case since we are with the same supplier for gas we will then get a discount on that as an alternative too) but for budgeting purposes we're simply aiming to kill or significantly reduce our electricity bill.

As far as getting a bigger inverter to cover expansion - it is/was something we've been looking at, but the last salesman we saw (Marks) said this wouldn't work, as the sum of the watts on the panels (eg 200W) multiplied by the number should reach as close as possible to the inverter size. If it was say half, it just wouldn't work. Not saying I trust that, which is why we're still looking around.

Thanks for the advice, will take it all on board

We didn't count on the FITs either, but find they help quite a bit

As regards Marks' assertion about inverter size, have a look at the data I provided yesterday:
average 4.5 units per day from 1KW with a 2KW inverter; twice that from 2KW using the same inverter.

Note: The average over 18 months was 4.9 u/d, but that included a second summer when production is naturally higher.

 

[stewiejp]

Thanks guys,

Pixel - so a 4.2 inverter with only 1600 watts worth of panels (8x200) will still be worthwhile? And obviosly upgradable if needed. That's the cheapest option, or one of the better deals anyway here for $2600:http://www.truevaluesolar.com.au/products/specials/

Your data above looks like in my situation I could do exactly the same. Will call them tomorrow and see what they have to say for themselves. The inverters they mention on their website are good ones, however no mention of what panels they use (alarm bells?)

Thanks again everyone.

 

[sptrawler]

I just checked the output on my 1.5Kw Sharp system. 20 August 2011 to 20 August 2012, 2500kw/hr produced 1400 exported. Located in Perth, north facing.

 

[Smurf1976]

As far as getting a bigger inverter to cover expansion - it is/was something we've been looking at, but the last salesman we saw (Marks) said this wouldn't work, as the sum of the watts on the panels (eg 200W) multiplied by the number should reach as close as possible to the inverter size. If it was say half, it just wouldn't work. Not saying I trust that, which is why we're still looking around.

Whether or not it will work depends on the string voltage, not the power rating, being sufficient.

For example, suppose that your inverter has an MPPT operating range of 140 to 340 V and a maximum voltage of 400 V. Exact ratings will vary, but this is the actual specs of one inverter that was popular a while ago.

Now let's assume that you will be using nominal 24 volt panels. These actually have an open circuit (VOC) voltage of around 44.1 (will vary a bit with temperature) and a peak power output somewhere around 35 V (will vary significantly with temperature and the MPPT will follow this change to maintain maximum output).

Now, if you connect 4 panels to this inverter then it might, if you are lucky, actually turn on. It certainly won't work too well, since half the time the optimum voltage of the string will be below 140V. That's an example of a dud design.

In the real world, this inverter would be ideally suited to 8 panels (VOC 353 and maximum power at about 280V) but will work fine with 7 or 6 panels. 5 would be pushing the limits however, and I wouldn't recommend that for a "generic" design without first checking the specs of the actual panels in question. Even then, it's pushing it a bit far.

If you used a 5 KW inverter with a maximum input VOC of 500 V and configured the panels into two strings, then using 24V 250W panels (the second cheapest size per unit of output and easily obtainable) then you could realistically install anything from 1.5 to 5 kW without problems. There's a few technical considerations as to the actual wiring, but it's certainly very doable.

Another thing to consider is overpowering of inverters which, depending on design and circumstances, may be a viable option. In short, since you will rarely hit peak output, there's no economic justification for having a 2kW inverter on a 2kW system for those rare occasions when it will actually reach 2kW. It's more sensible to use a 1.6 kW inverter (cheaper) or to put 2.5 kW of panels on the 2kW inverter (saving cost per unit of output) instead.

The main proviso here is that you're using an inverter which will self limit its' actual output based on software settings, so as not to overheat itself. There are units designed to operate like this (notably the SMA inverters) and others which won't cope even briefly.

In my case I'm running two separate 1.1kW inverters. One has 1.36 kW of panels on it, the other has 1.52 kW. I did it this way for purely economic reasons, the aim being to produce energy at the lowest price per kWh. There's nothing "wrong" with any of that, and the underlying principles are much the same as those which underly much larger electrical things, including run-of-river hydro schemes and wind farms. Both inverters cap their output to 1100W as set by software.

Production from the 1.36 kW system last financial year was 1636 kWh. Panels are at 22 degree pitch, facing 20 degrees West of true North. This system was installed in two stages, initially to 1.02 kW. Panels are 170W each.

Production from the 1.52 kW system, which has been operating less than a year, is expected to be about 1400 kWh per annum. Panels are at 30 degree pitch, 70 degrees East of true North. This system was installed in a single stage, and uses 190W panels.

There is zero shading on either system.

So far as energy consumption is concerned, hot water is heat pump on off-peak tariff, cooktop is gas, oven is electric. The heating is a bit more complex, but it's electric and wood in the main part of the house, and wood and oil downstairs.

 

[pixel]

Thanks guys,

Pixel - so a 4.2 inverter with only 1600 watts worth of panels (8x200) will still be worthwhile? And obviosly upgradable if needed. That's the cheapest option, or one of the better deals anyway here for $2600:http://www.truevaluesolar.com.au/products/specials/

Your data above looks like in my situation I could do exactly the same. Will call them tomorrow and see what they have to say for themselves. The inverters they mention on their website are good ones, however no mention of what panels they use (alarm bells?)

Thanks again everyone.

You can Google a few answers online.
That's what I did - and found that the Orion inverter was considered good quality.
You may also want to check the difference between mono-crystalline and poly-crystalline panels.
No, I'm not an expert, so I won't give you an assurance. But we picked the better quality panels; and our output, 1666 units from 1KW, with roof not even straight North, matches exactly sptrawler's 2500 units straight North from 1.5KW.
How much we export will of course depend on our usage pattern; also on the type of our appliances. As an example, I noticed a significant drop in power consumption when I - "Finally!" the wife said - replaced the old CRT LG TV by a new LED LCD Samsung.

 

[stewiejp]

I - "Finally!" the wife said - replaced the old CRT LG TV by a new LED LCD Samsung.

LOL - I got a similar reaction when we first "discovered" the new telly.

We're getting to the pointy end of things now - have decided a 3kW system will do the job nicely. Trina (or similar) 250W panels (x12), and a good 3kW (SunnyBoy/Auora etc) inverter will fit nicely on our roof. Since the house isn't huge, and luckily our biggest bit of roof faces north with no shadows - 12 panels will fit nicely we may as well get the better ones.

At least we know what we are after now when negotiating with the suppliers. The look on the Marks Group salesman's face when we asked for a discount for cash was priceless! (He was trying to sell us finance I think..)

 

[Logique]

Hey well done Stewie, you're on your way.

 

[numbercruncher]

Someguy on the news gloating how " the money rolls in " , making 6k a year from a roof full of solar panels while the average house elec bills are up $60 a year , obviously households are subsidising this gravy train for people.....

Another poorly thought out system ?

I understand kw government payments are being slashed from 50 odd cents to 8 , so probably put the electricity farmers off for a bit ?

 

[Calliope]

Someguy on the news gloating how " the money rolls in " , making 6k a year from a roof full of solar panels while the average house elec bills are up $60 a year , obviously households are subsidising this gravy train for people.....

Another poorly thought out system ?

I understand kw government payments are being slashed from 50 odd cents to 8 , so probably put the electricity farmers off for a bit ?

Yes , I would like to see the gloat removed from his face. Unfortunately it's not going to happen. In Queensland;

Energy Minister Mark McArdle yesterday announced changes which will see the rebate for new installations reduced from 44 cents per kW/h to just 8 cents per kW/h.

Although existing owners will retain the generous rebate until 2028, from July 10, anyone who sells their house with solar panels will lose the 44 cents per kW/h rebate and new owners will get the lower rate.

http://www.couriermail.com.au/news/...e-to-maintain-it/story-e6freoof-1226408292697

 

[stewiejp]

As mentioned I am not all that interested in the FIT's, basically because I am very sceptical of government "schemes" to get people to move in a "green' direction - remember the insullation debarcle, same government.

The main thing we are looking at is a return on investment (discounting FIT's other than putting our account into credit when the sun is shining to make up for winter.) Eg. If we pay (in round figures) $6000 for a system, and it reduces our $1200 annual bill to zero - that's a 20% return annually. Taking into account the savings are tax free, it equates to a 30% (or more) ROI. OK, it will cost a bit more that $6k and our annual bill is likely to be in future more than 1200 but I think you get my drift...

I'm just throwing figures around, but it *seems* after we jump through a few hoops, outlay some cash and wait for the sparkies to do their thing, (probably take months, the electric suppliers are't going to be in a rush to "re programme our "smart" meter if it costs them $$) - we could be looking at a great investment. Along the same benefit of *not* signing up to 20% credit cards, hire purchases etc...

 

[prawn_86]

Along the same benefit of *not* signing up to 20% credit cards, hire purchases etc...

Or prepaying private health before the end of last FY. Not essential so to speak, but in theory delivers greater (relatively) risk free returns than cash in the bank

 

[drsmith]

The main thing we are looking at is a return on investment (discounting FIT's other than putting our account into credit when the sun is shining to make up for winter.) Eg. If we pay (in round figures) $6000 for a system, and it reduces our $1200 annual bill to zero - that's a 20% return annually. Taking into account the savings are tax free, it equates to a 30% (or more) ROI. OK, it will cost a bit more that $6k and our annual bill is likely to be in future more than 1200 but I think you get my drift..

.
Any calculation of ROI needs to take into account the hardware itself does not have an infinite life and is therefore a depreciating asset.

To me, the minimum aim should be to recover the initial cost of the investment plus associated opportunity cost within the shortest warranty period of the associated components. Even then, the investment is not entirely risk free.