All things Solar (merged threads)

[zilo]

Originally Posted by ute83

Here in Victoria the feed in tariff stays with the residence, so yes.

are you absolutely sure about that?

[zilo]

.double post

[zilo]

Originally Posted by AlanD

Hi Zilo,

Your 10 panels should (will) produce about 350 Volts DC. (Somewhere I have a spec sheet for the panels on our roof that, from memory, produce approximately 40 volts d.c. open circuit, this falls a bit when the load comes on.

The heater in your storage tank will have an insulation rating for 240 V a.c. which means it is able to withstand potentials of 340 volts or there-abouts. So they ought to be OK for the nominal 350 V d.c. (There is always some "safety" headroom in the design). But of more concern is that the (usual) heater element is designed for 240 volts and so will (try) to draw a larger current than its rating. This is likely to be inexcess of the panel's capability and there will be heating effects in the panel for which they are not designed. If you limit the panel string to 6 or 7 panels you should avoid this problem. This would provide 1500/1750 watts if you are using the more modern 250 watt panels.

Another problem will be with your thermostat contacts which are designed for a.c. and any arc that gets drawn when the contacts open is extinguished when the voltage waveform passes through zero volts. With d.c. this does not happen and thus any arc is maintained. This causes rapid erosion of the thermostat contacts and failure. One failure mode is that the contacts get welded closed and thus heating continues until some other fault appears. This might be, if the storage container is a pressure vessel, rupturing of the tank because the increasing water temperature causes expansion and thus increased pressure. Very hot water can also be a real hazard to people, especially if they are not expecting the very high temperatures. Particularly at risk are young children in baths who turn on a hot tap. d.c. thermostats are available, I believe, and I would counsel that you retro fit one of these if you proceed with your plan to directly feed the heater element from the panels.

Incidentally, this arcing business is the reason why you should always start the isolation procedure for a PV grid tied system by opening the a.c. switch or miniature circuit breaker on the output side of the inverter. This causes the input current to the inverter to drop to zero and thus no risk of arcing when the d.c. isolator(s) are opened.

Cheers

Thanks for the reply Alan.

I hooked it up and it worked.
I used 24 panels in a series parallel combo to get the impedance of the panels (9 ohms each) to match the element resistance (15 ohms).

The arcing of the switch is easily overcome with a capacitor across the contacts, same as we do in ignition systems for cars.

Anyway it didn't take long for the water to heat up, I tweaked it down to 50 degrees temp and it switched off when it got to that temperature.

One could use the thermostat contacts to drive a much sturdier set of contacts to mitigate the problem you describe...or a fuse...


In any event I have decided to go a different way...I am going to use my SMA5000TL inverters from my former residence in off grid mode.

The kind people at SMA give you a passcode to get into the settings to disable the anti-islanding option.

So...my grid inverters from former residence can now act in standalone mode....no need for charge controllers etc.

Of course it requires a controller to fool the GIA's into thinking they are on a grid....and missus will need to do washing etc during the day now...

That's where the Sunny Island unit comes in, it handles multiple grid inverters forming it's own little grid.
This is a SERIOUSLY good bit of gear, I would even consider this in the suburbs to charge batteries off peak for peak use...


It will control power directly to the electric hot water element with parameters like...only when batteries charged...only during certain hours etc etc etc


Decided to go that way to save on building custom stuff...and more stuff


Anyway...convection solar is a dinosaur in my opinion now.

[LG17]

Originally Posted by poppa smurf

yes but given the angle of the sun it is producing little,........I produced 6 KW's yesterday.

not enough to cover my usage, winter is coming and along with the increase in supply charge and a slightly higher tariff charge I think I will begin to chew into my credit for a while.

I'm just under 17Kw today so far.

[ute83]

Originally Posted by zilo

are you absolutely sure about that?

Yes.

http://www.energyandresources.vic.go...ng-eligibility


Anything else Z80.

[poppa smurf]

Originally Posted by ute83

Yes.

http://www.energyandresources.vic.go...ng-eligibility

a lot of good info in that link, thanks for that, I will be able to pass on a bit more now.

[buggerlugs]

Mines has come good again. After finding the buggered fuse and fixing it $580 power bill, $840 credit. Happy days...............

[zilo]

Originally Posted by ute83

Yes.

http://www.energyandresources.vic.go...ng-eligibility


Anything else Z80.

We were buuying a place just two months ago and were told completely contradictory advice to yours by both the owner and the real estate agent.

[Auslandau]

Well ..... had the panels installed and turned on pretty much 1st of January this year. Have been waiting for a power bill since then, seeing that one wasn't forthcoming, rang them up to ask whats happening! Got an apology and reveived a bill a few days later ...... finally!!!!!!

Finally received our first power bill since installing the 3kw system. Last bill before solar, $780 with just over 2000kwh. This power bill with a 3kwh system installed (estimated 12-14kwh per day average) ......... $760 with just on 2000kwh used.

Nearly fell over!

Day before solar, 31 cents, day after solar installed 39 cents, rebate from government - 8 cents. On this basis I will pay the system off in 2,324,222,123,232,675,649 years.

Apparently made 512 kwh's rebate of a grand total of $41.00 rebate. Increase in levy for solar .08 cents = $41.00

WTF am I missing here?

Rang them ....... Was told the bill is correct. I said why did I spend 4k on solar for zero savings? She said .... "I dont know why ... at least you are saving the environment!" I said thanks for your help. Hung up, rang again and got someone else who had a 'proper' look and said that it looks very wrong and the code says that I haven't had a reading and was an estimate. She cancelled the bill and now waiting for a reading and another bill.

Sooooooo ........ what am I missing? Did I stuff up and should have not put solar in? I dont expect credit, it is a 12 panel system and over summer it averaged around 12-14 per day. I do expect to be in front a little but am a bit confused at the moment on what is going on and what I should be expecting when I finally, one day, receive the right bill.

[CJR09]

were there any extraordinary circumstances with your install? I would have thought that 12/14kw pretty average for a 3kw system in your neck of the woods?

an optimized setup orientation etc should yield closer to 17/18

even so you will be generating close to 55% of consumption yearly average? - biggest factor will be your time of use day/evening/night

clearly the second person you spoke with is correct and first reading was an estimate and you should expect to see difference with actual read - can you take the read yourself and phone it in?

[Auslandau]

I could have if she asked but said they will sort it out very quickly. Worried though its coming into 6 months now and no bill this year .... apart from this one which was cancelled.

The estimate I put up was a very rough guess. I was getting 18kwh per day often but some were lower and just estimated a conservative average for the 4 months. Could possibly be a higher average.

[zilo]

Originally Posted by Auslandau

I could have if she asked but said they will sort it out very quickly. Worried though its coming into 6 months now and no bill this year .... apart from this one which was cancelled.

The estimate I put up was a very rough guess. I was getting 18kwh per day often but some were lower and just estimated a conservative average for the 4 months. Could possibly be a higher average.

Doesn't it annoy you that they put the price of power you draw off the grid up by 8c a kw after you put panels on the roof?

It's a big scam.

[Auslandau]

....... I used the word 'rort' about 14 times to the first lady on the phone. She really had nothing to come back with after a while.

[Cashie]

Why don't you go and look at your meter and compare it to your bill?
Would quickly prove if the reading is correct, pretty disturbing that's for sure.

[ebxr8240]

Is it worth fitting solar before rebates are cancelled ??
For me .. That is..

[zilo]

Originally Posted by Auslandau

....... I used the word 'rort' about 14 times to the first lady on the phone. She really had nothing to come back with after a while.

go straight to the ombudsman.

[poppa smurf]

sounds very much like an estimate.....this is one reason why I take my own readings.

your account should be cut in half with the 3 KW solar input, something is very wrong here.

unfortunately we "generators" pay a premium for our input to the grid.

I too would be seeking out a "greater" power.

[ute83]

Originally Posted by Auslandau

....... I used the word 'rort' about 14 times to the first lady on the phone. She really had nothing to come back with after a while.

You need to shop around for the best deal. The best deal I got was from a Tasmanian power company.

[Auslandau]

WIll start shopping around ...... just sitting here patiently waiting for the bill to arrive

[GasoLane]

Originally Posted by Auslandau

WIll start shopping around ...... just sitting here patiently waiting for the bill to arrive

The bill shouldn't be a problem, remember a previous thread, you're a small business owner.

You've got HEAPS of money just lying around

[xisled]

The problem with the smart meters in Victoria is that the readings on the meter are different to what’s on the invoice.

All 3 retailers I have worked for receive the readings based on the usage and consumption, not continues meter readings like the old style meters. So when you receive your invoice, all that would be on it is opening read 0 closing read 500kHw. The reason for this is that the distributor no longer reads the meter as a continues reading as most smart meter data is sent to the distributor on a 30 minute basis.

So looking at a smart meter, will not match your invoice.

In Victoria and I’m guessing other states, the problem is that most of the retailer have been around before solar was big and due to this, the software they use to produce invoices, cost massive amounts of money to update for solar.

Also currently a couple of the distributes in Victoria are having massive problems with sending correct readings to retailers. This is causing massive problems with all retailers and delays in sending invoices out.

[buggerlugs]

http://www.couriermail.com.au/news/q...age%7Chomepage

[LG17]

Typical Courier Mail - have to log in and probably pay to read the article... :(

[Cashie]

Got a question for your solar dudes...
I'm on acreage with 3 phase power and a 3.5kw system with a SMA 5000TL 3 phase invertor.
System works well, I was getting about 22/23 kW a day in summer.
But, as I am in WA on the 8c feed-in tariff, I want an easy way to know when I am not using my produced power (ie exporting to the grid).
As mentioned, I'm on acreage, so my power meter is in a box at the boundary a distance from the house and not easy to check at a glance.
I'd like to have a basic device that at a glance can tell me if I'm exporting (and therefore should be using the dishwasher or washing machine etc)..
I can monitor my SMA with bluetooth but of course this just tells me my production.
Anything out there that is fairly cheap and can do this?

[poppa smurf]

only this http://www.sma-australia.com.au/en_A...ebconnect.html

that I'm aware of, some inverters come out with the necessary software, some didn't.......dont know of anything else.

[EgoFG]

I use a 3ph Wattson Meter for just that - it is independent of most things - it has an inductive pickup on each phase and on the solar input line.

[Cashie]

Originally Posted by EgoFG

I use a 3ph Wattson Meter for just that - it is independent of most things - it has an inductive pickup on each phase and on the solar input line.

I was thinking something like this might be the go, do you have any more details on your setup?

[Auslandau]

Originally Posted by GasOLane

The bill shouldn't be a problem, remember a previous thread, you're a small business owner.

You've got HEAPS of money just lying around

Thats right!!! I did it all for charity and for the good of mother earth .......

[Sam_Boss260]

Quick question....
Got two quotes. Same ballpark in price. One is using a Delta inverter the other SMA inverter.

Is one better than the other?

[Cashie]

Originally Posted by Sam_Boss260

Quick question....
Got two quotes. Same ballpark in price. One is using a Delta inverter the other SMA inverter.

Is one better than the other?

I'd go the SMA (and I did with my setup).