Thread: Solar power

Hi Bob,

Neither of the systems that you have listed have the details of the panels.

In relation to which system will work better for you it is clear that you are only going to be on the $0.08/kwh export rate. As such to get best return on investment your system should be sized to match your daytime usage. It is already known that you are using 31kwh/day which would be the same with either system. It may be worth over the next few days to check your meter morning and night to track how much power you are using during the daylight hours when your solar system will be supplying your power.

If you find that you are only using 15kwh during the daylight hours, then the 5kw system (averaging 20kwh/day) should come close to covering your daytime use (for the sake of the argument you will be selling 5kwh at the $0.08/kwh export rate. Paying the extra for the 6kw system (averaging 24kwh/day) you will still be drawing off your 15kwh during the daylight hours, but you will be selling more at the $0.08/kwh export rate (9kwh). As you are only going to be able to sell your extra power at the $0.08/kwh export rate, you may find that it takes a lot longer to get your return on investment from the 6kw system over the 5kw system. Obviously these figures are just made up which is why it is good to monitor your use for a few days.

All that being said there are going to be some days where your system will not be able to cover your daytime usage despite the best intentions of all of the modelling and estimations. When that is the case the bigger system will still produce more than the smaller system and will come closer to matching your daytime use, even on poor days. In my view if the extra few $'s isn't going to break the bank I would be going for the bigger system just to help out on the not so perfect days, obviously this is within reason and I wouldn't suggest going silly chasing 10kw. In retrospect, despite sizing my system to cover the average use over the year, considering I have had a few less than perfect summer days with my system so far I wouldn't have minded another kw as I feel it will be a hard grind over the winter. Whilst on average across the year it may work out, it still hurts having a dip down from a 13kwh/day average in summer to having a bad single 3kwh/day.

Hello,

Any traps with solar power ie I have somehow got the idea in my head that if you have solar power and you also need to use some from the grid as well then you go onto a more expensive grid rate and something else about different off peak rates ?

Is that right or just myth ?

If there is any truth in the above then that too should be factored in to any calculations regarding payback times and costs.

Bill

Originally Posted by steamingbill

Hello,

Any traps with solar power ie I have somehow got the idea in my head that if you have solar power and you also need to use some from the grid as well then you go onto a more expensive grid rate and something else about different off peak rates ?

Is that right or just myth ?

If there is any truth in the above then that too should be factored in to any calculations regarding payback times and costs.

Bill

Unless you have battery storage you will still be drawing from the grid when the sun is down. I don't think that there is different rates between not having solar and having solar. When I was going through my set up my retailer asked me to call them to talk about new plans. In the end my plan with solar was the same as without. Our provider do offer a % discount off each bill if you sign up with them for 3 years, this wasn't available with solar. They only offered a pay on time discount, however there is no contract so you are free to swap retailers at any point. Before solar we only got the pay on time discount as we didn't want to sign up for the 3 year contact, which is why we are getting the same with solar as without.

It is a good point however and worth putting a call into the retailer to see what they have on offer.

I apologize, up front, for not reading all the posts in this thread.

I have and use a solar power back-up system in my house as we can have power grid failures which last from a blink of an eye to 8 hours. One Sunday, the girls in the grocery store quit counting after 60 (that's sixty) power failures in one day.

It is winter here. I require 500W to drive the motors in my central heating compressed wood pellet stove. I can do that for 12+hrs. Thank goodness.

What, exactly are you after? At the end of the day, it is the storage, the batteries, that make your day and night comfortable.

I am no "greenie" who has the hots to get off the grid. I expect a modest supply of electicity at all times. I have had little choice but to make that happen for myself.
With 4 x 6VDC deep cycle batteries ganged together ( 2 x 6, x 2 = 12) I can give the finger to the system if and when I have to. I'm not the least bit happy that this was necessary. But. In the past 10 years, nobody has or can prove me wrong.

Originally Posted by Robson Valley

I apologize, up front, for not reading all the posts in this thread.

If you had read them you would know you've been here before.

Originally Posted by Robson Valley

At the end of the day, it is the storage, the batteries, that make your day and night comfortable.

As stated earlier
https://www.woodworkforums.com/f271/s...3/#post1614346

"As I understand it these systems can't island** so they wouldnt solve your problems anyway.

**its not that it cant be done. I believe islanding has been excluded from the subsidies.(anyone?)"

Stuart

Originally Posted by Sir Stinkalot

Hi Bob,

Neither of the systems that you have listed have the details of the panels.

Sorry Stinky
The panels are ET-M660250

They have a good reputation, but no doubt other better panels can also be had -- for a price.

Here is a short discussion on them.
(hippiesparx works for Positronics)

An update on this subject.

We finally went with Positronics 6Kw system with a Trannergy inverter.

I have been stuffing around with this for ages now and decided that I needed to do something, so I asked Positronics for a new quote. Here is their reply to that request.



Hi Bob,Good to hear from you… it's been a while but waiting has worked in your favour as prices have dropped and the STC price has increased meaning we're now able to do the 6kW Trannergy for is $7999 and add an extra $1000 if you still want an SMA. In regards to your gas hot water what we are doing which is popular is adding a timer to a regular electric hot water system and running it off T11. This works out to be a much cheaper option for several reasons. Firstly it's low tech no plumbing on your roof to leak or regular maintance on something you can't easily check on. Also everyone does electric hot water so the competition on price is better. Bunnings Masters do them as well.


Looking at the photos again I would do the following..
Relocate sub board to the the main meter box to allow for expansion for an electric hot water circuit our electricians can run the new circuit during the upgrade and have it ready for the plumber saving you some money. Or if you are handy which I believe you are you can plumb it in yourself and our guys can wire it up. Then put the electric hot water on a timer that will be powered by your solar. You then have control over the amount of heating you give the system and when not the power companies. Rheem also have a dual element unit that allows the connection of peak and off peak tariff in the one unit.



The other bonus is the new 250w panels are flash testing at 260w so on a 6kW system it like having an extra panel for free.
Give me a call to discuss further I've attached a new quote for the Trannergy and the SMA. The Trannergy has in built data logging to www.pvoutput.org which is now done via a Ethernet over Power plug pack.


Let me know your thoughts and feel free to give me a call anytime.
Cheers
Rick



And here is their new quotation for the 6Kw:

Supply and Install 6.00kW of ET-M660250 and a Trannergy PVI5400TL inverter $11,217.00
Due to AS5033 external Air Con. type duct will be used to house cable to inverter/meter
Meterbox Upgrade sub board relocate $250.00
Hotwater Timer and new Circuit to electric HW system $350.00


Single Story Tile
No deposit required. Full payment due on day of install. EFT preferred.

Sub Total $11,817.00
GST $1,181.70
Total Including GST $12,998.70
Less 124 RECs $4,340.00
TOTAL $8,658.70

We took his advice on the hot water system (HWS) and I purchased a 400 litre 3.6Kw HWS which I will plumb in myself. We also decided that the Trannergy inverter he uses seemed to have no major complaints against it; so we went with that too.

The first company that we got a quotation from (Love Energy) wanted a large deposit in advance. That company has since gone bust so that may well have been a lucky escape.

I have nothing but praise for the people from Positronics and would not hesitate to recommend them to anyone.
My house originally had a paltry 40 Amps of capacity at the main switch board, so I asked Positronic if they could increase this to 80 amps. (I had recently been quoted by another electrician a figure of about $2k for doing this.) They said sure, no problem but they would need to purchase some extra big cable for doing this and is that OK.
I agreed to the extra cost. When the time came for me to sign off on the job the electrician told me that as they had not had to move the sub board which they had allowed for in the quotation, they would not charge me for the cable as the difference was only about $10 extra for the cable. So, they could have easily charged me another $260 but they didn't.

The output from the system they installed for me can be monitored online here. Clicking on the dates gives output figures in 5 minute increments throughout the day.

Bob, I have read your post and the replies with great interest, as the question of Solar has been on my mind for quite a while, I belong to a Technicians Forum and this subject was discussed in quite some detail.
The main points that are not usually discussed or pointed out by sales people are the efficiency of the panels as a whole when shade covers a panel,; Sir Stinkalot mentioned that point and it is very important.
For that reason I would prefer the panels to be individually controlled, but that really sends up the pricing.
The other points are the quality of the panels and inverters.
It does get a bit overwhelming reading all the facts, but it is good to be well informed,
finally, it all comes down to finance. Thanks for posting your experience, Amos

Qualifier.

I know squat about solar power.

I don't have solar power.

I did get some quotes.

$20K would have got rid of our entire power bill for the year apparently (that was some time back).

Just recently I saw a advert that surprised me.

Does your power bill include electricity for air conditioning?

Is that a big proportion of your annual power cost?

Some bright spark has "invented" solar panels for refrigerated air conditioners just the same as you can have solar panels for your hot water (ala solahart etc).

Don't ask me how it works I have no idea.

The add said the panels have the refrigerant gas pumped thru them and somehow the sun heats the gas and when the compressor compresses the gas you get more cold - and that manes the air con compressor only comes on half as often and uses half the power.

The whole idea being - that you still have solar panels for power generation BUt you also have some for hot water and some for air conditioning.

Apparently this means your saving on power draw to run your air con, and your hot water and the solar energy you do generate takes MORE $ off your power bill annually!

Caught my attention because it seemed to be a smart idea...

Instead of generating solar power to use on a air con - cut the actual demand on the air con with a solar type panel for the air con gas!.

Maybe its just a big con - I have no idea.

No doubt the experts here will know all about the pros and cons of solar hot water and solar air conditioning etc.

I'll leave the real world experience to those who have done it.

To be honest to me it all sounds like white fella magic if you ask me.

Think I'll stick with my MEG.

Cheers

After a few years of hoping the price of solar installation would come down to acceptable levels for us, we finally had a 4.5 kWh system installed in July this year.

Ours is a bit different to all others I have come across so far, we have individual inverters on each panel.

It has been far better than we thought it would be in sunny Melbourne.

Our panels are in 4 banks; 2 banks of 4 on tiled hip roofs, 2 banks of 5 on tilt frames on a flat roof, which incidentally increased the price somewhat over a standard hip style tile roof.

Total installation was $9,600 and for comparison’s sake, if they were all installed without the tilt frames, cost would have been approximately $8,300. If we had gone for a Sunny Boy dual inverter, cost would have been $7,300 in total, including the tilt frames.

I can with some certainty, state that having individual inverters for each panel boosts power output somewhere between 11% to 16%. This figure was obtained empirically by comparing neighbours power generated in our street, and then simply working out the difference per kWh produced for each kW of panels installed.

Currently as of today, yesterday and when we get reasonably full sunny days, we are generating 30 kWh of stuff per day. This is probably pretty much as good as it’s going to be as we are only three weeks from the longest day of the year.

One thing for sure is that on light cloudy bright days, almost all of the panels are within a watt or two of each other. Switch that to a bright as anything sunny day and I can see some reasonable variable power outputs from each panel in the middle of the day and some large power differences outside of the peak power input times.

As I type this we are in the midst of a very light cloudy bright day, the outside thermometer is showing 37.3ºC. The panels themselves on the readout in real time, well around 1 minute time lag, are telling me their temperature is between 52.21ºC to 57.14ºC and we are producing between 4 kWh and 4.3 kWh.

Yesterday with a slightly cooler ambient temperature and full sunshine around 1330hrs when I arrived home, we were pulling around 4.6 kWh for a while. I have seen 4.7 kWh a couple of days ago around 1130hrs but as the temperature raised it pulled back to 4.55 kWh around 1330 hrs. These times are standard Eastern Time, not daylight savings time. Our latitude is 37.56.

As for our power usage and bills, well we are currently in the black on an overall basis since the plant was officially switched on in the first week of August this year. Well to put it into perspective, we were in the red more than less for August, and just into the first week of September, then it turned around.

Since September as a whole month and subsequently each month since, we have become a net exporter of electricity instead of a net consumer.

Our official power rate is $0.08 per kWh, however we received $0.2514 per kWh exported into the grid on our first power bill after becoming a generator. We were at a loss to figure this out, it took some effort to find that we were, in Victoria at least, guaranteed a fair price payment of power generated at the same price we pay for power we import.

As a matter of interest, there is another charge, supply charge it’s called, this is at $0.92 per day and should be factored into any calculations one makes.

We are pretty much over the moon with our system as it is going far better than we thought was possible.

Fitment of inverters to each panel for systems 3 kW or bigger, were approximately 30% more expensive on an apples for apples basis. Systems less than 3 kW the price of systems with inverters for each panel were progressively more expensive as one goes for lower sized systems. These price differences were current in January to April 2013 when we were seriously shopping for a solar PV system.

As we are retired and spend much time home, we are able to take advantage big time of solar input. I do my arc welding when we are producing plenty of power, as well as running other electrical tools in the shed during the sunshine hours. For other obvious reasons we also run the dishwasher late in the mornings (once power input is up) instead of at night after the evening meal. The washing machine is also used pretty much when power is being produced. We have found we can have the dishwasher and clothes washer running at the same time, two computers and background stuff consuming power and still be exporting to the grid, albeit not too much being exported. The dishwasher and clothes washer heat their water, so no drain on our HWS.

Our power imported is now directly related to the weather, within reason.

On the 01.12.2013 we produced 29.96 kWh of power we exported 25 kWh to the grid, we imported 3.0 kWh, own use power that we generated was 4.96 kWh for a total of 7.96 kWh. The actual dollar value goes like this. We exported $6.29, we imported $1.76 we earned $4.53. Normally we would have to pay $2.20 so our total savings for the day was $6.73.

That is a very good day and not a normal day, but it gives an idea of how it can work.

A very bad day is like this; it rained all day. On the 28.11.2013 we produced 3.45 kWh, we exported 0.30 kWh we imported 7.3 kWh, own energy usage was 3.15 kWh total usage 10.45 kWh. Money wise it was miserable as we exported $0.08 imported $2.96 so we were $2.98 in the red, we didn’t save any money that day.

In the last 36 days we have had 7 days where we have paid more than we have earned, every other day we have made money by saving around $3.50 per day on average.

A couple of days ago there was a notice in the newspaper, our electricity charges are going up 5.8% (I think that’s the actual figure) on January the first 2014!

Mick.

Well thank you optimark, that was a pretty good post.

We just got our first bill after installing solar.

In the past, we have had bills as high as about $700 for the quarter. This would have been mainly due to the cost of A/C.

However, our last bill was for a total of just $180.63. It would have been a fair bit higher, but we got back a total of $166.04 for the power generated, but what doesn't show in these figures is that all out hot water is now essentially free.

We have a timer on the system that will only allow the hot water to operate between the hours of ~9am to ~3pm. So far, we have not needed to switch on mains power to the hot water at all. As a consequence of this, I would estimate that our electricity bill has diminished by approx 2/3rds. This means that after just one quarter we are saving about $360 which means that it is about $1400 a year. So that would mean that the system would pay for itself after about 6 years and after that, it is all profit.

Actually, the way that they are starting to charge for electricity nowadys, that time period for ROI may decrease to about 4 or 4 1/2 years.

Whatever, I am really happy that we did make a decision to spend the money to future proof ourselves against rising prices.

Bob, we feel the same way about spending money now to future proof price increases.

As of today and with our best ever yet production of 32kW exact, we are now five months hooked up and in the system, our savings are $701.77.

Even allowing for January and February extremes and March humidity where we run air a bit, it would appear we will possibly save around $1,400 per annum at least, especially as there is a 5.8% increase in two days time.

We are conservatively estimating 7 years for ROI but it's possibly closer to 6 years, we'll see.

I was much taken with your HWS set-up, ours is gas and I thought we have oodles of gas in Australia, prices probably won't go through the roof. Well I backed the wrong horse there as gas prices are going to go up so much, they may even become a political issue.

Mick.

Hi Mick

My hot water used to be gas, but the cost of gas got so expensive that I cancelled it. I do, however, still use gas for cooking. But now, I only have one bottle of gas, not three.

Yeppers - the suns flipped upside down apparently.

Video: Sun has 'flipped upside down' as new magnetic cycle begins - Science - News - The Independent

Video: Sun has 'flipped upside down' as new magnetic cycle begins

All you blokes are gunna have to end for end the solar panels on your roof if you want to keep generating electrickery and not start suckin it back outta the grid!

Otherwise your positives gonna be getting negative rays and vice versa - which will suck power - not make it.!

Gotta do it every 11 years apparently.... every time the sun flips you'd think they would mount the darn things on a swivel base to make it easy for next time - wouldn't you. I think I'll offer that as an added extra maybe...swivel mounts for the panels - make it easy to do again in 11 years time.

It's taken me all day to do mine and the sun was a tad hot up there today so I did it at night time was best.

Since I launched "solar panel flippers" on line last week I haven't stopped - been flat out like a lizard drinking!

Keeps up like this I'll have to franchise it nationally.