Forums > General Discussion   Shooting the breeze...

Rooftop solar and battery back up

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Created by AUS1111 > 9 months ago, 18 Jul 2017
AUS1111
WA, 3621 posts
18 Jul 2017 10:13AM
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Does anyone know much about this? Obviously it is a great idea to generate electricity and store for future use, but what are the pros and cons?

Could you finance the initial outlay from the electricity savings over a period of time?

decrepit
WA, 12767 posts
18 Jul 2017 10:22AM
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I don't have any definite facts, so this is just a guess on my part.
I think it's cost effective in isolated areas where the cost of new poles and wire over a long distance is greater than the battery outlay. At the moment I don't think it quite makes it in suburban areas. In the future with electricity prices rising and battery prices falling it will probably get there.

Mark _australia
WA, 23452 posts
18 Jul 2017 5:11PM
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Not since the GovCo pushed it, then there was way more uptake than they expected so they reduced the amount for buyback. Mongrels.
However, in WA power is going up yet again so if battery life (as in how long they will live for not storage capacity) is good and also you are not working totally off how much you get for your input to the grid (like everyone did 10yrs ago) , then maybe.

Chris6791
WA, 3271 posts
18 Jul 2017 6:27PM
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I don't think the sums add up yet for solar/battery and totally going off-grid just yet. Though I'm happy for the rich greenies to keep spending money getting Tesla batteries installed, battery storage might only be the domain of those with a higher disposable income but the more they buy and install the more it will bring the price down to something viable for the average punter.

Crusoe
QLD, 1197 posts
18 Jul 2017 8:29PM
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Yeah batteries are about a 10 year payback for grid connected homes. But that's at todays electricity costs. So if you installed them now and electricity prices continue to go up then the payback time span will reduce. But battery costs may also come down.

You can get AC connected batteries, these have chargers and need inverters to deliver the stored energy back. And then there are the DC connected batteries that are connected between your Solar Panels and your existing inverter. They charge during the day and then continue to deliver DC to you inverter when the sun goes down. These are probably the best with regard to connecting to an existing, say 5kw domestic installation as their DC connection voltage is not that wide a range. Probably around the 500V mark. (Some of the bigger Solar Panel systems operate at around 800Vdc+). These DC connected batteries mean you can usually use all your existing gear without upgrading things like the inverter.

But a lot of these systems shut down if there is a power outage as the inverters need a grid connection. But there are systems (hybrids) out there (Like the SP Pro's - Selectronics) that have the ability to operate after losing a grid connection as they treat the grid as a way to charge the batteries and continue to run after Grid Failure till the batteries have reached a predetermined level. We have installed lights in peoples house to let them know they have lost grid power as the change over is seamless.

Just remember that batteries are not much chop for cooking a roast in the electric oven or the electric hot water system. There are some bloody good solar hot water systems out now. Plus you can get grid isolated solar setups for the pool pump. Some have special DC motors and some are able to use the existing pool pump with a special AC variable speed drive.

But everyone's situation is different, so if you really want to know what's right for you, then go down to the local solar installer and have a talk with them. Probably help if you find a business that has been around for a while and not offering a cheap prices because they are selling cheap equipment. Quality and service.

And for fu%k sake, don't believe the crap pricks like me may write on a forum.

You could just turn off one or two fridges. Reduce the number of TV's in the house to One, turn the lights off when leaving the room. What's that you say, you rather spend $10,000 dollars to fix the problems then changing your life style.

GPA
WA, 2528 posts
18 Jul 2017 10:24PM
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Spend a few hundred bucks and change all of your most used lights to LED...

Harrow
NSW, 4521 posts
19 Jul 2017 9:21AM
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Hold off a couple of years. Batteries are going to experience a price plunge just like solar cells have done over the last 3 to 5 years. It doesn't pay for itself yet.

kiteboy dave
QLD, 6525 posts
20 Jul 2017 7:59AM
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GPA said..
Spend a few hundred bucks and change all of your most used lights to LED...


I buy them 10 at a time from Hong Kong via eBay. About $2.80 for a 9W delivered.

Adriano
11206 posts
20 Jul 2017 7:10AM
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AUS1111 said..
Does anyone know much about this? Obviously it is a great idea to generate electricity and store for future use, but what are the pros and cons?

Could you finance the initial outlay from the electricity savings over a period of time?


The only con is upfront cost - for the time being.

Also depends on whether you're in the city or a rural area.

Also depends on whether you have the roof space to do it without making your house look like a shed.

In rural areas where the distance to grid connection is significant, solar is cheaper.

The best thing about grid connected solar/storage is that you are energy independent, offsetting filthy coal power and have a safeguard against blackouts.

Adriano
11206 posts
20 Jul 2017 7:17AM
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Harrow said..
Hold off a couple of years. Batteries are going to experience a price plunge just like solar cells have done over the last 3 to 5 years. It doesn't pay for itself yet.


To clarify. I would hold off on batteries for a few years if cost is a sensitive issue, but still install grid connected solar PV panels. Panels and inverters are cheap. For $5,000 you've got 3Kw - roughly. You can always add the batteries to a storage-ready system. When you add batteries you will probably also need to add another inverter/controller to monitor the whole house system and connection to grid.

Nathe
WA, 439 posts
20 Jul 2017 8:56AM
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$5000 will buy you a 5.5 kw system with German made panels and a fronius inverter. It's worth the investment if your staying in the house for awhile and also good to try and get our emissions down. I like the idea of not always paying big bucks to the power company

Mr Milk
NSW, 3115 posts
20 Jul 2017 12:44PM
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Think laterally. Use the surplus power to grow a bit of weed under LEDs.

FormulaNova
WA, 15084 posts
20 Jul 2017 12:21PM
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Adriano said..



The best thing about grid connected solar/storage is that you are energy independent, offsetting filthy coal power and have a safeguard against blackouts.


Unfortunately not. The inverters will shutdown when there is no grid, as a safety precaution.

If someone jury-rigs a way around this, then they potentially can create a life-threatening situation by livening up a dead section that someone may be working on under the assumption it is isolated.

On the other hand, if its isolated and not grid-tied, then it would be a safeguard. I don't know what the rules are around this though.

Adriano
11206 posts
20 Jul 2017 1:11PM
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FormulaNova said..Unfortunately not. The inverters will shutdown when there is no grid, as a safety precaution.

Adriano said..

The best thing about grid connected solar/storage is that you are energy independent, offsetting filthy coal power and have a safeguard against blackouts.

Unfortunately not. The inverters will shutdown when there is no grid, as a safety precaution.

If someone jury-rigs a way around this, then they potentially can create a life-threatening situation by livening up a dead section that someone may be working on under the assumption it is isolated.

On the other hand, if its isolated and not grid-tied, then it would be a safeguard. I don't know what the rules are around this though.

Sorry, but you don't know what you're talking about. You're wrong about hybrid systems shutting down during a blackout.

Just commissioned one system last month. Works fine. Grid connected hybrid. Has full blackout operation for up to 15kWh.

dreamliner
NSW, 110 posts
20 Jul 2017 6:30PM
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Been looking a bit more into this , as I don't require aircon , with my 5kw system already installed all I seem to really need is a small battery system to get me through the peak evenings where most of my usage and costs occurs.

Crusoe
QLD, 1197 posts
20 Jul 2017 7:56PM
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dreamliner said..
Been looking a bit more into this , as I don't require aircon , with my 5kw system already installed all I seem to really need is a small battery system to get me through the peak evenings where most of my usage and costs occurs.


Solarwatt - Have a read. It may be the best way to go.
https://www.batteriesandsolar.com.au/pages/solarwatt-battery-storage

Chris6791
WA, 3271 posts
20 Jul 2017 6:35PM
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Crusoe said..
Yeah batteries are about a 10 year payback for grid connected homes. But that's at todays electricity costs. So if you installed them now and electricity prices continue to go up then the payback time span will reduce. But battery costs may also come down.



The problem with this is that over here they have just jacked up power prices again but this time a big jump on the fixed daily supply charge. So with rebates for selling power pack to the grid close to nothing you still get a bigger bill. It would be almost impossible now to run a home solar system at a 'profit' whilst connected to the grid, even it you turned everything off and left the country for a whole bill cycle (which I've just done).

Adriano
11206 posts
21 Jul 2017 6:43AM
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Chris6791 said..


Crusoe said..
Yeah batteries are about a 10 year payback for grid connected homes. But that's at todays electricity costs. So if you installed them now and electricity prices continue to go up then the payback time span will reduce. But battery costs may also come down.



The problem with this is that over here they have just jacked up power prices again but this time a big jump on the fixed daily supply charge. So with rebates for selling power pack to the grid close to nothing you still get a bigger bill. It would be almost impossible now to run a home solar system at a 'profit' whilst connected to the grid, even it you turned everything off and left the country for a whole bill cycle (which I've just done).



Ahh to a point. They haven't jacked up connection charges that much. Depends on the design of your PV/storage system. If it's designed correctly you're making money, not paying.

If you have batteries, you're using very little or zero nett grid power. Modern hybrid systems are designed to drain batteries as low as possible at night to cycle the batteries and therefore you're using PV direct during daylight hours and batteries at night. Very little grid power is therefore required.

That's the beauty of hybrid. You're offsetting coal fired electricity production and paying no bills.

If prices go wild, keep adding panels/batteries or connect to a community micro grid and share storage.

Chris6791
WA, 3271 posts
21 Jul 2017 8:38PM
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I'm not sure how big the system is really matters in a residential setting, if you totally ignore the capital cost of a home system and it's well designed to catch as much sunlight over the entire day, and you have battery storage and don't draw a single unit of power from the grid- over here in WA you would still need to export 13 kWh per day at 7 cents a unit, every day to be cost neutral on each bill. Or you take the leap and go off-grid completely.

If you also want to cover the capital cover of panels and batteries by selling power back at 7 cents a unit you're dreaming, that would mean selling at least another 50-100 units a day. Unless you can generate power from moonlight and fairy sprinkles that's not achievable.

Three weeks ago they doubled the daily supply fee over here, it's a smart strategy and I'm surprised it took the state govt so long to have the balls to do it. A couple more big jumps in that fee will make Elon very happy.

Off-grid might be cost effective but how many people are going to be willing to totally disconnect from the grid? Plus I think sooner or later they tweak the legislation and the daily supply charge might be payable just to have the poles run past your house, whether you're connected or not. They already do it with the sewerage.

Adriano
11206 posts
22 Jul 2017 6:39AM
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Sounds like it's getting a bit dire over in WA. I don't know much about the grid pricing over there but in the east storage is becoming more attractive all the time - especially for new and rural housing.

I see community micro grids as being the future, with locally shared storage. That allows communities to get together and have the power lines removed entirely from the local area and give the power corporations the big middle finger. This is already happening especially in new 100% self sufficient developments.

Communities, not corporations are our future.

Adriano
11206 posts
24 Jul 2017 6:24AM
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AUS1111 said..
Does anyone know much about this? Obviously it is a great idea to generate electricity and store for future use, but what are the pros and cons?

Could you finance the initial outlay from the electricity savings over a period of time?


Just out of interest, what is the most expensive car in your garage and what's it's fuel consumption?

FormulaNova
WA, 15084 posts
24 Jul 2017 10:31AM
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Adriano said..

FormulaNova said..Unfortunately not. The inverters will shutdown when there is no grid, as a safety precaution.



Adriano said..


The best thing about grid connected solar/storage is that you are energy independent, offsetting filthy coal power and have a safeguard against blackouts.


Unfortunately not. The inverters will shutdown when there is no grid, as a safety precaution.

If someone jury-rigs a way around this, then they potentially can create a life-threatening situation by livening up a dead section that someone may be working on under the assumption it is isolated.

On the other hand, if its isolated and not grid-tied, then it would be a safeguard. I don't know what the rules are around this though.


Sorry, but you don't know what you're talking about. You're wrong about hybrid systems shutting down during a blackout.

Just commissioned one system last month. Works fine. Grid connected hybrid. Has full blackout operation for up to 15kWh.


Sure, I guess you COULD come back and add the word hybrid into the conversation.

Its like my steam locomotive that runs without coal. Did I mention that it has lithium ion batteries? Oh, you mean that changes the meaning of the statement? No kidding...

Gumble
NSW, 22 posts
25 Jul 2017 6:25PM
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Just stumbled on the conversation. Currently looking to build on rural block with 11kv lines out front. Then have a 300m run to house. Current quotes to the house around 45k.
Was looking to have solar panels from start so their cost is neutral.
Are we at the stage with batteries that we could possibly invest that 45k into storage (batteries) stay off the grid and be viable ?
Cheers
Matt

SandS
VIC, 5904 posts
25 Jul 2017 6:55PM
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Gumble said..
Just stumbled on the conversation. Currently looking to build on rural block with 11kv lines out front. Then have a 300m run to house. Current quotes to the house around 45k.
Was looking to have solar panels from start so their cost is neutral.
Are we at the stage with batteries that we could possibly invest that 45k into storage (batteries) stay off the grid and be viable ?
Cheers
Matt


45k for a 300 mtr trench and cable sounds excessive , what is the ground like solid rock ? ..... get a price from someone who wants to do the job with out ripping you off

Gumble
NSW, 22 posts
25 Jul 2017 7:18PM
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No . Ground etc is all good. Have to install pole mounted transformer across rd.
Will run mains conduit etc myself.
Its the tranny and mains the main cost . Was hoping to get off the grid to beat the rising costs and bs charges .
Cheers

Mr Milk
NSW, 3115 posts
25 Jul 2017 8:03PM
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I would guess that batteries for a day or 2 worth of power would be much cheaper, but you would have to have a generator back up for the odd wet week in winter when your solar can't recharge the batteries

jn1
SA, 2636 posts
25 Jul 2017 8:23PM
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Crusoe said..
You can get AC connected batteries, these have chargers and need inverters to deliver the stored energy back. And then there are the DC connected batteries that are connected between your Solar Panels and your existing inverter.

Hi Crusoe, could you explain what an AC connected battery is ?. What is the difference between an AC and DC connected batteries ?

I move into my new house on Friday, and with the energy hikes in SA, I've taking a keen interest in this topic.

Chris6791: I agree with you about government tweaking laws to charge people for supply availability. They don't ever play fair



Chris6791
WA, 3271 posts
25 Jul 2017 10:49PM
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Gumble said..
Just stumbled on the conversation. Currently looking to build on rural block with 11kv lines out front. Then have a 300m run to house. Current quotes to the house around 45k.
Was looking to have solar panels from start so their cost is neutral.
Are we at the stage with batteries that we could possibly invest that 45k into storage (batteries) stay off the grid and be viable ?
Cheers
Matt


Sounds cheap. It cost me $28k to move a power pole 2.2 metres.

Adriano
11206 posts
26 Jul 2017 5:39AM
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FormulaNova said..

Adriano said..


FormulaNova said..Unfortunately not. The inverters will shutdown when there is no grid, as a safety precaution.





Adriano said..



The best thing about grid connected solar/storage is that you are energy independent, offsetting filthy coal power and have a safeguard against blackouts.



Unfortunately not. The inverters will shutdown when there is no grid, as a safety precaution.

If someone jury-rigs a way around this, then they potentially can create a life-threatening situation by livening up a dead section that someone may be working on under the assumption it is isolated.

On the other hand, if its isolated and not grid-tied, then it would be a safeguard. I don't know what the rules are around this though.



Sorry, but you don't know what you're talking about. You're wrong about hybrid systems shutting down during a blackout.

Just commissioned one system last month. Works fine. Grid connected hybrid. Has full blackout operation for up to 15kWh.



Sure, I guess you COULD come back and add the word hybrid into the conversation.

Its like my steam locomotive that runs without coal. Did I mention that it has lithium ion batteries? Oh, you mean that changes the meaning of the statement? No kidding...


You'd be pretty dumb not to fit hybrid inverters to a grid connected solar PV storage system. I didn't add, you've just discovered the best practice, logical installation is hybrid. Not going hybrid is so 1999.

Adriano
11206 posts
26 Jul 2017 5:43AM
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Gumble said..
Just stumbled on the conversation. Currently looking to build on rural block with 11kv lines out front. Then have a 300m run to house. Current quotes to the house around 45k.
Was looking to have solar panels from start so their cost is neutral.
Are we at the stage with batteries that we could possibly invest that 45k into storage (batteries) stay off the grid and be viable ?
Cheers
Matt


Wow that's a nasty quote. Shop around mate. Should be about 1/3 that amount. I just finished a hybrid job with 100m of underground grid and it was $3500.

$45K just about gets you off grid with diesel gennie backup, but it depends on your house design. If it's a well designed house with small footprint and low energy consumption $45K could work. If it's a McMansion, forget it. You're going to have to outlay double that.

Who gave you the quote? The utility company? If so, you can arrange to sub-contract the trenching yourself. Trenching is where the money is made, not the wires. Wires are cheap. Downtime is small.

Also, is the 300m on or off property?

Chris6791
WA, 3271 posts
26 Jul 2017 4:45PM
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^^^ the big cost is probably providing a transformer to step down from 11kv and get it onto the property.



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Forums > General Discussion   Shooting the breeze...


"Rooftop solar and battery back up" started by AUS1111