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goughy

Solar power, cost, installation etc etc

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Have been doing the due diligence on solar for my new place in Broulee. Originally going with battery ( that would give power during a blackout ), but the initial capital expenditure, was just not worth it with battery costs at the moment. ( $25,000 all up )

Going with 5.2kW system, 3 phase ( but with conduit for battery install down the track.) Ends up being around $8,000 installed and commissioned, grid connect. Metering is now done by the local power provider in our Shire, not sure about other places.

Our aim is to be able to produce our own power and if we can sell back to the grid, we will. It's not about making any money. On the new build, we have no pool and only A.C units and a mega roller door ( 7.2m wide ) that require the 3 phase. 

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16 hours ago, roxii said:

Only that generally for business batteries make less sense, as most business takes place during business (aka daylight) hours. 

My wife is thinking of getting solar panels on the roof of the pre-school she runs. 99.99% of their power usage is during daylight hours, and when they are vacant during 12 weeks of the year any feed in tarriff will be a bonus. 

 

I may have posted this before somewhere but I've done a bit of experimenting with traditional lead acid batteries and, according to me at least, this is the deal:

let's say you want to push 1 kWatt (1000 Watts) for an hour, ie 1 kWh.  Let's use the industry standard 12 Volt 100 AH sealed lead acid SLA) batteries 

You start with dividing the power by the volts (nominally 12) to get the current, which when you add 10% for losses gives around 1 battery, ie around 100 amps. So does this mean I it is 100 amps for an hour, therefore I only  need 1 battery?!

No. A battery's rating is done over a longer period of time (usually 20 hours) so if you want to suck it all out in 1 hour you have to de-rate it, a lot. Say 40%,  So, now you actually need 2 and a half batteries. So I can get by with 3 batteries?

No.  The deeper the discharge cycle the shorter the battery life.  A 100% discharge will kill it pretty quickly.  Best to be only 40% or less, so now we de-rate the batteries by another 2.5. So now you need 6 batteries for your humble 1 kw hour. 

Cost is around $200 per battery if you shop around so looking at $1,200 for batteries. You will also need some pretty heavy duty cabling (not cheap) and a good solar controller/ charger preferable the more efficient *MPPT type.

The good news is the Lithium batteries do not de-rate nearly as much as SLAs so you will need a lot less for a given output but they are more expensive and have their own quirks.

*How you wire up your batteries (ie all parallel for 12 volt or series parallel for 24 volt) has a big affect on what charger panel voltage and/or inverter you need.  If you have a 12 Volt system and 30 volt panels you must go MPPT.  If 24 volt system and 30 volt panels you can probably get away with PWM without too much loss of efficiency.  Series connection of batteries can be prone to balance issues that will reduce the overall capacity and may prematurely shorten the batteries' lifespan. 12 volt systems require twice the current so bigger cables, bigger fuses, bigger everything needed.

 The short answer is don't do it and wait until lithium batteries get cheaper! :) 

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You lost me at "I may have posted"..........

But I understood your short answer :)

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13 hours ago, Alex Simmons said:

My understanding is that not even a battery system will keep you immune from blackouts. The system shuts down along with the blackout. But I could be wrong, I'll defer to experts but that is how I understand it.

A UPS & a back up generator is the best way to ensure you never have a black out.  

In SA we had a major power failure about 12months ago.  Living next door to bikies had it's advantages on that day. They quickly got a generator set up & running. They chucked an extension lead over the fence for us so we were able to watch tv & cook dinner.  I guess they needed to keep the drug lab ticking along. 

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33 minutes ago, Bored@work said:

A UPS & a back up generator is the best way to ensure you never have a black out.  

In SA we had a major power failure about 12months ago.  Living next door to bikies had it's advantages on that day. They quickly got a generator set up & running. They chucked an extension lead over the fence for us so we were able to watch tv & cook dinner.  I guess they needed to keep the drug lab ticking along. 

I can imagine those words and a picture on the www.realestate.com.au ad for your house...

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45 minutes ago, pieman said:

I can imagine those words and a picture on the www.realestate.com.au ad for your house...

They moved out about 8months ago.  The funny thing was coming home after a ride in full Lycra with 15 guys sitting on Harleys out the front. Rode past them, quick nod of the head & continued on.

TBH we didn't have any problems with them. We spoke briefly & kept to ourselves. I don't think they want the attention around their house.

Worst thing is SA is such a small place. I was out at a work lunch with the senior management team & some of the big players from the USA. When the bikies walked past & of course they went "morning Dave"........  Try explaining that one.

 

 

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4 hours ago, Bored@work said:

Worst thing is SA is such a small place. I was out at a work lunch with the senior management team & some of the big players from the USA. When the bikies walked past & of course they went "morning Dave"........  Try explaining that one.

No worse than being freshly engaged, and taking my future wife into a country pub where I'd been working for the past few months. She was passing through to pick me up to go to a race. As we walked in, the drop dead gorgeous young barmaid call's out "Hi Tony", and has a beer on the bar for me before I'm 3 steps into the place.

You could have started a bush-fire with the glare I got from my fiance. :shy:

Edited by Ex-Hasbeen
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6 hours ago, Bored@work said:

A UPS & a back up generator is the best way to ensure you never have a black out.  

In SA we had a major power failure about 12months ago.  Living next door to bikies had it's advantages on that day. They quickly got a generator set up & running. They chucked an extension lead over the fence for us so we were able to watch tv & cook dinner.  I guess they needed to keep the drug lab ticking along. 

Yeah, good for basics but not much fun when the AC goes down on a hot day/night.

This is what they say on the Tesla site:

Quote

How does Powerwall work during an outage?

Powerwall can detect an outage, disconnect from the grid, and automatically restore power to your home in a fraction of a second. You will not even notice that the power went out. Your lights and appliances will continue to run without interruption.

If you have solar and Powerwall, then solar energy will continue to power your home and recharge Powerwall. Without Powerwall, solar will shut down during an outage.

We estimate how long your home will stay powered during an outage based on your indicated home size and the appliances you elect to back up, derived from national data. With solar, your Powerwall charge will deplete only when your home energy usage exceeds your solar power production. We cap our estimate at 7 days to account for the occasional cloudy day that may impact solar production.

So if that's true, it may actually provide a decent solution for areas prone to regular grid outages. I still expect it to be an expensive solution though.

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On 1/24/2018 at 3:12 PM, Cottoneyes said:

Solar panels feed into the network first and then back to your house / business - unless you have a battery.   So in a blackout the panels don't keep your lights on by themselves

That was the way systems were once wired when large FIT's were payed by the state governments. Called Gross metering

This was because you would sell everything generated for 60c/kwh and buy it back for less than 20c/kwh

Systems are now set up to "net metering" so that power is consumed onsite first, anything surplus to needs is then exported.

The reason solar systems are required to automatically switch off in a blackout is prevent them feeding power into the grid than may be under repair and so put workers lives at risk. Its a safety measure.

Some battery systems will still not prevent this (i.e. they will still showdown and you still are left in the dark) unless the system is set up for "islanding". When the grid goes down you are set up like an "island" so that you can continue to use your batteries, but all exports are restricted (again, to protect others)

 

 

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Luckily for me I live 10min from work. Work has a massive UPS with two CAT Generators.

 

Any black out & I pack up & drive to work. Coffee machine, big screen TV, comfy couch & aircond.

 

 

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Had a drive around southern tablelands today. Loved seeing a 51 turbine wind farm at Taralga and a 73 turbine wind and 42,000 panel facility at Crookwell. They can supply 45,000 and 70,000 houses with power. Since seeing a wind farm up close while cycling in Germany and Holland I am astounded with the opposition to them. 

Reading about these 2 facilities within a few hours of Sydney, I was disappointedly to read that one is owned by the Chinese government and the other by a Chinese publicly listed company

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We got our first electricity bill for the new house  with a 3kw system & 55c feedings tariff. Average cost per day $2.10

Our old place with no solar panels and running a pool pump and filter $16.50 a day. 

The old place didn't have gas and the new one does so we are expecting the delta to reduce. 

We are really happy not to be paying $1500 power bills anymore. The extra coin will got towards the added mortgage. 

 

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On 1/25/2018 at 3:33 PM, Alex Simmons said:

Yeah, good for basics but not much fun when the AC goes down on a hot day/night.

This is what they say on the Tesla site:

So if that's true, it may actually provide a decent solution for areas prone to regular grid outages. I still expect it to be an expensive solution though.

I am not completely up on that but I was under the impression that you cannot use your inverter to power during a blackout.  Grid tie inverters synch to the mains and are designed to switch off in the event of a power failure. 2 reasons for this - if an electrician disconnects the mains power he needs to know that there is not a 240 volt source still there waiting to kill him and secondly, if the inverter is still on when the mains is back on it may have lost synch, in which case it could be completely out phase when the mains comes back and lots of smoke and crackling noises could result.

*edit - I also think that grid tie inverters aren't built to cover the kinds of surge current that would be experienced in a back-up power situation, eg motors turning on, where currents 2 or even 3 times need to be catered for.

 

Could be wrong, but if it is done interesting to hear how it is done.  I have an off grid inverter which for all intents and purposes is like a back up generator but I have to make my own "extension cable network" to run power to the items that need it and NOT use the house wiring.

Edited by Pete

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Currently in the process of getting quotes from 3 recommended suppliers. I did up a reasonably decent briefing, provided quarterly consumption data for last 9 quarters, broke out the off-peak hot water usage (since that's at ~11-12 cents/kWh so no point putting that on solar) and have had all 3 visit to inspect the place and discuss options.

My expectations before starting is that the 3 quotes will be not directly comparable, it'll be apples with oranges.

So far that's looking like the case based on our meetings. I'm OK with that because it's not the price that will be my primary deciding factor (provided it's not ridiculously different). What I'm looking for are the other factors, suitability of the proposed solution, quality and durability of the technology, how the process is managed end to end, ability to add tech later without pain and the financial projections. Then there is the after sales service and longevity of the business.

One quote has arrived, two others due soon.

It's interesting to get a sense of who knows their stuff, can properly address the specific situation we have and not hand wave away certain issues.

In particular is the fact we have 3-phase power and that presents some challenges when it comes to potential for battery storage and uninterrupted power supply. I've been reading up on all the various configurations in this article:

https://www.solarquotes.com.au/blog/home-batteries-3-phase/

Boy, this is one thing I'll need to get right so I don't get hammered later if we decide to retrofit battery storage later. Already I can see on the one quote we have that the solution is somewhat technically limited and the financial projections don't account for the limitations of the proposed solution (not to mention the unduly optimistic and pessimistic assumptions designed to make the financial return look a lot better than it really will be).

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