Solar... who's clued in?

stirk

Burner
Quick question around this.

I am well into a reno & have just confirmed the solar installer. The architect has just come back to me saying the roof will need to be reinforced to support the additional load of the panels, with an additional cost of course.

Several friends & family have gone down this road recently & I have never of heard anything like this, anyone else?

I'm calling BS
Here's your problem..
 

Attachments

sane

Likes Bikes and Dirt
Yes, it was in the original scope, so the roof is not fit for purpose as I see it
Yes, I have asked the installer, who said it's bollocks, but I can always install after completion

Still too angry to respond to the email.

ffs
 

Skydome

What's invisible and smells like hay?
I've never heard of those solar panel brands.

On my house I am using REC Twin peak 2 panels and they have been doing great, I have a 5.2Kw system and the day before it produced 42kw of energy for the day and it averages around the 25-39kw mark depending on cloud, obviously it drops a lot with the rains.

Other panel brands to look at are of course LG but also Sunpower as well as REC as for your inverter, fronious (SP) get reviewed well but so too does Solaredge, i'd stick with fronious and don't budge if someone offers something else you haven't heard of.
 

99_FGT

Likes Bikes and Dirt
I've never heard of those solar panel brands.

On my house I am using REC Twin peak 2 panels and they have been doing great, I have a 5.2Kw system and the day before it produced 42kw of energy for the day and it averages around the 25-39kw mark depending on cloud, obviously it drops a lot with the rains.

Other panel brands to look at are of course LG but also Sunpower as well as REC as for your inverter, fronious (SP) get reviewed well but so too does Solaredge, i'd stick with fronious and don't budge if someone offers something else you haven't heard of.
Where the f ck are you to be getting more than 8kwh/kw?
I can point you to any number of guys who would love to know how you can do that, even single axis tracking doesn't get there.
 

rowdyflat

chez le médecin
Architect is responsible =def not fit for purpose. . prolly the arse covering just backfired.
But as you said if the installer can jump all over the roof surely the static weight of a few panels wont hurt.
I have only heard this is an issue on huge spans w no intermediate supports.
Our local hall is a bit like that, just wide truss spans.
 

Flow-Rider

Wheel size expert
Architect is responsible =def not fit for purpose. . prolly the arse covering just backfired.
But as you said if the installer can jump all over the roof surely the static weight of a few panels wont hurt.
I have only heard this is an issue on huge spans w no intermediate supports.
Our local hall is a bit like that, just wide truss spans.
Depending on where and how the house is being built or how exposed to high winds winds, it might have something to do with the wind pushing on the panels if they're not installed flush with the roof. Houses are built as cheap as possible these days, the house I'm living in is a double brick cavity home from the 70's with hardwood roof trusses as opposed to single brick with plaster board walls and pine roof trusses.
 

Skydome

What's invisible and smells like hay?
Where the f ck are you to be getting more than 8kwh/kw?
I can point you to any number of guys who would love to know how you can do that, even single axis tracking doesn't get there.
Tassie :p

I have a 5.2 system but the day it produced 42kwh for the day it was going bonkers and was consistently doing around 5Kw/h.

Obviously the system struggles on darker days but once the sun kicks in the system tends to go a bit nuts, right now as I type this the panels are pulling in 4.9kw
 

99_FGT

Likes Bikes and Dirt
Tassie

I have a 5.2 system but the day it produced 42kwh for the day it was going bonkers and was consistently doing around 5Kw/h.

Obviously the system struggles on darker days but once the sun kicks in the system tends to go a bit nuts, right now as I type this the panels are pulling in 4.9kw
Ahh, makes sense.
The back of my neck agrees with the solar intensity, and the kids are reminding me how long the days are. In summer.
 

Nambra

Postmeridian
So I'm getting close to pulling the trigger on a solar PV system at home. Have spent the past few weeks reading, e mailing and talking to so many sources my head is spinning. It's a really strange industry, seemingly flooded with cheap and nasty companies just trying to undercut each other in order to sell as many units as possible before closing up and running for the hills. Amongst these are the reputable, genuine companies who actually know more than can be read on their web page and actually care about giving you the right advice and product. It's a slippery course to navigate but I'm slowly whittling away the cheapos and rip offs and am settling on a particular configuration of 5.4kw system with Fronius single phase inverter and panels either by Jinko or et solar.
Quotes for identical systems in terms of these components vary from $5300 to $7700, which is huge in terms of percentage. They all spruik certified electricians, installers, system engineers, cec accredited independent inspections same warranties on products and workmanship, so the hard part is believing they'll still exist long enough to honour a 25 or even 10 year warranty..
So where is the rest of the value? One company offers lifetime system analysis so as to be able to inform us on more beneficial energy usage patterns, or issues with power generation etc, so that could be handy but not essential.
Who around Melbourne or within Victoria has had a system installed, and what would you recommend to help sift through the shit and not get ripped off but at the same time not just assume more expensive is better? I'm leaning toward a company that's about middle ground price wise, seem pretty honest, get decent independent industry reviews and are local and been in business for years. But any advice or experiences would be great to hear before I throw down 6-7k.
I installed a 6.4kW system on my house in QLD about 8 months ago, and whilst it is not Melbourne, I too anguished over all the literature, hype and bullshit during the selection process. I'm also an electrical engineer so have a pretty good understanding of what is truth and what is horseshit coming from the salespeople I dealt with from the prospective vendors.

To address some of your comments and some things in general:
1) I'm fairly certain that ALL installers need to be CEC accredited these days - the industry has cleaned up it's act after a lot of dodgy installers put systems in and people's houses burnt down.

2) Premium panels usually have a much better performance guarantee eg. guaranteed electrical output after 25 years - this is what you should be looking at in terms of degraded performance over time. You can calculate this out as an actual cost (ie. better output for longer saves you money) and determine if a more expensive system with better panels will cost you less in the long run. I went with LG Neon 2 panels (19.2% efficiency, and a 25 year output guarantee of around 83% which is very good) - they are also 320W panels, so it maximises output per square metre of roof space if you have limited roof area.

3) These 'lifetime system analysis' offers are crap IMHO. All they do is set up the inverter to connect to your home WiFi and send data back to a centralised database that they can pull data out of and send you fancy looking reports. If you keep an eye on some basic things yourself, it's easy to tell if the system is healthy and working as intended. If, however, you're a set and forget sort of person, paying a premium for a monitoring service will mean you will be alerted quickly to any system faults that result in no power output (rather than discover it yourself when you get your next power bill). If you have a new 'smart' energy meter, you can generally get access to your metering data from your retailer, and get an hour-by-hour view of you home energy usage, including solar output. That's a free service from your retailer (well it is with AGL).

4) Your roof area, pitch, shading and which direction it's facing will be important factors to consider. A ~25 degree pitch north facing roof with no shading is ideal, and will also mean a much simpler and cheaper install. Why? Because you'll only need one 'string' of PV panels and central inverter. Where your roof area faces several directions and when there is partial shading needs some more thought to maximise the efficiency of the system. My roof for example had NE and NW facing roof areas, but very little shade on each. I went with a Fronius inverter that supported 2 PV array strings (two independent arrays of panels back to the one inverter). It allows the inverter to maximise the output of each roof face independently of the other - the NE facing roof cranks out more in the morning, whilst the NW roof performs better in the afternoon.

5) The problem with series connected PV panels is that the whole 'string' only performs as well as the poorest performing panel in the string. If one panel is faulty, the whole string goes down. If a couple of panels are partly shaded during the day, the whole string output reduces accordingly. Part shading of roof area makes a good case for micro-inverters - each panel essentially has it's own inverter and the maximum possible output from each panel is ensured all the time, regardless of shading on other panels. Plus they are generally smart devices and you get masses of wonderful marketing data from them like how each panel is performing compared to the others. Micro-inverter systems are also more expensive, and only give you marginal performance gains over central inverter systems when you have no shading issues. I considered it when looking at my system, but the economics didn't stack up because of my roof configuration. I also don't like the idea of having sensitive electronic equipment sitting up on the roof in the baking heat year in year out, getting shat on from the heavens all the time. A cheaper alternative to micro-inverters for partial shading is a chainsaw...

6) There are some physical limitations when connecting a solar system to your house (bit of simplified electrical theory here). For an inverter to send excess power back to the grid, it has to increase it's output voltage so that it's higher than the grid voltage. If this voltage is too high, it will start messing up things in your house. Most electronics can tolerate over-voltage for short periods, but it will reduce operating life over time. Think electronics primarily, and fridges. Modern inverters will generally have a maximum output voltage to help protect your household goods, but this limit may also prevent the inverter from sending all available solar energy to the grid, reducing your feed-in kWh (not that you get much $ for them these days, but it still adds up over time). If you have a house with 3-phase power, then you can largely avoid this problem with larger Solar PV systems (>=5kW or so). The other limitation we have in QLD (other states may be similar) is that above 5kW, the inverter needs to deliver power to the grid with a power factor of 0.9 - it's an AC electricity concept (phase relationship between voltage and current), but in net terms it means you only get 90% of the output from your inverter. This is done to help reduce over-voltage action on the local electricity grid. So my 6.4kW PV array is connected to a 6kW inverter, but is limited to 5.4kW of actual electrical output. The large 6.4kW array is still beneficial in that I get 5.4kW of available power for longer during the day (kicks in earlier and cuts out later). Because my 6.4kW array is split across two different facing roof areas, it doesn't usually peak more than about 6-6.1kW on any given day, so I'm not losing much by only having a 6kW inverter (instead of one sized for the maximum PV array kW).

All of the above should be part of any well-considered offer you might receive from a solar company. Bear in mind though, that they can't afford to do the 'detailed design' up front for each customer to ensure the best system for the application - they couldn't compete. So they dazzle you with marketing spin on the basis that you're an uneducated buyer and will trust their 'professional' recommendations.

Hope this provides some background to inform your own decision making. You mileage will obviously vary, so do your own homework and don't rely solely on the above.
 

PINT of Stella. mate!

One Scotch & Joke
Quick question for any of you out there with Solar. Due to the storms last night, the power's been out in my 'hood all morning. No problem, I thought. I've got Solar. That'll kick in and I'll at least be able to check in with the security cameras at the house.

No luck. No power. My mates' houses are the same in spite of us all having Solar installed. Does anyone know if this is just a case of weak-arse solar generation on an overcast day, or is there a safety feature that cuts off your solar input in the event of power cuts to stop any excess power getting back onto the grid?
 

DMan

alid sinistra oliva
Quick question for any of you out there with Solar. Due to the storms last night, the power's been out in my 'hood all morning. No problem, I thought. I've got Solar. That'll kick in and I'll at least be able to check in with the security cameras at the house.

No luck. No power. My mates' houses are the same in spite of us all having Solar installed. Does anyone know if this is just a case of weak-arse solar generation on an overcast day, or is there a safety feature that cuts off your solar input in the event of power cuts to stop any excess power getting back onto the grid?
I'm not sure (because the power would fluctuate and damage appliances??) why but it sucks eh. They don't work without "power" supplementation. I hoped for the same thing when I got solar. So when there is a power cut you aren't any better off than the rest.
 

Tubbsy

will do custom titles for cash
Staff member
Even with a battery I don't think the grid permit you to do this, can't remember the reason - @Haakon?
 

Tubbsy

will do custom titles for cash
Staff member
No idea, im not a sparky. will depend how the meter is set up i assume...
Ok I just hambo'd and this is the reason:

Your grid-connected solar power systems must by law shut down if the grid loses power. The reason is that linesmen repairing faulty electricity wires must be able to do so safely, without any solar power travelling back into the grid during maintenance and repair. Your electricity if fed back into the line could create a danger to the service personnel. Therefore when there is a black out you will also be without power. Your solar power system will automatically turn on during daylight hours when the power comes back to the grid.
 

boyracer

Likes Dirt
My 3 Kw system is now so old now i can't remember the specs...12 years on the roof so far. I reno'd the house with ducted evap/ LED's all round and gas HWS/ heating.
Bills slowly creeping up to ~100 a quarter for family of 5. Mostly the bloody service fees. Mum has been largely work from home for a while now which has added $$ too. System has paid for itself twice over by my estimation, not including Govt $$.
0.52 c input here helps too.
We're getting a lot of letterbox/ inbox clutter at the moment about adding batteries but can't see the payback potential being proportional to actually 'making' the free electrons. Obviously dependant on your energy auditing but apart from the blackout protection not a huge consideration.
 

PINT of Stella. mate!

One Scotch & Joke
Ok I just hambo'd and this is the reason:

Your grid-connected solar power systems must by law shut down if the grid loses power. The reason is that linesmen repairing faulty electricity wires must be able to do so safely, without any solar power travelling back into the grid during maintenance and repair. Your electricity if fed back into the line could create a danger to the service personnel. Therefore when there is a black out you will also be without power. Your solar power system will automatically turn on during daylight hours when the power comes back to the grid.
That's what I thought. It's a shame you can't isolate your house from the grid in instances like this.
 

Dales Cannon

Deleted Banned Moderatuuur
Staff member
That's what I thought. It's a shame you can't isolate your house from the grid in instances like this.
You can...

You need to have a 3 way switch installed to isolate mains infeed. I do it with my generator. The generator is isolated unless the switch is flipped then only the house (two circuits as it is wired 3ph) are energised, fridge, freezer, water pump, hot water trigger, biocycle, TV, stereo etc. No back emf into the grid but set up has to be inspected and approved, here anyway. I don't wake up the solar though, the demand can't handle the supply and one or other sources could release the magic smoke. Maybe. Not worth the risk. Potentially hard on consumers in the house if solar is up and down with cloud cover. I am assuming the solar inverter can just ramp down to meet demand, not sure what happens when demand > than supply... my house generator is 3.5kVA and solar is 3.5kW.

Biggest issue is knowing when power is back as neighbours are not close.
 

boyracer

Likes Dirt
You can...

You need to have a 3 way switch installed to isolate mains infeed. I do it with my generator. The generator is isolated unless the switch is flipped then only the house (two circuits as it is wired 3ph) are energised, fridge, freezer, water pump, hot water trigger, biocycle, TV, stereo etc. No back emf into the grid but set up has to be inspected and approved, here anyway. I don't wake up the solar though, the demand can't handle the supply and one or other sources could release the magic smoke. Maybe. Not worth the risk. Potentially hard on consumers in the house if solar is up and down with cloud cover. I am assuming the solar inverter can just ramp down to meet demand, not sure what happens when demand > than supply... my house generator is 3.5kVA and solar is 3.5kW.

Biggest issue is knowing when power is back as neighbours are not close.
Was just about to add this. Dad's still a licenced sparky so was factoring this in to battery install equation. Legal in SA
 
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