Pink batts revisited

14 Responses to Pink batts revisited

1. Roger

   #2889312, posted on December 20, 2018 at 11:24 am

   In Australian politics these days they call this “moving forward on climate change”.
2. John Constantine

   #2889332, posted on December 20, 2018 at 12:01 pm

   If we burn down a quarter of the houses with peoples liberation army slave labour solar panels on them, this will boost our gross domestic product and allow us to mass import visa voters to assemble dogbox apartments to replace them.

   Burning up our deplorable housing stock Is Our Strength.
3. duncanm

   #2889355, posted on December 20, 2018 at 12:31 pm

   how does one get shocked with the sub-20V wiring on the roof?

   Don’t they install the inverters down near the 240V mains box ?
4. RobK

   #2889389, posted on December 20, 2018 at 1:04 pm

   Duncanm,
   Domestic solar is limited to 300v dc, commercial PV can runout to 900v dc (for 3 phase inverters). Some PV panels have a little inverter at each panel, but most systems on domestic installations are 300v dc to the inverter, generally mounted near ground level. The higher voltage reduces losses and allows for lighter cabling.
5. Brian

   #2889392, posted on December 20, 2018 at 1:06 pm

   One source suggests that solar panels can generate up to 600V DC and they can source a lot of current. To get this voltage the panels are wired in series so each step of “12V” adds to the next for total voltage.
   Solar Panels have no “off” switch – so they generate electricity whenever the sun is shining on them.
   And this is the great danger – as long as they are in sunshine they are lethal.
   Incidents noted on Whirlpool include the measurement of 100V between the array and the roof.
6. RobK

   #2889393, posted on December 20, 2018 at 1:07 pm

   Duncanm,
   Larger panels are around 40v each and connected in series to make a string to output 300v, or so, for domestic.
7. yackman

   #2889433, posted on December 20, 2018 at 2:06 pm

   We live in a rural area and all roof surfaces are Colorbond. Risk is part of the reason we have never installed Solar PV. the difficulty of maintenance was another
8. duncanm

   #2889529, posted on December 20, 2018 at 4:14 pm

   RobK – I suspected that might be the case. Makes sense.

   Ouch – and yackman , a tin roof is double ouch. Nothing like getting zapped cleaning the gutters, or watching your roof and downpipes rot away due to DC leakage.
9. The BigBlueCat

   #2889617, posted on December 20, 2018 at 5:35 pm

   I’ve mentioned before in a previous post regarding how shoddy even certified PV installers have been for us at (the previous) Chez BigBlueCat … the qualified sparkie failed to secure an electrical cable behind the switchboard, causing an intermittent short. They even had a second sparkie inspect the work for safety certification purposes, but failed to spot the problem.

   We only found out because the safety switch kept tripping. The sparkie that repaired it said our house could have burnt down.

   I’m not saying all installers are like this, but even if 0.1% are duds, that still means a lot of potential disasters out there, all relating to PV installations. And the government wants to increase that???
10. Squirrel

    #2889634, posted on December 20, 2018 at 6:00 pm

    A further risk with the rooftop panels is the accumulation of leaves and other debris in areas under threat from bushfires.

    As to the economics of this mad fad, three years back, the Grattan Institute (not known as a nest of coal-fancying, climate change denialists) pointed out the costs of government subsidies –

    https://grattan.edu.au/report/sundown-sunrise-how-australia-can-finally-get-solar-power-right/
11. Bruce

    #2889723, posted on December 20, 2018 at 7:58 pm

    Maintenance and cleaning are two reasons NOT to put these things on a roof. Doing a “Molly Meldrum” is not a good look.

    If you have the yard space, panels should be arranged in arrays on top of sturdy steel poles. This allows for optimum alignment with the big thermo-nuclear device in the sky AND simplifies inspection and maintenance.

    There is no point in anything under 20 Kilowatts off the array as well. The battery banks should be able to instantaneously able to take up the slack as load on the inverter increases at peak times.

    If your inverter does not produce a pure 50Hz sine-wave at a steady 230V, UNDER LOAD, you will start losing appliances, especially those with motors, like fridges and freezers; not much fun when several Kilos of seafood goes off over a weekend away because the compressor motor has been fried by dodgy electricity..
12. yackman

    #2889766, posted on December 20, 2018 at 9:22 pm

    Further to the comments re cleaning; I have speculated on the losses that would occur in high particulate areas such as cities as panels become occluded . Some installations in Melbourne are on very steep roofs and inaccessible to most people. As I am in my later years I rarely go on my roof which is not steep. Perhaps to put in the gutter blocks during a fire.
13. yackman

    #2889893, posted on December 21, 2018 at 7:48 am

    re Bruce at 7.58; I looked at ground based array installation and found that the additional costs would be rather too much to justify the investment. Ideally an FTSR (Follow the Sun Rack) would be best but expensive. 20 kWh of battery would also be very expensive.
    Your comment about stable voltage and profile is interesting as quite often our grid input hits 250 V so 230 v would not be exportable?
    There are plenty of installations around our area which does have fires and the cleanout from the gutters this year( done by the son-in-law) yielded two full buckets of waste so plenty to accumulate under arrays.
14. Mark A

    #2889894, posted on December 21, 2018 at 8:06 am

    yackman
    #2889893, posted on December 21, 2018 at 7:48 am

    yackman, a good inverter will work well within the input voltage range and give you a steady output as long as it’s working.
    Much better regulation than the main line actually.
    (in fact some sensitive equipment is run on inverters from the mains)

    250V is OK, every appliance can handle that, on the other hand much lower than 230V and your problem starts with induction motors starting up. once they are running they will keep running, but fridges and others will turn off occasionally and restarting will be a problem.

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