Nick Rosen | |
Solar roof - but no power

With Queensland’s capital Brisbane devastated in the Australian floods, householders are learning the disadvantages of grid tied solar.

Because of the way Utility companies in Australia and the world over, insist on gaming the system, grid-tied solar panels only produce power when the grid is running. So they fail to fulfil the main purpose that many people buy  them for – to give safety and independence from the collapsing energy and financial system.
However, there are ways to convert a grid-tie system to work off-grid in emergencies – just a shame that the Utility companies do not provide a simple trip switch to allow homeowners  to operate the panels off-grid when needed.
Here is how to do it
—  but get a competent person to help you – electricity can be dangerous:
1. Buy a $20 multimeter
2. Unplug a solar panel and check for 10.5-15 volts.
2. Buy a hundred dollar 300W Power Inverter, a 700VA Uninterruptible Power Supply $150 (come swith its own battery), 12VDC inline Fuse Holder, 35 Amp fuse and 12V cable to reach from roof.
3. Run Cable from panel to fuse to indoors. Connect multimeter inline in Amps mode and connect to the inverter. Plug Inverter into UPS. Plug appliances into the UPS.
Sunlight will run up to 300 Watts via the inverter (check meter: amps x 12 volts = Watts). UPS battery will run your ADSL modem and a phone charger for few hours.

Grid tie solar useless in Queensland
With Queensland’s capital city Brisbane devastated in the Australian floods, householders are learning the disadvantages of grid tied solar.  Because of the way Utility companies the world over inisist on rigging it, grid-tied solar panels only produce power when the grid is running.
So they fail to fulfil the main purpose that many people have bought them for – to give safety and independence from the collapsing energy and financial system.
however, there are ways to convenrt the systems to work off the grid in emergencies – just a shame that the Utility companies do not provide a simple trip switch to allow the panels to operate off-grid when neccessary
Here is how to do it but get a competent person to help you – electricity can be dangerous:

1. Buy a $20 multimeter
2. Unplug a solar panel and check for 10.5-15 volts.
2. Buy a hundred dollar 300W Power Inverter, a 700VA Uninterruptible Power Supply $150 (come swith its own battery), 12VDC inline Fuse Holder, 35 Amp fuse and 12V cable to reach from roof.
3. Run Cable from panel to fuse to indoors. Connect multimeter inline in Amps mode and connect to the inverter. Plug Inverter into UPS. Plug appliances into the UPS.
Sunlight will run up to 300 Watts via the inverter (check meter: amps x 12 volts = Watts). UPS battery will run your ADSL modem and a phone charger for few hours.

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5 Responses to “Grid tie solar useless in Queensland flood crisis”

  1. uhx

    @nige the guy makes it look simple because it is simple and it’s also not dangerous at all.

    “But in principle I DISAGREE with your advice. Firstly, 99.9% of the panels in Grid Connected systems are 24V nominal”
    -But made out of 12 volt panels connected in a series, just unplug one from the other, solved.

    “these systems are generating 200-500VDC”
    -No they’re not, you’ve just said most are generating like 40vdc tops.

    “and can KILL”
    -Highly unlikely with 40vdc, not even with 40vac.

    “or start FIRES”
    -You put it out, solved (but also very unlikely to happen).

    “and especially on wet roofs..”
    -That’s sound advice, not mixing wet stuff with electricity, most people already know that though, so, not very dangerous.

    Deaths from it in Australia? How many deaths? I mean, every death is tragic and all, but one freak accident, or even 10 deaths because of that in all history in a country with 23.000.000 people is nothing to worry about, if you worry about odds like that then you can’t even walk in the street, in Australia 50 pedestrian children are killed by cars every year.

    Reply
  2. Dave

    Yes, grid tie isn’t made for ‘no power’ emergencies. If you wanted that you should have bought one with that capability, like the Sunny Island. It’s as if you bought car and then complained it wouldn’t pull your plough. You can get the options you want if you want to spend the money. Ignorance isn’t somebody else’s greed. Stay safe, and realize you will get through this.

    Reply
  3. Casey T

    Utility company politics are as vile as they come. Boasting their leadership and support for renewable energy while fighting clean energy policies and sponsoring regressive measures in the back room. As with most large private or corporate business, money calls the shots and monopoly is on the hidden agenda. As we depend more and more on utilities our rates will continue to increase and their insatiable hunger to monopolize will become more of a reality. As far as taking a grid tie system off grid, a UPS is a cheap and dirty way to get some bare bones power and for critical loads such as lights, phone, computer and/or a radio it would work great for a limited amount of time. You would however need a 12V panel to charge the battery (actual voltage should be from 15-18V) and most grid-tie panels have much higher voltage. There are ways to deal with this but I’m going to move on for now.
    A more serious system will be more money and, as Nick stated, a qualified person should be involved for obvious safety reasons. A bigger battery bank and a proper charge controller should be used while panels can be seperated from the array for the charge. While the grid is up, AC power can be used to keep the batteries topped off and ready to go. When power fails, the DC disconect switch should be off and panels can usually be unplugged at the connector clips that string them together and wired to the charge controller which maintains the charge on the batteries. It is definitely possible to set up a DIY off-grid system but if you aren’t sure of yourself, don’t try. You can call me at work during the week and I can help you get set up.
    Thing is, the reason most people don’t have a battery backup is because of the extra cost, a grid-tie system is expensive enough and grid power doesn’t go down all that often. But if you do want battery backup, the most proper way is with a bimodal inverter that will automatically switch when it senses a downed grid. This can be set up from the beginning and I have heard many a happy story during outages from people with power whose neighbors are without.

    Reply
  4. Big Bob

    Awesome web site!!!
    Harbor Freight sells inverters and solar panels. I used my inverter off my car during our last power outage. What the grid went down?? Free energy is an American right!!

    Reply
  5. nige

    Nick
    You raise an inteersting point, and an interesting solution.
    In principle I AGREE that its a travesty to see all that PV not being utilised.
    But in principle I DISAGREE with your advice. Firstly, 99.9% of the panels in Grid Connected systems are 24V nominal (>40V OC).

    Secondly your article makes is sound so simple that many people, especially ones suffering hardship could be tempted to do this themselves which is highly dangerous; these systems are generating 200-500VDC and can KILL or start FIRES, even if not connected to an inverter, and especially on wet roofs..

    This leads to my third concern and this is using ultra cheap UPS and Inverters to create AC and cheap fuses. We have already had deaths in Australia fom the use of poorly isolated inverters and shoddy prootection systems. The prospect of poor quality products producing AC in sodden conditions, and other panels being left in semi disconnected states producing hi voltage DC is a nightmare scenario.

    I woudl humbly suggest that buying one of the myriad of small protable solar re-chargers (Power Monkey etc) to recharge mobile phones would be cheaper, safer and faster.

    LEAVE THE HI VOLTAGE PV ON YOUR ROOFS ALONE, PEOPLE.

    Reply

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