Power Your Home With Solar In A Blackout – Without Batteries

Delta E5 hybrid inverter

You can partially power your home with a grid-connected solar panel system during a blackout without a battery. Here’s how it can be done.

One of the important safety features of a grid-connected PV system is when the grid is down, the system’s solar inverter will shut down too. If systems continued to export electricity to the mains grid during a blackout, this poses a major risk to workers attempting to fix the grid and could damage grid hardware. This safety feature is called anti-islanding.

To have access to electricity generated by your solar panels during a blackout, usually what’s required is an energy storage system. However, this isn’t always the case – for example, if you have a Delta E5 inverter.

Who Is Delta?

Founded in the 1970’s, Delta is a Taiwanese electronics manufacturing company. It’s probably best known in terms of solar manufacturing for its inverter products, but it has also moved into battery storage. SolarQuotes’ founder Finn is a fan of Delta, mainly due to his experiences with Delta hardware when he worked as a control systems engineer in a nuclear power plant in the UK many years ago.

“We used Delta power supplies from Delta Electronics,” says Finn. “I’ve always been very confident Delta as a company can make reliable electronics. What they’re not very good at is consumer-level marketing.”

Let’s call Delta a quiet achiever – and one of those achievements is built into its E5 inverter (5kW)1, which is listed on SQ’s hybrid inverter comparison table.

Delta E5 “Stand Alone” Mode

When the Delta E5 hybrid inverter loses grid connection, it goes into “Stand Alone” mode. The ATS (Automatic Transfer Switch) inside the inverter cuts any energy exports to the grid and only supplies the critical load circuit. Once a load is applied, the CT (Current Transformer) inside the inverter recognises the load requirements, converts the DC from the solar panels to AC and supplies exactly what is needed to the appliance/s. The E5 has a built-in CT clamp measuring the loads as they rise and fall.

Here’s a video showing the E5 it in action. It’s impressive stuff.

The feature won’t be much use to you at night or during extended periods of heavy cloud, but for those wanting to avoid plonking down a big wad of cash on a solar battery system and still have some blackout capabilities, the Delta E5 could be a good option. For example, a fridge/freezer could be run through the day to get through the night and the same goes for recharging battery powered lights, laptops and handheld devices. You’d just need to be careful in what loads were applied and keep an eye on the weather.

Being a hybrid inverter, the Delta E5 is ready for a battery should you choose to add one in the future. The cost of the E5 is around the $3,000 mark.

Also on the horizon is the Enphase IQ8 microinverter that will have stand-alone functionality. Enphase isn’t as modest as Delta, so we should be hearing plenty more about that soon.

Footnotes

  1. A 6.6kW solar power system is a good match for a 5kW inverter – learn more about oversizing
About Michael Bloch

Michael caught the solar power bug after purchasing components to cobble together a small off-grid PV system in 2008. He's been reporting on Australian and international solar energy news ever since.

Comments

  1. A less expensive option is a small gen set for the essentials and a properly set up change over switch. Managed this way through the aftermath of both a cyclone and the Brisbane storm a couple of years back, works through the night.

  2. Yeah, notwithstanding the power tends not to go out unless there has been some lightning, which usually comes with clouds…

  3. Gilbert Griffith says

    It’s a pity the E5 wasn’t available when we bought our 5kw system 5 years ago for AU$10000.
    I thought about installing a contactor to isolate from the mains, and powering up the solar inverter with a small generator, or even a UPS. But I doubt the inverter would regulate the output automatically.
    We also have far fewer power outages over the past few years.

  4. Robert bosshard says

    what can be done if one has microinverters on each panel?

    • If they are the – soon to be released – Enphase IQ 8 ‘Ensemble’ microinverters, then you can grid form just like the Delta. If they are older microinverters, you lose power with the grid.

  5. Robert Cannon says

    This is a good example of what is wrong with the state of solar technologies today, so many bits an pieces that might work to achieve limited ends. It reminds me of the state of audio visual technologies in the 1970s and 80s,. This domain is still not settled as anyone who has been to a few presentations in the recent past involving microphones and laptops.

  6. Robyn Parker says

    I’ve just had a quote from a local company and the guy has told me that the Enphase IQ7 will have this capability next year with a software update. Is this true or would i be looking at replacing IQ7’s with IQ8″s?

    • Only if you have an equal number of IQ8s installed also per Enphase‘s info so far. Otherwise the IQ7s will still lose power. So you would only have to replace half your IQ7s with IQ8s and install their isolating relay to isolate your house from the grid (~$2000 USD + whatever the IQ8s cost).

  7. I think that anti-islanding protection shouldn’t be installed in hybrid inverters. It should be part of energy meter which is supplied by grid energy provider (the same company which should be interested in protecting their employes with anti-islanding “feature”). During the grid power outage the energy meter should simply disconnect local installation from the grid and the hybrid inverter should keep working. Thanks to current idiotic implementation of anti-islanding I don’t see any reason to buy hybrid inverter.

  8. So, is there any significant functional difference between this Delta E5 inverter, and the Goodwe GW5048D-ES inverter?

  9. I have been advised that the Goodwe GW5048D-ES can be installed and operated without a battery system being connected (which then would allow for monitoring load, generation, and exporting, simultaneously, if my understanding is correct).

    Thus, it is my understanding, that both inverters have the ability to operate, with either batteries connected, or, no batteries connected.

    Thus, my understanding is that both inverters can be run with either batteries connected, or, no batteries connected, and, as the Goodwe GW5048D-ES apparently allows the PV panels to keep generating electricity, and, converting the electricity from the panels, for use by the household and battery charging, when grid supply failures occur, when batteries are connected, I expect that it can also do this, when no batteries are connected, unless I am otherwise informed.

    • Ronald Brakels says

      Sorry, I gave you the wrong Delta inverter link. Here’s the right one:

      https://www.deltapvi.com.au/assets/bulkUpload/E5-Brochure.pdf

      I’m afraid all I know about it is what I’ve read in that brochure. There are a limited number of inverters that say they can provide power to the home during a blackout without a battery by using power from the solar system. While this sounds good, in practice it’s difficult to manage as a cloud can easily drop output and cause the system to trip and even with clear skies solar generation will be low early and late in the day. On the bright side, it doesn’t take a lot of power to run a fridge and freezer and charge laptops. All else equal I’d rather have that function than not have it.

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